Vehicle driving support device

Abstract

To select a followed vehicle most advantageous in fuel economy, and notify a driver of it.SOLUTION: A vehicle driving support device comprises: an other vehicle information acquisition section (Steps S1 to S4) which acquires information on travel states of other vehicles traveling around an own vehicle; an other vehicle acceleration and deceleration detection section (Steps S5 and S6) which obtains acceleration and deceleration of other vehicles repeatedly accelerating and coasting on the basis of the acquired information; an other vehicle evaluation section (Steps S5 and S6) which obtains degrees of similarity in acceleration between the obtained acceleration of other vehicles and fuel economy optimization acceleration of the own vehicle, obtains degrees of similarity in deceleration between the obtained deceleration of other vehicles and fuel economy optimization deceleration of the own vehicle, and weights the degrees of similarity in acceleration; and a followed vehicle recommendation section (Step S7) which selects another vehicle to be considered as a followed vehicle from other vehicles traveling around the own vehicle, on the basis of the weighted degrees of similarity in acceleration and the degrees of similarity in deceleration, and notifies a driver of the own vehicle of it.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a device that mechanically performs part of driving operations such as acceleration, deceleration, and steering while the vehicle is running, and supports the driving operation by the driver. In particular, it relates to a device that controls acceleration running and coasting so as to maintain a vehicle-to-vehicle distance and follow a preceding vehicle.

Background Art

[0002] An example of this type of device is described in Patent Document 1. The device is configured to control the driving force and braking force of the host vehicle so as to perform platoon running while maintaining the vehicle-to-vehicle distance. When running following a preceding vehicle, within the range of maintaining the vehicle-to-vehicle distance, it is configured to repeatedly perform so-called acceleration running that generates a driving force and so-called coasting that stops both the engine and the motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the device described in Patent Document 1, the engine or motor is driven to accelerate so that the inter-vehicle distance from the preceding vehicle falls between a predetermined maximum and minimum, and coasting in which both the engine and the motor are stopped is repeated. By doing so, the energy efficiency such as fuel consumption or electricity cost during following driving or platooning is improved. However, as long as the vehicle is following the preceding vehicle and maintaining the inter-vehicle distance within a predetermined range, the so-called driving manner such as vehicle speed and the timing of acceleration and deceleration is affected by the preceding vehicle. Also, the preceding vehicle is a vehicle existing in front of the host vehicle and detected by a radar or the like. Therefore, the detected preceding vehicle may be different from the host vehicle in terms of vehicle class or vehicle type, and the average vehicle speed, the timing of acceleration and deceleration, etc. may be significantly different from those of the host vehicle. Even in such a case, in the device described in Patent Document 1, while maintaining the inter-vehicle distance at a predetermined distance, driving and coasting are repeated. In that range, it is possible to give priority to energy efficiency such as fuel consumption. However, that is driving with priority given to fuel consumption within the range restricted by the driving of the preceding vehicle. Even if the host vehicle can perform more energy-efficient driving, there is a problem that it cannot perform more energy-efficient driving because it is restricted by the preceding vehicle.

[0005] The present invention has been made by focusing on the above technical problems. Even when the driving manner such as vehicle speed and the timing of acceleration and deceleration is restricted by the driving of the preceding vehicle (following vehicle) when performing following driving or platooning, by selecting the preceding vehicle (following vehicle), an object of the present invention is to provide a driving support device capable of further improving the energy efficiency such as fuel consumption or electricity cost.

Means for Solving the Problems

[0006] In order to achieve the above object, the present invention includes an engine and a motor with a power generation function as driving power sources, selects another vehicle that provides wind protection as a following vehicle, follows the following vehicle and travels, and when following the following vehicle, repeatedly performs acceleration in which the driving power source outputs driving power so that the thermal efficiency becomes optimal and coasting in which the operation of the driving power source is stopped. The driving support device for a vehicle is characterized by including: an other vehicle information acquisition unit that acquires information about the traveling state of other vehicles traveling around the own vehicle; an other vehicle acceleration / deceleration detection unit that obtains the acceleration and deceleration of other vehicles that repeatedly perform acceleration and coasting based on the acquired information; an other vehicle evaluation unit that obtains the acceleration similarity between the obtained acceleration of the other vehicle and the fuel consumption optimal acceleration of the own vehicle, and the deceleration similarity between the obtained deceleration of the other vehicle and the fuel consumption optimal deceleration of the own vehicle, and weights the acceleration similarity; and a following vehicle recommendation unit that selects, from the other vehicles traveling around the own vehicle, the other vehicle to be the following vehicle based on the weighted acceleration similarity and deceleration similarity, and notifies the driver of the own vehicle.

Effect of the Invention

[0007] In the present invention, the acceleration and deceleration of surrounding vehicles that repeatedly perform acceleration and coasting are acquired, the acceleration similarity is obtained by comparing the acceleration with the fuel consumption optimal acceleration of the own vehicle, and the deceleration similarity is obtained by comparing the acquired deceleration of the surrounding vehicle with the fuel consumption optimal deceleration of the own vehicle. In that case, the acceleration similarity is weighted. Based on the acceleration similarity and deceleration similarity thus obtained, the other vehicle to be the following vehicle is selected and notified to the driver. That is, the driver is notified of other vehicles with a high degree of similarity as the following vehicle. The degree of similarity places importance on acceleration. In other words, a vehicle whose acceleration during repeated acceleration approximates the fuel consumption optimal acceleration of the own vehicle is selected as the following vehicle. Therefore, the fuel consumption or energy efficiency of the own vehicle during so-called following driving can be further improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0009] Next, embodiments of the present invention will be described with reference to the drawings. Note that the embodiments described below are merely examples when implementing the present invention and do not limit the present invention.

[0010] The vehicle in the embodiment of the present invention is a vehicle capable of effectively performing follow - up driving known as adaptive cruise control (ACC control), etc., and an example thereof is a hybrid vehicle (HEV). The basic configuration of vehicle 1 (hereinafter sometimes referred to as the host vehicle) is shown in a block diagram in FIG. 1, and it is provided with an engine (internal combustion engine) 2 as a driving force source and a motor 3 having a power generation function. Also, it is provided with a brake 4 as in a normal vehicle. Note that devices necessary for actual driving, such as devices for steering, lighting, and direction indication, are not particularly shown in FIG. 1 but are provided in the same manner as in a normal vehicle.

[0011] The engine 2, motor 3, and brake 4 are configured to operate under electrical control, and an electronic control unit (ECU) 5 is provided for performing such control. The ECU 5 is mainly composed of a microcomputer including an arithmetic unit (arithmetic element), memory elements (RAM and ROM), and input / output devices (input / output interfaces), and is configured to perform arithmetic operations according to a predetermined program using the input data and the data stored in advance, and output the result of the arithmetic operation as a control command signal. The ECU 5 shown here is configured to control the engine 2, motor 3, and brake 4, and this may be an electronic control unit integrating an engine ECU, a motor ECU, and a brake ECU, or may be a higher-level electronic control unit that controls those ECUs individually.

[0012] In order to perform follow-up driving, it is necessary to detect the driving state or driving condition of the host vehicle 1, and it is also necessary to detect the presence of other vehicles around the host vehicle 1 and their driving states. First, as sensors for detecting the driving state and driving condition of the host vehicle 1, a wheel speed sensor 6, a longitudinal and lateral acceleration sensor 7, etc. are provided, and the signals detected by those sensors 6, 7 are input to the ECU 5. In addition, the control for driving support such as ACC control is configured to be arbitrarily selected and executed by the driver, and a driving support switch 8 is provided for instructing the execution and termination of the driving support.

[0013] In addition, a camera 10, a millimeter-wave radar (radar sensor) 11, etc. are provided to detect other vehicles (surrounding vehicles) 9 traveling around the host vehicle 1 or to acquire information about the other vehicles 9. These camera 10 and millimeter-wave radar 11 are an example of means for acquiring information about the other vehicles 9. In addition to these, the vehicle 1 may be equipped with a vehicle-to-vehicle communication system, a road-to-vehicle communication system, and even a satellite communication system (or a navigation system) that communicates with GPS satellites. According to the navigation system, in addition to being able to acquire information about the other vehicles 9 such as the vehicle speed of the surrounding other vehicles 9 and the gradient of the road on which they are traveling, it is also possible to acquire information about the host vehicle 1 such as the speed of the host vehicle 1 and the gradient of its road surface. Therefore, the information about the other vehicles 9 (surrounding vehicle information) may include information about the running state and vehicle body of the surrounding other vehicles 9 such as their position, vehicle speed, acceleration, deceleration, vehicle width, and vehicle height, and further information such as driving characteristics (power performance).

[0014] The vehicle 1 is equipped with a control system such as ACC control that performs follow-up driving while maintaining the inter-vehicle distance from the preceding vehicle at a preset predetermined distance and following the preceding vehicle. The control system is incorporated as a program in the aforementioned ECU 5, is turned on and off by the aforementioned driving support switch 8, and in the activated state, performs calculations based on information such as the vehicle speed, acceleration, or deceleration of the host vehicle 1 and information about the surrounding other vehicles 9, and is configured to control the engine 2, motor 3, or brake 4, which are the aforementioned drive power sources. The specific control may be the same as the conventionally known ACC control, or may be the same as the control for following the preceding vehicle described in the aforementioned Patent Document 1.

[0015] Such following driving is a driving mode in which the host vehicle 1 selects the immediately preceding vehicle as a following vehicle to follow, maintains the inter-vehicle distance from the following vehicle, and accelerates or decelerates the host vehicle 1 according to the acceleration and deceleration of the following vehicle, thereby reducing the acceleration and deceleration operations by the driver and assisting in driving. In addition to this, the following vehicle is controlled to provide wind protection for the host vehicle 1, and within the range of maintaining the inter-vehicle distance at a predetermined distance (the distance between a preset maximum distance and a minimum distance), acceleration and coasting are repeated to make the energy efficiency (thermal efficiency) such as fuel consumption or electricity consumption as good as possible. Such so-called fuel consumption priority inter-vehicle distance control that repeats acceleration and coasting may be the control described in the above-mentioned Patent Document 1.

[0016] In an embodiment of the present invention, when performing the above-described following control, a support control is configured to select a following vehicle that the host vehicle 1 should follow from surrounding vehicles and recommend it to the driver. The evaluation of the other vehicle 9 for the selection is performed based on whether the acceleration and deceleration related to energy efficiency are similar to the fuel consumption optimal acceleration and deceleration of the host vehicle 1 by using the information obtained by the above-described means for obtaining information about the other vehicle 9 and information such as the vehicle speed and acceleration / deceleration of the host vehicle 1. Such evaluation, the selection of the other vehicle 9 as a result, and the control of recommending the selected other vehicle 9 as a following vehicle are executed by the above-described ECU 5. Specifically, the control is executed by performing calculations according to a program prepared in advance. When the functions of the program are shown as a functional configuration, it is as shown in FIG. 2.

[0017] FIG. 2 shows, as a block diagram, a functional configuration for selecting and recommending a following vehicle among the functional configurations provided in the ECU 5, and includes an other vehicle information acquisition unit 5A that acquires information about the driving state of another vehicle 9 traveling around the host vehicle 1. Here, since the other vehicle 9 traveling around the host vehicle 1 is a vehicle that is a candidate for a following vehicle, it is a vehicle traveling in the same direction as the host vehicle 1 and is also a vehicle within a range of a relatively short distance determined in advance from the host vehicle 1. In addition, information about the other vehicle 9 can be obtained by means for acquiring external information such as a camera 10, a millimeter-wave radar 11, or a vehicle-to-vehicle communication system.

[0018] Based on the acquired information about the other vehicle 9, it includes an other vehicle acceleration / deceleration detection unit 5B that detects the acceleration and deceleration of the other vehicle 9. The acceleration and deceleration of the other vehicle 9 can be directly acquired from the other vehicle 9, but alternatively, they may be estimated from other driving information such as the position information and vehicle speed information of the other vehicle 9. Therefore, "detection" includes such estimation. By detecting the acceleration and deceleration of the other vehicle 9, it is determined whether the other vehicle 9 is repeatedly accelerating and coasting. This is because when the host vehicle 1 repeatedly accelerates and coasts to perform following driving so that the energy efficiency becomes optimal, the other vehicle that is a candidate for the following vehicle needs to repeatedly accelerate and coast. Note that acceleration is a state in which the engine 2 or the motor 3 outputs a driving force and is traveling, and it is not necessarily required that the vehicle speed is increasing. In addition, coasting is a state in which neither the engine 2 nor the motor 3 outputs a driving force to the drive wheels (not shown), and the vehicle 1 is traveling without applying the engine braking force (driving force source braking force) to the drive wheels. Therefore, as long as the driving force source is blocked from the drive wheels, the driving force source may be operating.

[0019] Based on the acceleration and deceleration of the other vehicle 9, an other vehicle evaluation unit 5C is provided that determines the degree of similarity between the other vehicle 9 and the host vehicle 1 and evaluates the other vehicle 9 based on the degree of similarity. The degree of similarity includes an acceleration similarity degree that is the degree of similarity of acceleration and a deceleration similarity degree that is the degree of similarity of deceleration associated with coasting. As an example, the acceleration similarity degree is the difference between the acceleration of the other vehicle 9 and the fuel consumption optimal acceleration of the host vehicle 1, and it is considered that the smaller the difference, the greater the degree of similarity. Similarly, as an example, the deceleration similarity degree is the difference between the deceleration of the other vehicle 9 and the fuel consumption optimal deceleration of the host vehicle 1, and it is considered that the smaller the difference, the greater the degree of similarity. These degrees of similarity may be values obtained by using the difference as an appropriate evaluation point (score). Note that the fuel consumption optimal acceleration is the acceleration that occurs when the power source operates with maximum energy efficiency. For example, in a hybrid vehicle (HEV), it is the acceleration that occurs when the engine operates at the maximum thermal efficiency point, and it can be obtained in advance as a value under predetermined conditions such as no wind and a flat road. Similarly, the fuel consumption optimal deceleration is the deceleration that occurs when the power source is operated at the point where the energy loss of the power source is minimized. For example, in an HEV, it is the deceleration that occurs in a state where the motor is neither performing power running nor regeneration during EV running with the engine stopped (coasting), and it can be obtained in advance as a value under predetermined conditions such as no wind and a flat road.

[0020] In an embodiment of the present invention, weighting is performed on the acceleration similarity degree. This is a process of emphasizing the acceleration similarity degree. When the difference regarding acceleration is small, the evaluation point (score) for acceleration is made larger (similar) than the evaluation point (score) when the difference regarding deceleration is similarly small, and conversely, when the difference regarding acceleration is large, the evaluation point (score) for acceleration is made smaller (made dissimilar) than the evaluation point (score) when the difference regarding deceleration is similarly large. This is because the improvement effect on fuel consumption or energy efficiency is greater for the energy efficiency during acceleration than for the energy efficiency during deceleration or coasting.

[0021] Furthermore, it is equipped with a following vehicle recommendation unit 5D. The above-mentioned other vehicle evaluation unit 5C performs the above evaluation for each of a plurality of other vehicles 9 traveling around the host vehicle 1, and based on the acceleration similarity and deceleration similarity of the plurality of other vehicles 9 thus obtained, selects an other vehicle 9 to be a following vehicle. Specifically, an other vehicle 9 with a large acceleration similarity and deceleration similarity is selected (picked up) as the following vehicle. In that case, the acceleration similarity is such that the difference in the acceleration on which it is based is a large similarity by weighting, and the similarity between the host vehicle 1 and the other vehicle 9 is evaluated with priority given to the degree of similarity of the acceleration. Eventually, a following vehicle is selected from among the plurality of other vehicles 9 with priority given to the degree of similarity of the acceleration.

[0022] The following vehicle recommendation unit 5D notifies the driver that the other vehicle 9 thus selected is a following vehicle that the host vehicle 1 should follow. The notification may be something that the driver can know through any of the five senses, but generally it is a notification that appeals to the sense of sight, and can be performed, for example, by displaying the following vehicle on an HMI (Human Machine Interface) 12 such as a liquid crystal monitor.

[0023] An example of the control executed by the ECU 5 having the functional configuration shown in FIG. 2 above will be described with reference to the flowchart shown in FIG. 3. The control shown in FIG. 3 is executed in a state of traveling under following running control for maintaining a vehicle-to-vehicle distance. First, for an other vehicle (surrounding vehicle) 9 traveling around the host vehicle 1, a score A for the windbreak effect is calculated (step S1). When the host vehicle 1 is hidden behind the other vehicle 9 in the traveling direction, the larger the projected area or projected shape of the other vehicle 9 in the traveling direction is than the similar projected area or projected shape of the host vehicle 1, the greater the windbreak effect of the other vehicle 9 becomes. In step S1, the score A is obtained by comparing information on such a shape (for example, overall width and vehicle height, or air resistance coefficient Cd value, etc.) in the surrounding vehicle information with information on the vehicle body shape of the host vehicle 1. The relationship between the comparison result and the score A may be prepared in the form of a predetermined map or the like. Also, the score A can be set to a larger value as the windbreak effect is greater.

[0024] Next, the host vehicle 1 calculates a score B based on the difference between the set vehicle speed in the ACC control and the vehicle speed of the other vehicle 9 (step S2). Since the set vehicle speed is input by the driver when starting the follow-up driving control and the vehicle speed of the other vehicle 9 is acquired as peripheral vehicle information, the speed difference can be obtained from these pieces of information (data). The value of the score B corresponding to the speed difference can be determined and prepared in advance in terms of design. Note that the value of the score B is set to be larger as the speed difference is smaller. This is to highly evaluate the similarity in the driving states between the other vehicle 9 and the host vehicle 1.

[0025] In the subsequent step S3, it is determined whether or not the current driving state or the forward driving state of the host vehicle 1 is a state in which the conditions for repeatedly performing optimal fuel consumption acceleration and optimal fuel consumption coasting are satisfied. Note that this step S3 may be executed following the above-described steps S1 and S2, or may be executed in parallel with their calculations. When driving at high speed or during high-load driving on a steep uphill road, etc., there is almost no merit or a small merit in improving the fuel consumption or energy efficiency even if repeated acceleration and coasting are performed. Therefore, in step S3, based on the above-described set vehicle speed and map information about the road on which the host vehicle 1 is traveling, etc., high-speed driving or high-load driving, etc. is detected and it is determined whether or not the above conditions are satisfied.

[0026] If it is affirmatively determined in step S3, the host vehicle 1 will perform a following driving in which acceleration and coasting are repeated. Therefore, it is determined whether or not another vehicle 9 around the host vehicle 1 is periodically repeating acceleration and coasting, in other words, whether or not another vehicle 9 that can be a following vehicle exists in the vicinity (step S4). The state of acceleration and deceleration (or coasting) of the surrounding other vehicle 9 can be detected based on the vehicle speed of the surrounding vehicle obtained as surrounding vehicle information or its change. Further, the repetition of acceleration and coasting means that acceleration - coasting - acceleration is repeated at least once, or coasting - acceleration - coasting is repeated at least once. In practice, in order to avoid misjudgment, it is determined that acceleration and coasting are repeated when it is detected that they are repeated a plurality of times.

[0027] If it is affirmatively determined in step S4, it means that another vehicle 9 that can be a following vehicle for the host vehicle 1 exists in the vicinity. In that case, the other vehicle 9 is evaluated by acceleration and deceleration (steps S5 and S6). The order of these evaluations is not particularly limited, and either one may be evaluated first. In the example shown in FIG. 3, first, a score C1 is calculated according to the deviation between the acceleration of the other vehicle (surrounding vehicle) 9 and the fuel - optimal acceleration of the host vehicle 1 (step S5). For example, the score C1 is preset corresponding to the difference between the acceleration of the other vehicle 9 and the fuel - optimal acceleration of the host vehicle 1 and stored in the form of a map or the like, and the score C1 corresponding to the calculated acceleration deviation (difference) is read out. Note that the fuel - optimal acceleration of the host vehicle 1 can be obtained in advance by experiments or simulations on an actual vehicle.

[0028] Similarly, score C2 is calculated for the deceleration associated with coasting (step S6). That is, score C2 is calculated according to the deviation between the deceleration of the other vehicle (surrounding vehicle) 9 and the fuel consumption optimal deceleration of the host vehicle 1. For example, score C2 is preset corresponding to the difference between the deceleration of the other vehicle 9 and the fuel consumption optimal deceleration of the host vehicle 1 and stored in the form of a map or the like, and score C2 corresponding to the calculated deviation (difference) of the decelerations is read out. Note that the fuel consumption optimal deceleration of the host vehicle 1 can be obtained in advance by experiments or simulations on an actual vehicle.

[0029] Here, regarding each of scores C1 and C2, these scores C1 and C2 are set to larger values as the deviation (difference) in acceleration or deceleration is smaller. If this is shown in a diagram, it is as shown in (A) and (B) of FIG. 4. (A) of FIG. 4 shows score C1 for acceleration, and it is set such that the difference in acceleration is "0" and the value of score C1 is the largest, and the value of score C1 becomes smaller as the absolute value of the difference in acceleration increases. Here, the "acceleration" is the rate of change of the vehicle speed in a state where the engine 2 or the motor 3, which is the driving force source, is outputting a driving force. When the driving force is small with respect to the gradient resistance and the air resistance, the vehicle speed may decrease even when the driving force source is outputting a driving force. Such a rate of change of the vehicle speed is regarded as negative (-) acceleration in (A) of FIG. 4, and the value of score C1 is set accordingly.

[0030] (B) of FIG. 4 shows the score C2 for deceleration. Similar to the score C1 for the deviation (difference) of acceleration, the score C2 is set such that the difference in deceleration is "0" and the value of the score C2 is the largest, and the value of the score C2 decreases as the absolute value of the difference in deceleration increases. Here, the "deceleration" is the rate of decrease in vehicle speed during coasting, which is the rate of change of vehicle speed in a state where neither the engine 2 nor the motor 3, which are the driving force sources, is outputting a driving force or in a state where the driving force is not transmitted to the drive wheels. Therefore, in a driving environment such as a downhill slope or a strong headwind, the vehicle speed may increase even if no driving force acts on the drive wheels. In FIG. 4(B), such a rate of change of vehicle speed is regarded as a negative (-) deceleration, and the value of the score C2 is set accordingly.

[0031] Furthermore, weighting is applied to the score C1 for acceleration. As can be seen by comparing (A) and (B) of FIG. 4, the maximum value of the score C1 for acceleration is made larger than the maximum value of the score C2 for deceleration. Also, the slope of the straight line showing the relationship between the deviation (difference) of acceleration and the value of the score C1 is larger than the slope of the straight line showing the relationship between the deviation (difference) of deceleration and the value of the score C2. That is, the value of the score C1 when the deviation (difference) of acceleration is small is larger than the value of the score C2 when the deviation (difference) of deceleration is small, and the value of the score C1 when the deviation (difference) of acceleration is large is smaller than the value of the score C2 when the deviation (difference) of deceleration is large. If the deviation (difference) of acceleration or deceleration is small, it means that the degree of similarity in the acceleration and coasting states, such as the degree and timing of acceleration and deceleration, between the host vehicle 1 and the other vehicle 9 is large. Therefore, by weighting the score C1 as described above, acceleration is preferentially adopted in the evaluation or determination of the degree of similarity between the host vehicle 1 and the other vehicle 9.

[0032] Obtain the product of the four scores A, B, C1, and C2 calculated as described above, select the other vehicle 9 for which this value is the largest as the following vehicle, and inform the driver (step S7). As described above, the score A becomes a larger value as the windbreak effect is greater, the score B becomes a larger value as the vehicle speeds are more similar, and further, the scores C1 and C2 become larger values as the acceleration and deceleration during repeated acceleration and coasting are closer to the acceleration and deceleration at which the fuel consumption is optimal. Therefore, the other vehicle 9 for which the product of these four scores A, B, C1, and C2 is large is the vehicle that can most effectively reduce the energy consumption when the host vehicle 1 follows. Accordingly, it is decided to select such an other vehicle 9 as the following vehicle. In that case, in the evaluation of the similarity degree of the acceleration and deceleration of the other vehicle 9 with respect to the host vehicle 1, since the configuration is such that the similarity degree of the acceleration is prioritized, the reduction effect of the consumed energy such as the fuel consumption or electricity cost when the host vehicle 1 follows can be increased.

[0033] On the other hand, when a negative determination is made in step S3 described above due to traveling at a high vehicle speed or traveling under a high load, etc., and when a negative determination is made in step S4 because the other vehicle 9 that repeatedly accelerates and coasts does not exist around the host vehicle 1, the other vehicle 9 is evaluated based on the vehicle speed stability. Specifically, the value of the score C that is set to become a larger value as the vehicle speed is more stable is calculated for each of the surrounding other vehicles 9 (step S8). Then, proceed to step S7, obtain the product of the calculated scores A, B, and C, select the other vehicle 9 for which this value is large as the following vehicle, and inform the driver.

[0034] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified and implemented within the scope of achieving the object of the present invention. For example, in the above-described embodiments, the similarity degree of the acceleration and deceleration is represented by a score, but the present invention is not limited to this. Instead, the fuel consumption rate or energy efficiency during acceleration and deceleration of the other vehicle may be calculated based on the surrounding vehicle information, and the similarity degree may be obtained by comparing this value with the optimal fuel consumption or maximum energy efficiency value during acceleration and deceleration of the host vehicle.

Description of Symbols

[0035] 1 Vehicle (own vehicle) 2 Engine 3 Motor 4 Brake 5 Electronic Control Unit (ECU) 5A Other vehicle information acquisition unit 5B Other vehicle acceleration detection unit 5C Other vehicle evaluation unit 5D Following vehicle recommendation unit 6 Wheel speed sensor 7 Longitudinal and lateral acceleration sensor 8 Driving support switch 9 Other vehicle (surrounding vehicle) 10 Camera 11 Millimeter-wave radar 12 HMI

Claims

【Claim 1】 A vehicle driving support device that includes an engine and a motor with a power generation function as driving power sources, selects another vehicle that serves as a windbreak as a following vehicle, follows and travels behind the following vehicle, and repeatedly performs acceleration in which the driving power sources output driving power and coasting in which the operation of the driving power sources is stopped so that the thermal efficiency becomes optimal when traveling behind the following vehicle, comprising: An other vehicle information acquisition unit that acquires information about the driving state of other vehicles traveling around the host vehicle; An other vehicle acceleration / deceleration detection unit that obtains the acceleration and deceleration of other vehicles that repeatedly perform acceleration and coasting based on the acquired information; An other vehicle evaluation unit that obtains the acceleration similarity between the acceleration of the other vehicle obtained and the fuel efficiency optimal acceleration of the host vehicle, and the deceleration similarity between the deceleration of the other vehicle obtained and the fuel efficiency optimal deceleration of the host vehicle, and weights the acceleration similarity; A following vehicle recommendation unit that selects, from the other vehicles traveling around the host vehicle, the other vehicle to be the following vehicle based on the weighted acceleration similarity and deceleration similarity, and notifies the driver of the host vehicle; A vehicle driving support device, characterized by comprising the above.

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