Drive guidance system and drive guidance method

Abstract

To provide a drive guidance system which enables the use of a regenerative brake at timing suitable for a driver.SOLUTION: A drive guidance system 1 comprises: an acquisition part 3 which acquires gradient information that a vehicle capable of executing the braking using a regenerative brake indicates the gradient of a road during travel; a determination part 5 which determines whether the use of the regenerative bake is effective when the vehicle travels on a traveling road of a predetermined forward section on the basis of the gradient information acquired by the acquisition part 3; and a notification part 7 which calls the attention of a driver of the vehicle to use the regenerative brake when the determination part 5 determines that the use of the regenerative brake is effective.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a driving guidance system and a driving guidance method.

Background Art

[0002] Conventionally, for a vehicle driver, driving conditions such as a speed limit considered to be optimal for the driver are notified based on information such as the shape of the road on which the vehicle is traveling, the position and speed of vehicles traveling around, and road signs, and a device for performing driving guidance is known (for example, Patent Document 1). According to this device, even when driving conditions such as the speed limit temporarily change due to factors such as rainfall, fog, accidents, and traffic jams, it is said that the vehicle can be safely driven by making a notification that reflects the change.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Some vehicles can use both a friction brake that utilizes frictional force and a regenerative brake that utilizes rotational resistance during power generation as brakes. When braking a vehicle that can use both a friction brake and a regenerative brake in this way, it is necessary for the driver to select and operate a brake that is considered appropriate according to the vehicle traveling and surrounding conditions.

[0005] However, when the driver selects the brake only based on their own judgment, whether the regenerative brake is used at an appropriate timing for the vehicle depends on the driver's knowledge of the regenerative brake and the driver's ability to grasp the running vehicle and the surrounding situation. Therefore, there was a possibility that the regenerative brake was not used efficiently by some drivers. In particular, the regenerative brake of a vehicle powered by electricity such as an electric vehicle or a hybrid vehicle can improve the electricity cost by recovering the electrical energy obtained by rotating the generator during braking. Therefore, when the regenerative brake is not used efficiently, there is a problem that the electricity cost of the vehicle deteriorates, and as a result, the impact on the environment also deteriorates.

[0006] The present invention has been made to solve such problems, and an object thereof is to provide a driving guidance system and a driving guidance method capable of causing a driver to use the regenerative brake at an appropriate timing.

Means for Solving the Problems

[0007] The driving guidance system of the present invention includes an acquisition means for acquiring gradient information indicating the gradient of a road on which a vehicle capable of braking by a regenerative brake is running, and based on the gradient information acquired by the acquisition means, when the vehicle runs on a traveling road of a predetermined section ahead, a determination means for determining whether the use of the regenerative brake is effective, and a notification means for notifying the driver of the vehicle to call for the use of the regenerative brake when the determination means determines that the use of the regenerative brake is effective.

[0008] The driving guidance method of the present invention includes an acquisition step of acquiring gradient information indicating the gradient of a road on which a vehicle capable of braking by a regenerative brake is running, a determination step of determining whether the use of the regenerative brake is effective when the vehicle runs on a traveling road of a predetermined section ahead based on the gradient information acquired in the acquisition step, and a notification step of notifying the driver of the vehicle to call for the use of the regenerative brake when it is determined in the determination step that the use of the regenerative brake is effective.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a driving guidance system and a driving guidance method that can cause a driver to use regenerative braking at an appropriate timing.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0011] Hereinafter, the present invention will be described along with preferred embodiments. Note that the present invention is not limited to the embodiments shown below, and can be appropriately changed without departing from the gist of the present invention. Also, in the embodiments shown below, there are some places where the illustration and description of some configurations are omitted. However, it goes without saying that well-known or widely known techniques are appropriately applied within the range where there is no contradiction with the content described below regarding the details of the omitted techniques.

[0012] First, the first embodiment will be described with reference to FIGS. 1 to 3. First, the outline of the driving guidance system 1 according to the first embodiment will be described with reference to FIG. 1. FIG. 1 is a configuration diagram showing the driving guidance system 1 according to the present embodiment. The driving guidance system 1 shown in FIG. 1 is mounted on a vehicle (so-called xEV) capable of braking by regenerative braking, such as an electric vehicle or a hybrid vehicle. The driving guidance system 1 shown in FIG. 1 includes an acquisition unit 3 (acquisition means), a determination unit 5 (determination means), and a notification unit 7 (notification means). The driving guidance system 1 also includes a vehicle speed acquisition unit 3b (vehicle speed acquisition means) and a front detection unit 3c (front detection means). The driving guidance system 1 has the acquisition unit 3 acquire gradient information indicating the gradient of the road on which the vehicle is traveling. When the determination unit 5 determines that the use of regenerative braking is effective when the vehicle travels on the forward road based on the acquired gradient information, the notification unit 7 prompts the driver to use regenerative braking.

[0013] In this way, when the vehicle approaches a slope where the use of regenerative braking is effective, the driving guidance system 1 notifies the driver to prompt the use of regenerative braking. That is, it estimates the road conditions ahead of the road on which the vehicle (own vehicle) is traveling and gives a prior notice to prompt the use of regenerative braking. Therefore, the driver can know the point where the use of regenerative braking is effective without searching for it himself / herself. Thus, the driver can be made to use regenerative braking at an appropriate timing, it becomes possible to improve the driver's energy-saving driving awareness, and it becomes possible to improve the electricity cost and reduce the environmental load.

[0014] Next, with reference to FIGS. 1 and 2, the details of the configurations of the acquisition unit 3, the vehicle speed acquisition unit 3b, the front detection unit 3c, the determination unit 5, and the notification unit 7 will be described. The acquisition unit 3 is a means for acquiring gradient information indicating the gradient of a road. The reason for acquiring the gradient information is that the effectiveness of using the regenerative brake varies depending on the gradient. Specific means for acquiring the gradient information can be exemplified as follows. First, there is a means for acquiring gradient information from the value of the acceleration sensor 9 possessed by the vehicle and the vehicle speed information indicating the vehicle speed. When acquiring gradient information from the value of the acceleration sensor 9 and the vehicle speed information indicating the vehicle speed, as shown in FIG. 1, the value of the acceleration detected by the acceleration sensor 9 and the vehicle speed information acquired by the vehicle speed acquisition unit 3b described later are input to the acquisition unit 3. The acquisition unit 3 acquires a specific gradient value as the gradient information from the input value of the acceleration and the vehicle speed indicated by the vehicle speed information. The gradient here can be exemplified by multiplying tanθ by 100 and expressing it in % notation when the gradient angle is θ, similar to the notation of the gradient of a general road sign, but the gradient angle itself may also be used. In the following description, unless otherwise specified, tanθ expressed in % notation is used as the gradient, with the uphill gradient indicated by a positive value and the downhill gradient indicated by a negative value respectively.

[0015] Here, the gradient refers to, for example, the average value of the gradient within the section in which the vehicle in motion is included among a plurality of sections obtained by dividing a road at regular intervals in the traveling direction. Further, it is preferable to define the gradient discretely for each predetermined gradient value, because it becomes easier to grasp the slope state compared to the case of reading the slope state only from the numerical value of the gradient. Specifically, for example, if the gradient is discretely classified into five levels, a slope state including a flat road (gradient 0%) and where the positive and negative gradients are within a predetermined range may be defined as "flat". Also, if the positive and negative gradients exceed "flat" and are less than a predetermined gradient, they may be defined as "gentle uphill" and "gentle downhill". Further, if the positive and negative gradients exceed the predetermined gradient, they may be defined as "steep uphill" and "steep downhill". In the following description, the gradient that is the boundary between "steep downhill" and "gentle downhill" may be referred to as the "first gradient". Also, the gradient that is the boundary between "gentle downhill" and "flat" may be referred to as the "second gradient". In this case, the first gradient and the second gradient are predetermined. Also, the second gradient is a downhill gradient with a larger gradient than the first gradient.

[0016] When obtaining gradient information from the value of the acceleration sensor 9 and the vehicle speed information, when the tire steps on road irregularities such as fallen trees or damaged parts of the road surface, the gradient indicated by the gradient information obtained from the value of the acceleration sensor 9 and the vehicle speed information may be steeper than the actual gradient. Therefore, the acquisition unit 3 may perform weighting on the gradient indicated by the gradient information and perform correction for smoothing to finally determine the gradient. For example, consider the case where a vehicle travels in order through sections "1" to "10" on a road with a gradient as shown in Fig. 2(a). In Fig. 2(a), the thin solid line means "flat", the broken line means "gentle downhill" or "gentle uphill", and the thick line means "steep downhill" or "steep uphill". Also, Fig. 2(b) shows the sections determined to be "steep uphill" or "steep downhill". Further, Fig. 2(c) shows an example in which the gradient is discretized into five levels, and the gradient surrounded by the thick frame is the finally determined gradient, and the gradient surrounded by the broken line is the gradient before correction. Also, the gradient shown by the dotted pattern in Fig. 2(c) indicates a gradient where the difference in gradient from the previous section is two levels or more.

[0017] As shown in Fig. 2(a), it is rare for the actual gradient to change in such a way that the gradient increases in four steps in one section, from "steep descent" to "steep ascent". For example, in the section from "3" to "5" in Fig. 2(a), the gradient changes step by step as "steep ascent" → "gentle ascent" → "flat". Therefore, for the obtained gradient, weighting may be performed considering the number of steps of change from the gradient in the previous section to correct the gradient. However, since the weighting is performed on the numerical value of the gradient and does not directly correct the discretized state of the slope, there are cases where the discretized state of the slope after weighting and correction remains unchanged from the discretized state of the slope before correction, and cases where it changes. For example, when the gradient indicated by the gradient information obtained from the value of the acceleration sensor 9 and the vehicle speed information in section "2" is "gentle ascent", the previous section "1" is "flat", and the difference in gradient between section "1" and section "2" is one step, so there is a high possibility of a natural change in the gradient. As an example of such a case, in Fig. 2(c), even if weighting is performed on the gradient obtained from the value of the acceleration sensor 9 and the vehicle speed information and corrected, when the corrected gradient is discretized, it remains the same "gentle ascent" as the discretized slope state before correction. On the other hand, when the gradient indicated by the gradient information obtained from the value of the acceleration sensor 9 and the vehicle speed information in section "6" is "steep descent", since the previous section "5" is "flat", the difference in gradient between section "5" and section "6" is two steps, and it may be affected by noise such as unevenness on the road. As an example of such a case, in Fig. 2(c), the result of discretizing the gradient after weighting and correcting the gradient indicated by the gradient information obtained from the value of the acceleration sensor 9 and the vehicle speed information shows an example where the gradient in section "6" changes to "gentle descent". As a specific weighting, a filter may be used that adds the weighted past gradient to a value obtained by multiplying the gradient indicated by the obtained gradient information by a numerical value in the range greater than 0 and less than 1 based on known filter theory. In section "10" as well, the gradient indicated by the gradient information obtained from the value of the acceleration sensor 9 and the vehicle speed information was "steep ascent", but since the previous section "9" was "steep descent", the difference in gradient between section "9" and section "10" is four steps, and it may be affected by noise.As an example of such a case, Fig. 2(c) shows the result of discretizing the gradient after weighting and correcting the gradient indicated by the value of the acceleration sensor 9 and the gradient information obtained from the vehicle speed information. In the interval "10", the gradient has changed to "downhill gently". By performing correction to smooth the gradient with weighting considering the gradient of the previous interval in this way, the influence of noise such as road unevenness can be eliminated. Although the possibility of a gradient change such as from "steep downhill" to "steep uphill" is rare but not zero, depending on the gradient value indicated by the acquired gradient information, the gradient after weighting may become a gradient such that it changes from "steep downhill" to "steep uphill". Therefore, the "weighting" here means applying a filter to the gradient value indicated by the acquired gradient information, and does not mean "correcting the gradient so that the gradient change is within one step when a gradient change of two or more steps occurs compared to the previous interval".

[0018] Next, as a means for acquiring gradient information, there is a means for acquiring gradient information from three-dimensional map information including the shape and gradient of the road on which the vehicle is traveling and the information on the current location of the vehicle. In this case, as shown in Fig. 1, 3D map information MI, which is three-dimensional map information including the shape and gradient of the road on which the vehicle is traveling, and a GPS signal GS, which is information on the current location of the vehicle, are input to the acquisition unit 3. The acquisition unit 3 acquires gradient information from the 3D map information MI and the GPS signal GS. More specifically, the acquisition unit 3 acquires the 3D map information MI and the GPS signal GS, fits the current location indicated by the GPS signal GS to the 3D map information MI, and acquires the gradient on the 3D map information MI at the current location of the vehicle as the gradient information. The 3D map information MI may be stored in advance in a storage unit (not shown) of the driving assistance system 1 or other in-vehicle devices, or may be acquired from an external server or the like that can communicate wirelessly with the acquisition unit 3. Here, GPS is an abbreviation for Global Positioning System. When the information on the current location of the vehicle is the GPS signal GS, the acquisition unit 3 has a function of receiving the GPS signal GS from GPS satellites.

[0019] In this way, the acquisition unit 3 acquires gradient information from the value of the acceleration sensor 9 and vehicle speed information, or acquires gradient information from the 3D map information MI and the GPS signal GS. When acquiring gradient information from the value of the acceleration sensor 9 and vehicle speed information, it is advantageous in that the existing acceleration sensor 9 in the vehicle and a vehicle speed sensor (not shown) can be diverted. Also, when acquiring gradient information from the value of the acceleration sensor 9 and vehicle speed information, since the gradient information of the road at the actual time of driving can be acquired, gradient information corresponding to changes in the gradient due to seasons, road works, etc. can be acquired. Further, when acquiring gradient information from the value of the acceleration sensor 9 and vehicle speed information, it is also advantageous in that it is not necessary to create a map in advance compared to the case of acquiring gradient information from the 3D map information MI and the GPS signal GS. On the other hand, when acquiring gradient information from the 3D map information MI and the GPS signal GS, unlike the case of acquiring gradient information from the value of the acceleration sensor 9 and vehicle speed information, it is advantageous in that gradient information can be acquired without being affected by noise such as road surface unevenness.

[0020] The vehicle speed acquisition unit 3b is a means for acquiring vehicle speed information indicating the vehicle speed of the vehicle in motion, here the own vehicle. The reason for acquiring the vehicle speed information is that when the vehicle speed is different, the effectiveness of using the regenerative brake may also be different. The vehicle speed acquisition unit 3b acquires, for example, a vehicle speed signal VI such as a vehicle speed pulse from a vehicle speed sensor of the vehicle as the vehicle speed information, and obtains the vehicle speed from the vehicle speed signal VI.

[0021] The front detection unit 3c is a means for acquiring other vehicle information which is information on other vehicles running in front of the vehicle. Specific examples of the other vehicle information include, for example, information indicating the inter-vehicle distance between the other vehicle and the own vehicle and the vehicle speed of the other vehicle. The front detection unit 3c shown in FIG. 1 acquires the video imaged by the camera 11 as the other vehicle information. The camera 11 is an in-vehicle device that images the front of the vehicle. When another vehicle is running in front of the vehicle, the other vehicle is reflected in the imaged video. The front detection unit 3c extracts the other vehicle from the video imaged by the camera 11 using a known image processing technique such as edge extraction, and obtains the inter-vehicle distance from the size, etc. of the extracted other vehicle in the video. Also, by acquiring the video at regular intervals and obtaining the time change of the position and size of the other vehicle in the video, the vehicle speed of the other vehicle, here the relative speed with respect to the own vehicle, is obtained.

[0022] The determination unit 5 is a means for determining whether the use of the regenerative brake is effective when the vehicle travels on a road in a predetermined section ahead based on the gradient information acquired by the acquisition unit 3, and the gradient information or the gradient indicated by the gradient information is input from the acquisition unit 3. The predetermined section ahead is a section in which driving is expected after the currently traveling section among a plurality of sections obtained by dividing the road at regular lengths. Specifically, it is ahead in the traveling direction, but when the vehicle is steering due to a right or left turn, etc., it may be ahead within the turning trajectory predicted by the steering. The vehicle speed information acquired by the vehicle speed acquisition unit 3b or the vehicle speed of the host vehicle indicated by the vehicle speed information is input to the determination unit 5 as necessary. The other vehicle information acquired by the forward detection unit 3c is also input to the determination unit 5 as necessary.

[0023] Specifically, the cases where it is determined that the use of the regenerative brake is effective can be exemplified as follows. First, when the acquisition unit 3 acquires gradient information, the determination unit 5 determines that the use of the regenerative brake is effective when the gradient indicated by the acquired gradient information is "steep descent" equal to or less than a first gradient which is a predetermined downward gradient. Since the vehicle can move forward by its own weight even on a downhill slope, the use of the regenerative brake is effective. In particular, in a section where the downhill slope continues for a long time, the regenerative brake can be used for a long period. On the other hand, as shown in FIG. 2, since the change in gradient often changes step by step, in the case of "steep descent", even when the gradient of the road in the section ahead of the currently traveling section changes to "flat" or "uphill", it often passes through a "gentle descent" section. Therefore, in the case of "steep descent", it can be predicted that at least the next section will continue to be a downhill slope. Thus, when the gradient indicated by the acquired gradient information is "steep descent", not only the presence or absence of a slope but also the estimation of the length of the slope, that is, "the downhill slope continues", can be made. Therefore, even without actually obtaining the length of the downhill, a section with a long downhill slope can be predicted, and the improvement of the electricity cost and the reduction of the environmental load by using the regenerative brake can be achieved.

[0024] Next, the determination unit 5 determines that the use of the regenerative brake is effective when the gradient indicated by the acquired gradient information is greater than the first gradient and less than or equal to the second gradient, i.e., "gentle downhill", and the vehicle speed indicated by the vehicle speed information acquired by the vehicle speed acquisition unit 3b is equal to or higher than a predetermined first vehicle speed. When the section where the vehicle is traveling is "gentle downhill", the gradient of the road in the next section may transition to "flat" or "uphill". Therefore, compared with the case of "steep downhill", the downhill slope may not continue for a long time. Thus, even if the actual length of the downhill slope is not determined, the length of the downhill slope can be predicted to some extent when the gradient indicated by the acquired gradient information is "gentle downhill". On the other hand, the higher the vehicle speed, the greater the rotational speed of the input shaft of the generator for the regenerative brake. Therefore, the amount of energy that can be recovered by using the regenerative brake increases. Therefore, when the vehicle speed is equal to or higher than the first vehicle speed, a corresponding amount of energy can be expected to be recovered by using the regenerative brake. In this way, when the gradient of the slope is "gentle downhill", by determining whether the use of the regenerative brake is effective in consideration of the vehicle speed, improvement in electricity costs and reduction of environmental load due to the use of the regenerative brake can be achieved. The first vehicle speed is specifically a vehicle speed at which energy recovery can be expected even in the case of gentle downhill, and it may be appropriately set according to the range of the gradient defined as "gentle downhill" and the like.

[0025] Furthermore, the determination unit 5 also determines that the use of the regenerative brake is effective when the following conditions (1) to (3) are satisfied. (1) The gradient indicated by the gradient information acquired by the acquisition unit 3 is "gentle downhill". (2) The vehicle speed of the vehicle indicated by the vehicle speed information acquired by the vehicle speed acquisition unit 3b is less than a predetermined first vehicle speed. (3) The other vehicle information acquired by the front detection unit 3c indicates that there is a vehicle traveling less than a predetermined inter-vehicle distance in front of the vehicle.

[0026] The case where the conditions (1) to (3) are satisfied specifically refers to the case where the road ahead is congested on a "downhill" slope. When the road ahead is congested, since the other vehicles ahead repeatedly start and stop, the vehicle (the own vehicle) also needs to repeatedly start and stop and frequently use the brakes. When the friction brake is frequently used in this case, the wear of the brake pads progresses. Especially in the case of a downhill slope, since the frictional force required for braking is larger than that on a flat road, the wear of the brake pads easily progresses. On the other hand, even if the regenerative brake is frequently used, wear of the components is less likely to occur. Therefore, when it is a downhill and the vehicle speed is less than a certain constant, and when the distance to the other vehicle running ahead is extremely close, the determination unit 5 determines that the use of the regenerative brake is effective, thereby suppressing the wear of the brake pads due to frequent use of the friction brake. The predetermined inter-vehicle distance is, for example, the average inter-vehicle distance when congestion occurs on a downhill slope. Also, the "other vehicle is running" as mentioned here includes the case where the other vehicle temporarily stops due to congestion.

[0027] In addition, the determination unit 5 also determines that the use of the regenerative brake is effective when the following conditions (4) to (6) are satisfied. (4) The slope indicated by the slope information acquired by the acquisition unit 3 is greater than the first slope and is a "downhill" slope equal to or less than the second slope. (5) The vehicle speed of the vehicle indicated by the vehicle speed information acquired by the vehicle speed acquisition unit 3b is less than a predetermined first vehicle speed. (6) The other vehicle information acquired by the forward detection unit 3c indicates that another vehicle is running ahead of the vehicle and the vehicle speed of the vehicle is faster than the vehicle speed of the other vehicle.

[0028] When the conditions (4) to (6) are satisfied, it is a "downhill" slope and the vehicle is approaching a congested section. In this case, in order to maintain the inter-vehicle distance according to the acceleration and deceleration of the vehicle ahead, it is necessary to repeatedly accelerate and decelerate the vehicle, and the brake is frequently used during deceleration. Therefore, by determining that the use of the regenerative brake is effective, the wear of the brake pads due to excessive use of the friction brake can be suppressed. Whether the vehicle speed of the vehicle is higher than that of other vehicles is determined from the relative speed of other vehicles acquired by the front detection unit 3c with respect to the host vehicle. In addition, the determination unit 5 may make a determination by adding, in addition to the conditions (4) to (6), the condition that "the inter-vehicle distance is shorter than a predetermined value". Thereby, it is possible to more clearly determine whether the vehicle is approaching a congested section. The "inter-vehicle distance" referred to here is, for example, a distance equal to or greater than the inter-vehicle distance when determining whether the conditions (1) to (3) are satisfied.

[0029] Furthermore, the determination unit 5 also determines that the use of the regenerative brake is effective when the following conditions (7) to (9) are satisfied. (7) The gradient indicated by the gradient information acquired by the acquisition unit 3 is greater than a predetermined second gradient (for example, a gradient indicating a "flat" road or an uphill slope such as a "gentle uphill"). (8) It is determined that a predetermined section before the section where the gradient information is acquired is a "downhill" (a "gentle downhill" or a "steep downhill") with a second gradient or less. (9) The vehicle speed indicated by the vehicle speed information acquired by the vehicle speed acquisition unit 3b in the section where the gradient information is acquired is equal to or higher than a predetermined second vehicle speed.

[0030] In this way, even when the traveling road is a flat road or an uphill slope, if the previous traveling section is a downhill slope and the vehicle speed is equal to or higher than a certain level, the determination unit 5 determines that it is effective to use the regenerative brake. When the previous traveling section is a downhill slope and the vehicle speed is equal to or higher than a certain level, even if the next section is a flat road or an uphill slope, energy can be efficiently recovered by using the regenerative brake due to the inertia of the vehicle. Therefore, even on an uphill slope or a flat road, when the conditions (7) to (9) are satisfied, the determination unit 5 determines that it is effective to use the regenerative brake. In this way, a major feature of the first embodiment is that the determination unit 5 can determine the conditions under which it is effective to use the regenerative brake not only when the vehicle is traveling on a downhill slope but also when it is traveling on an uphill slope. Note that the second vehicle speed is a vehicle speed at which energy recovery can be expected by using the regenerative brake even when the gradient transitions from a downhill to a non-downhill state such as "flat" or "gentle uphill". Also, the "previous predetermined section" is a predetermined section one or more before the section where the latest gradient information was obtained.

[0031] Note that the acquisition unit 3 can also acquire gradient information (first gradient information) from the value of the acceleration sensor 9 and the vehicle speed information, and further acquire gradient information (second gradient information) from the 3D map information MI, which is three-dimensional map information, and the GPS signal GS, which is information on the current location of the vehicle. In this case, when it is determined from at least one of the first gradient information and the second gradient information that it is effective to use the regenerative brake, the determination unit 5 may determine that it is effective to use the regenerative brake in the vehicle. In this way, it may be determined whether it is effective to use the regenerative brake based on both the first gradient information and the second gradient information. In this case, the driving guidance system 1 has both the advantages of acquiring gradient information from the value of the acceleration sensor 9 and the vehicle speed information and the advantages of acquiring gradient information from the map information and the information on the current location of the vehicle. Therefore, the driving guidance system 1 can more appropriately determine whether it is effective to use the regenerative brake.

[0032] The notification unit 7 is a means for notifying the driver of the vehicle to activate the regenerative brake when the determination unit 5 determines that the use of the regenerative brake is effective, and the determination result of the determination unit 5 is input thereto. When the determination unit 5 determines that the use of the regenerative brake is effective, the notification unit 7 causes, for example, character information indicating the activation of the regenerative brake to be displayed on the display unit 15 installed in the driver's seat. Alternatively, when the determination unit 5 determines that the use of the regenerative brake is effective, the notification unit 7 audibly conveys to the driver, for example, using the speaker 13 installed in the driver's seat, that the use of the regenerative brake is to be activated. When the determination unit 5 determines that the use of the regenerative brake is not effective, the notification unit 7 does nothing in particular.

[0033] In an electric vehicle or a hybrid vehicle, when the vehicle's battery is fully charged, the recovered energy cannot be stored even if the regenerative brake is used. However, even in the case of a fully charged battery, when the determination unit 5 determines that the use of the regenerative brake is effective, it is preferable for the notification unit 7 to issue a notification. This is because the driving guidance system 1 aims to guide the driver to use the regenerative brake at an appropriate timing. However, the driving guidance system 1 does not necessarily force the driver to use the regenerative brake. Therefore, when the driving guidance system 1 issues a notification to activate the regenerative brake, it does not necessarily need to monitor whether the driver actually uses the regenerative brake.

[0034] The driver who has received a notification to activate the regenerative brake from the notification unit 7 may activate the regenerative brake, for example, by reducing the depression angle of the accelerator pedal without using the foot brake when applying the brake. Alternatively, an operation may be performed to change to a driving mode in which the regenerative brake is more effective by means of a shift operation or a button operation.

[0035] The driving guidance system 1 shown in FIG. 1 may be implemented by storing a program that realizes the functions of the acquisition unit 3, vehicle speed acquisition unit 3b, forward detection unit 3c, determination unit 5, and notification unit 7 in the storage unit of a general-purpose computer and executing each program with the central processing unit of the general-purpose computer. Alternatively, the driving guidance system 1 may be realized as a dedicated machine using an integrated circuit that realizes the functions of the acquisition unit 3, vehicle speed acquisition unit 3b, forward detection unit 3c, determination unit 5, and notification unit 7, such as a so-called embedded system. The above is the description of the configuration of the driving guidance system 1 according to the first embodiment.

[0036] Next, a driving guidance method using the driving guidance system 1 will be described with reference to FIG. 3. First, the outline of the driving guidance method will be described. First, the acquisition unit 3 acquires gradient information indicating the gradient of the road on which a vehicle capable of braking by regenerative braking is traveling (acquisition step). Next, the determination unit 5 determines whether it is effective to use the regenerative brake when the vehicle travels on the road in a predetermined section ahead based on the gradient information acquired in the acquisition step (determination step). If the determination unit 5 determines in the determination step that it is effective to use the regenerative brake, the notification unit 7 issues a notification to prompt the driver of the vehicle to use the regenerative brake (notification step).

[0037] Next, the details of the driving guidance method will be described. FIG. 3 is a flowchart showing a driving guidance method using the driving guidance system 1. First, the acquisition unit 3 acquires gradient information indicating the gradient of the road on which a vehicle capable of braking by regenerative braking is traveling (S1 in FIG. 3, acquisition step). Specifically, the acquisition unit 3 acquires the acceleration of the vehicle from the value of the acceleration sensor 9, and further acquires the vehicle speed information from the vehicle speed acquisition unit 3b. Further, the acquisition unit 3 obtains the gradient as gradient information from the acquired acceleration and vehicle speed information. Alternatively, the acquisition unit 3 acquires the 3D map information MI and the GPS signal GS, acquires the information on the current location of the vehicle from the GPS signal GS, applies the acquired information on the current location to the 3D map information MI, and obtains the gradient of the road at the current location of the vehicle as gradient information. When the gradient is discretely assigned and defined as shown in FIG. 2, it may be discretized in S1.

[0038] Next, the determination unit 5 determines whether the slope of the road indicated by the slope information acquired by the acquisition unit 3 in S1 is "steep downhill", specifically, whether it is equal to or less than the first slope. If it is determined to be "steep downhill", the process proceeds to S3. If it is determined not to be "steep downhill", the process proceeds to S4 (S2 in FIG. 3, determination step). If the slope is not discretized in S1, it may be discretized in S2. When the determination unit 5 determines to be "steep downhill" in S2, the determination unit 5 determines that the use of the regenerative brake is effective and causes the notification unit 7 to issue a notification to evoke the use of the regenerative brake using the display unit 15 and the speaker 13 (S3 in FIG. 3, notification step). When the determination unit 5 determines not to be "steep downhill" in S2, the determination unit 5 determines whether the slope of the road indicated by the slope information acquired by the acquisition unit 3 in S1 is "gentle downhill", specifically, whether it is greater than the first slope and equal to or less than the second slope. If the result is determined to be "gentle downhill", the process proceeds to S5. If it is determined not to be "gentle downhill", the process proceeds to S6 (S4 in FIG. 3, determination step). When it is determined to be "gentle downhill" in S4, the determination unit 5 causes the vehicle speed acquisition unit 3b to acquire vehicle speed information (S5 in FIG. 3), determines whether the vehicle speed indicated by the vehicle speed information is equal to or higher than the first vehicle speed. If it is equal to or higher than the first vehicle speed, the process proceeds to S3. If it is not equal to or higher than the first vehicle speed, the process proceeds to S8 (S7 in FIG. 3). When it is determined in S7 that the vehicle speed is equal to or higher than the first vehicle speed, the determination unit 5 determines that the use of the regenerative brake is effective and causes the notification unit 7 to issue a notification to evoke the use of the regenerative brake using the display unit 15 and the speaker 13 (S3 in FIG. 3, notification step).

[0039] When the determination unit 5 determines that the vehicle speed is not equal to or higher than the first vehicle speed in S7, the determination unit 5 causes the front detection unit 3c to acquire other vehicle information by imaging the front using the camera 11 or the like (S8 in FIG. 3). Next, the determination unit 5 determines from the other vehicle information whether at least one of the following two conditions is satisfied: whether there is another vehicle traveling ahead and the inter-vehicle distance is less than a predetermined inter-vehicle distance, or whether there is another vehicle traveling ahead and the vehicle speed of the vehicle (own vehicle) is faster than the vehicle speed of the other vehicle (S9 in FIG. 3). When the determination unit 5 determines that at least one of the two conditions is satisfied, the determination unit 5 determines that the use of the regenerative brake is effective, proceeds to S3, and causes the notification unit 7 to issue a notification to prompt the use of the regenerative brake (S3 in FIG. 3, notification step). When it is determined that neither of the two conditions is satisfied, the process proceeds to S10, and the process returns without causing the notification unit 7 to issue a notification to prompt the use of the regenerative brake (S10 in FIG. 3).

[0040] When the determination unit 5 determines in S4 that the gradient is not "downhill", the determination unit 5 refers to the gradient information acquired by the acquisition unit 3 in the past, etc., and determines whether the gradient in a predetermined section before the section where the gradient information was acquired in S1, for example, the previous section, was downhill ("gentle downhill" or "steep downhill"). If it is determined that it was downhill, the process proceeds to S11; if it is determined that it was not downhill, the process proceeds to S10 (S6 in FIG. 3, determination step). When the determination unit 5 determines in S6 that the gradient of the previous section was downhill, the determination unit 5 causes the vehicle speed acquisition unit 3b to acquire the vehicle speed information of the vehicle (own vehicle) (S11 in FIG. 3), and determines whether the vehicle speed indicated by the acquired vehicle speed information is equal to or higher than the second vehicle speed. If it is determined that the vehicle speed is equal to or higher than the second vehicle speed, the process proceeds to S3; if it is determined that the vehicle speed is not equal to or higher than the second vehicle speed, the process proceeds to S10 (S12 in FIG. 3). When it is determined in S12 that the vehicle speed is equal to or higher than the second vehicle speed, the determination unit 5 determines that the use of the regenerative brake is effective, and causes the notification unit 7 to issue a notification to prompt the use of the regenerative brake using the display unit 15 and the speaker 13 (S3 in FIG. 3, notification step). When the determination unit 5 determines in S6 that the gradient of the previous predetermined section was not downhill, and when the determination unit 5 determines in S12 that the vehicle speed is not equal to or higher than the second vehicle speed, the determination unit 5 returns without causing the notification unit 7 to issue a notification to prompt the use of the regenerative brake (S10 in FIG. 3). The above is the description of the flow shown in FIG. 3.

[0041] Thus, in the first embodiment, when the acquisition unit 3 acquires the gradient information of the road during travel and the determination unit 5 determines that it is effective to use the regenerative brake when traveling on the forward road based on the acquired gradient information, the notification unit 7 calls for the use of the regenerative brake.

[0042] Therefore, the driver can know the effective points for using the regenerative brake without searching for them by himself / herself. Thus, the driver can be made to use the regenerative brake at an appropriate timing, the driver's energy-saving driving awareness can be improved, and the improvement of electricity consumption and the reduction of environmental load can be achieved.

[0043] Also, in the first embodiment, the acquisition unit 3 acquires the gradient information from the value of the acceleration sensor 9 and the vehicle speed information of the vehicle, or acquires the gradient information from the 3D map information MI and the GPS signal GS. When acquiring the gradient information from the value of the acceleration sensor 9 and the vehicle speed information, the existing acceleration sensor 9 and vehicle speed sensor in the vehicle can be diverted. Also, when acquiring the gradient information from the value of the acceleration sensor 9 and the vehicle speed information, since the gradient of the road at the actual time of travel can be measured, gradient information corresponding to changes in the gradient due to seasons, road construction, etc. can be acquired. Further, when acquiring the gradient information from the value of the acceleration sensor 9 and the vehicle speed information, the map creation work is not required in advance compared to the case of acquiring the gradient information from the 3D map information MI and the GPS signal GS. On the other hand, when acquiring the gradient information from the 3D map information MI and the GPS signal GS, unlike the case of acquiring the gradient information from the value of the acceleration sensor 9 and the vehicle speed information, the gradient information can be acquired without being affected by noise such as road surface unevenness.

[0044] Furthermore, in the first embodiment, when the gradient indicated by the gradient information acquired by the acquisition unit 3 is "steep descent" where the gradient is less than or equal to a predetermined first gradient and the determination unit 5 determines that it is so, the determination unit 5 determines that the use of the regenerative brake is effective. In this configuration, when the driving guidance system 1 determines that the road is a "steep descent", it prompts the use of the regenerative brake. In the case of a "steep descent", since the gradient of the road often changes to "flat" or "uphill" or passes through a "gentle descent", it can be predicted that the downhill section will continue at least in the next section. Therefore, even without actually determining the length of the downhill section, a long downhill section can be predicted, and the electricity cost can be improved and the environmental load can be reduced by using the regenerative brake.

[0045] Also, in the first embodiment, the driving guidance system 1 includes a vehicle speed acquisition unit 3b. When the gradient indicated by the gradient information acquired by the acquisition unit 3 is a "gentle descent" and the vehicle speed indicated by the vehicle speed information acquired by the vehicle speed acquisition unit 3b is equal to or higher than a first vehicle speed, the determination unit 5 determines that the use of the regenerative brake is effective. In this configuration, when the road is a "gentle descent" and the vehicle speed is a certain value or higher, the driving guidance system 1 prompts the use of the regenerative brake. Thus, when the gradient of the slope is a "gentle descent", by determining whether the use of the regenerative brake is effective in consideration of the vehicle speed, the electricity cost can be improved and the environmental load can be reduced by using the regenerative brake.

[0046] On the other hand, in the first embodiment, when the gradient indicated by the gradient information acquired by the acquisition unit 3 is a "gentle descent", the vehicle speed of the vehicle is less than the first vehicle speed, and the front detection unit 3c detects that another vehicle is traveling in front of the vehicle at a distance less than a predetermined inter-vehicle distance, the determination unit 5 determines that the use of the regenerative brake is effective. In this configuration, when the road is a "gentle descent" and the vehicle speed is less than a certain value, and the distance to another vehicle traveling in front is close, the driving guidance system 1 prompts the use of the regenerative brake. In this case, when the vehicle is traveling on a slope during a traffic jam and needs to repeatedly start and stop the vehicle and frequently use the brake, by prompting the use of the regenerative brake, the wear of the brake pads due to excessive use of the friction brake can be suppressed.

[0047] Furthermore, in the first embodiment, the determination unit 5 determines that the use of the regenerative brake is effective when the gradient indicated by the gradient information is "downhill gradually", the vehicle speed is less than the first vehicle speed, there is another vehicle traveling ahead, and the front detection unit 3c detects information indicating that the vehicle speed is higher than that of the other vehicle. In this configuration, when the driving road is "downhill gradually" and the vehicle speed is less than a certain speed, and the vehicle speed (own vehicle) is higher than that of another vehicle traveling ahead, the driving guidance system 1 prompts the use of the regenerative brake. In this case, it is a situation where the vehicle is approaching a congested point while traveling on a slope, and it is necessary to repeat acceleration and deceleration and use the brake frequently. Therefore, by prompting the use of the regenerative brake, it is possible to suppress the wear of the brake pads due to frequent use of the friction brake.

[0048] Also, in the first embodiment, even when the gradient indicated by the gradient information acquired by the acquisition unit 3 is a gradient indicating a flat road or an uphill slope, if the previous driving section is a downhill slope and the vehicle speed is equal to or higher than the second vehicle speed, the determination unit 5 determines that the use of the regenerative brake is effective. In this way, when the previous driving section is a downhill slope and the vehicle speed is a certain level or higher, even if the next section is a flat road or an uphill slope, due to the inertia of the vehicle, energy can be efficiently recovered by using the regenerative brake. Therefore, the driver can be made aware of places where the use of the regenerative brake is effective even on an uphill slope.

[0049] Furthermore, the driving guidance method of the first embodiment includes an acquisition step of acquiring gradient information, a determination step of determining whether the use of the regenerative brake is effective when the vehicle travels forward, and a notification step of prompting the use of the regenerative brake when it is determined that the use of the regenerative brake is effective.

[0050] Therefore, the driver can be informed of places where the use of the regenerative brake is effective without having to search for them himself / herself. Thus, the driver can be made to use the regenerative brake at an appropriate timing, which can improve the driver's energy-saving driving awareness, and it becomes possible to improve the electricity cost and reduce the environmental load.

[0051] Next, a second embodiment will be described with reference to FIGS. 4 and 5. In the second embodiment, in the first embodiment, the gradient information is obtained from the map information in which a slope where the use of the regenerative brake is effective is registered in advance as a regenerative braking activation point. Note that, for elements that perform the same functions as those in the first embodiment in the second embodiment, the same numbers are assigned, and mainly the differences from the first embodiment will be described.

[0052] First, the outline of the driving guidance system 1a according to the second embodiment will be described with reference to FIG. 4. FIG. 4 is a configuration diagram showing the driving guidance system 1a according to the second embodiment. The driving guidance system 1a shown in FIG. 4 includes an acquisition unit 3 (acquisition means), a determination unit 5 (determination means), and a notification unit 7 (notification means) in the same manner as the first embodiment. However, the driving guidance system 1a uses information in which a slope where the use of the regenerative brake is effective is registered in advance as a regenerative braking activation point (registration information) as map information, here 3Dmap information MI. A slope where the use of the regenerative brake is effective is, for example, a slope with a continuous downhill for a predetermined length. The gradient and length serving as criteria for determining whether to set a slope as a regenerative braking activation point are set in advance according to the energy recovery efficiency when the regenerative brake is used. The entity that registers the regenerative braking activation point in the map information is not particularly limited. Slopes that meet the criteria as regenerative braking activation points may be automatically registered or manually registered. Note that, in FIG. 4, 3Dmap information MI is illustrated as the map information. However, when the regenerative braking activation point is registered, since the regenerative braking activation point includes gradient information, the registered map information may be two-dimensional information instead of three-dimensional information. Also, although the regenerative braking activation point itself is position information indicating a specific point, since that point is a slope with a continuous downhill, the regenerative braking activation point corresponds to information including a gradient. Therefore, the acquisition unit 3 can acquire information on whether the current location is a point registered as a regenerative braking activation point as gradient information from the map information in which the regenerative braking activation point is registered in advance and the information on the current location of the vehicle.

[0053] In this way, when the acquisition unit 3 acquires gradient information from the map information in which the regeneration activation point is registered in advance and the current location information of the vehicle, the determination unit 5 determines that the use of the regeneration brake is effective when it determines that the vehicle has passed through the regeneration activation point. In this way, when the determination unit 5 determines that the use of the regeneration brake is effective when passing through the regeneration activation point registered in the map information in advance, once the regeneration activation point is registered, thereafter, it is possible to instantaneously determine a place where the use of the regeneration brake is effective without obtaining the gradient and length of the slope. Note that in the second embodiment, since whether or not the vehicle has passed through the regeneration activation point is the criterion for whether or not the use of the regeneration brake is effective, the driving support system 1a does not necessarily need to include the vehicle speed acquisition unit 3b and the forward detection unit 3c.

[0054] Next, the details of the driving support method using the driving support system 1a according to the second embodiment will be described with reference to FIG. 5. FIG. 5 is a flowchart showing the procedure of the driving support method using the driving support system 1a. First, the acquisition unit 3 of the driving support system 1a acquires 3D map information MI as map information in which the regeneration activation point is registered (S21 in FIG. 5, acquisition step). Next, the acquisition unit 3 acquires a GPS signal GS as current location information from a GPS satellite (S22 in FIG. 5, acquisition step). Note that the order of S21 and S22 may be reversed, or they may be performed simultaneously.

[0055] Next, the acquisition unit 3 applies the GPS signal GS to the 3D map information MI to determine the current location of the vehicle (the host vehicle), and acquires information on whether the current location is the regeneration activation point as gradient information. Further, the determination unit 5 determines from the gradient information whether the current location is the point registered as the regeneration activation point, and if it is determined that it is the registered point, proceeds to S24, and if it is determined that it is not the registered point, proceeds to S25 (S23 in FIG. 5, determination step). When it is determined in S23 that the current location of the vehicle (the host vehicle) is the registered point, the determination unit 5 determines that the use of the regenerative brake is effective, and causes the notification unit 7 to issue a notification to activate the use of the regenerative brake using the display unit 15 and the speaker 13 (S24 in FIG. 5, notification step). When it is determined in S23 that the current location of the vehicle (the host vehicle) is not the registered point, the determination unit 5 returns without causing the notification unit 7 to issue a notification to activate the use of the regenerative brake (S25 in FIG. 5). The above is a detailed description of the driving guidance method using the driving guidance system 1a.

[0056] As described above, in the second embodiment, the acquisition unit 3 acquires gradient information indicating the gradient of the road during travel, and based on the gradient information, when the determination unit 5 determines that the use of the regenerative brake is effective when traveling on the forward road, the notification unit 7 activates the use of the regenerative brake. Therefore, the same effect as in the first embodiment is achieved.

[0057] On the other hand, in the second embodiment, the acquisition unit 3 acquires gradient information from the 3D map information MI in which a slope where the use of the regenerative brake is effective is registered in advance as the regeneration activation point and the GPS signal GS. Further, the determination unit 5 determines that the use of the regenerative brake is effective when the vehicle passes through the regeneration activation point. With this configuration, a notification to promote the use of the regenerative brake is issued when passing through the regeneration activation point registered in the map in advance. Therefore, once the regeneration activation point is registered, it is possible to instantaneously determine a place where the use of the regenerative brake is effective without obtaining the gradient and length of the slope thereafter.

[0058] Next, a third embodiment will be described with reference to FIGS. 6 and 7. The second embodiment is a combination of the first embodiment and the second embodiment. Note that elements in the third embodiment that perform the same functions as those in the first embodiment and the second embodiment are given the same numbers, and mainly the parts different from the first embodiment and the second embodiment will be described.

[0059] First, the outline of the driving guidance system 1b according to the third embodiment will be described with reference to FIG. 6. FIG. 6 is a configuration diagram showing the driving guidance system 1b according to the third embodiment. The driving guidance system 1b shown in FIG. 6 includes an acquisition unit 3, a vehicle speed acquisition unit 3b, a front detection unit 3c, a determination unit 5, and a notification unit 7, similar to the first embodiment. However, the driving guidance system 1b can acquire gradient information from the value of the acceleration sensor 9 and vehicle speed information as the first gradient information, and can also acquire gradient information from the 3D map information MI in which the regeneration activation point is registered and the GPS signal GS as the second gradient information. In this configuration, when it is determined that the use of the regenerative brake is effective from at least one of the first gradient information acquired by the acquisition unit 3 and the second gradient information, the determination unit 5 determines that the use of the regenerative brake in the host vehicle is effective. Therefore, it has both the advantages of acquiring gradient information from the value of the acceleration sensor 9 and vehicle speed information and the advantages of acquiring gradient information from map information and the information on the current location of the vehicle, and can perform more appropriate activation of the regenerative brake.

[0060] Next, the details of the driving guidance method using the driving guidance system 1b according to the third embodiment will be described. FIG. 7 is a flowchart showing the procedure of the driving guidance method using the driving guidance system 1b. First, the acquisition unit 3 of the driving guidance system 1 acquires the 3D map information MI as map information in which the regeneration activation point is registered (S31 in FIG. 7, acquisition step). Next, the acquisition unit 3 acquires the GPS signal GS as information on the current location from a GPS satellite or the like (S32 in FIG. 7, acquisition step). Note that the order of S31 and S32 may be reversed, or they may be performed simultaneously.

[0061] Next, the determination unit 5 applies the GPS signal GS to the 3D map information MI to obtain the current location of the vehicle (own vehicle), and acquires information on whether the current location is the regeneration activation point as gradient information. Further, the determination unit 5 determines whether the current location is a point registered as the regeneration activation point from the gradient information. If it is determined that the location is a registered point, the process proceeds to S34. If it is determined that the location is not a registered point, the process proceeds to S1 in FIG. 3 (S33 in FIG. 7, determination step). When it is determined in S33 that the current location of the vehicle (own vehicle) is a registered point, the determination unit 5 determines that the use of the regenerative brake is effective, and causes the notification unit 7 to issue a notification to activate the use of the regenerative brake using the display unit 15 and the speaker 13 (S34 in FIG. 7, notification step). When it is determined in S33 that the current location of the vehicle (own vehicle) is not a registered point, the determination unit 5 proceeds to S1 in FIG. 3, and thereafter acquires gradient information from the value of the acceleration sensor 9 and the vehicle speed information to determine whether the use of the regenerative brake is effective. The flow shown in FIG. 7 is such that the determination unit 5 determines whether the use of the regenerative brake is effective in the same procedure as in the second embodiment. When it is not determined that the use of the regenerative brake is effective, the determination is made in the same procedure as in the first embodiment to determine whether the use of the regenerative brake is effective. However, the order of determination may be reversed. Specifically, the determination unit 5 may determine whether the use of the regenerative brake is effective in the same procedure as in the first embodiment. When it is not determined that the use of the regenerative brake is effective, the determination may be made in the same procedure as in the second embodiment to determine whether the use of the regenerative brake is effective. The above is a detailed description of the driving guidance method using the driving guidance system 1b.

[0062] As described above, in the third embodiment, the acquisition unit 3 acquires gradient information indicating the gradient of the road during travel. Based on the gradient information, when the determination unit 5 determines that the use of the regenerative brake is effective when traveling on the forward road, the notification unit 7 activates the use of the regenerative brake. Therefore, the same effect as in the first embodiment is achieved.

[0063] Further, in the third embodiment, when it is determined from at least one of the first gradient information and the second gradient information that the use of the regenerative brake is effective, the determination unit 5 determines that the use of the regenerative brake in the host vehicle is effective. In this configuration, when it is determined from at least one of the first gradient information and the second gradient information that the use of the regenerative brake is effective, the driving guidance system 1b prompts the use of the regenerative brake. Therefore, the driving guidance system 1b has both the advantages of obtaining the first gradient information from the value of the acceleration sensor 9 and the vehicle speed information, and the advantages of obtaining the second gradient information from the 3D map information MI and the GPS signal GS. Thus, the driving guidance system 1b can perform more appropriate regenerative brake prompting.

[0064] As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiments, and modifications may be made without departing from the spirit of the present invention, and other technologies may be appropriately combined within the possible range. Furthermore, known or well-known technologies may be combined within the possible range.

Explanation of Reference Numerals

[0065] 1, 1a, 1b: Driving guidance system 3: Acquisition unit (acquisition means) 3b: Vehicle speed acquisition unit (vehicle speed acquisition means) 3c: Forward detection unit (forward detection means) 5: Determination unit (determination means) 7: Notification unit (notification means) 9: Acceleration sensor GS: GPS signal (information on the current location) MI: 3D map information (three-dimensional map information)

Claims

1. An acquisition means for acquiring gradient information indicating the gradient of a road on which a vehicle capable of braking by regenerative braking is traveling; A determination means for determining whether it is effective to use the regenerative brake when the vehicle travels on a traveling road in a predetermined section ahead based on the gradient information acquired by the acquisition means; A notification means for notifying the driver of the vehicle to use the regenerative brake when the determination means determines that it is effective to use the regenerative brake A driving guidance system characterized by comprising.

2. Comprising a vehicle speed acquisition means for acquiring vehicle speed information indicating the vehicle speed of the vehicle, The acquisition means, Acquires the gradient information from the value of the acceleration sensor of the vehicle and the vehicle speed information, or acquires the gradient information from three-dimensional map information and the current location information of the vehicle The driving guidance system according to claim 1, characterized in that.

3. The determination means, Determines that it is effective to use the regenerative brake when the gradient indicated by the gradient information acquired by the acquisition means is a steep downhill of a first gradient or less which is a predetermined downhill gradient The driving guidance system according to claim 2, characterized in that.

4. Comprising a vehicle speed acquisition means for acquiring vehicle speed information indicating the vehicle speed of the vehicle, The determination means, The gradient indicated by the gradient information acquired by the acquisition means is greater than the first gradient and is a gentle downhill of a second gradient or less which is a predetermined downhill gradient greater than the first gradient, and further the vehicle speed information acquired by the vehicle speed acquisition means indicates that the vehicle speed of the vehicle is a first predetermined vehicle speed or more. In this case, it is determined that it is effective to use the regenerative brake The driving guidance system according to claim 3, characterized in that.

5. Comprising a forward detection means for acquiring other vehicle information which is information of other vehicles traveling ahead of the vehicle, The determination means, The gradient indicated by the gradient information acquired by the acquisition means is greater than the first gradient and is a gentle downhill of a second gradient or less, and further the vehicle speed information acquired by the vehicle speed acquisition means indicates that the vehicle speed of the vehicle is less than the first vehicle speed. In this case, when the other vehicle information acquired by the forward detection means indicates that the other vehicle is traveling within a predetermined inter-vehicle distance in front of the vehicle, it is determined that it is effective to use the regenerative brake The driving guidance system according to claim 4, characterized in that.

6. It is provided with a front detection means for acquiring other vehicle information which is information of another vehicle traveling in front of the vehicle. The determination means When the gradient indicated by the gradient information acquired by the acquisition means is a downhill with a gradient greater than the first gradient and less than or equal to the second gradient, and further when the vehicle speed information acquired by the vehicle speed acquisition means indicates that the vehicle speed of the vehicle is less than the first vehicle speed, and the other vehicle information acquired by the front detection means indicates that the other vehicle is traveling in front of the vehicle and the vehicle speed of the vehicle is faster than the vehicle speed of the other vehicle, it is determined that the use of the regenerative brake is effective. The driving guidance system according to claim 4, characterized in that.

7. The determination means When the gradient indicated by the gradient information acquired by the acquisition means is a gradient indicating an uphill slope or a flat road greater than a second gradient which is a downhill gradient greater than the first gradient, and it is determined that a predetermined section before the section where the gradient information is acquired is a downhill with a gradient less than or equal to the second gradient, and further when the vehicle speed information acquired by the vehicle speed acquisition means in the section where the gradient information is acquired indicates that the vehicle speed of the vehicle is equal to or higher than a predetermined second vehicle speed, it is determined that the use of the regenerative brake is effective. The driving guidance system according to any one of claims 3 to 6, characterized in that.

8. The acquisition means Acquires the gradient information from the map information in which a slope where the use of the regenerative brake is effective is registered in advance as a regenerative activation point and the current location information of the vehicle. The determination means When it is determined that the vehicle has passed the regenerative activation point, it is determined that the use of the regenerative brake is effective. The driving guidance system according to claim 1, characterized in that.

9. It is provided with a vehicle speed acquisition means for acquiring vehicle speed information indicating the vehicle speed of the vehicle. The acquisition means acquires the gradient information as first gradient information from the value of the acceleration sensor of the vehicle and the vehicle speed information, and further acquires the gradient information as second gradient information from three-dimensional map information and the current location information of the vehicle. The determination means When it is determined that the use of the regenerative brake is effective from at least one of the first gradient information and the second gradient information acquired by the acquisition means, it is determined that the use of the regenerative brake in the vehicle is effective. The driving guidance system according to claim 1, characterized in that.

10. An acquisition step of acquiring gradient information indicating a gradient of a road on which a vehicle capable of braking by a regenerative brake is traveling; A determination step of determining whether it is effective to use the regenerative brake when the vehicle travels on a traveling road in a predetermined section ahead based on the gradient information acquired in the acquisition step; A notification step of, when it is determined in the determination step that it is effective to use the regenerative brake, notifying the driver of the vehicle to prompt the use of the regenerative brake A driving guidance method characterized by including the above.

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