Driving assistance device, driving assistance method, and program

Abstract

This reduces the likelihood of drivers performing follow-up maneuvers in situations where it is undesirable or unrecommended to do so, such as when following a vehicle that has a high air resistance reduction effect. [Solution] The driver assistance device displays a follow-recommended image that recommends the vehicle following a follow-recommended vehicle that is traveling ahead of the vehicle and has an air resistance reduction effect of a predetermined value or more that reduces the air resistance experienced by the vehicle. If a non-recommended condition is met, which is when it is not recommended to perform driving operations to follow the follow-recommended vehicle, the follow-recommended image is not displayed.

Description

Technical Field

[0001] The present invention relates to a driving support device that displays, on a display device, a fuel efficiency improvement image for improving the fuel efficiency of the own vehicle, a driving support method in which a computer mounted on the own vehicle displays the fuel efficiency improvement image, and a program that causes a computer mounted on the own vehicle to display the fuel efficiency improvement image.

Background Art

[0002] Conventionally, driving support devices configured to display a fuel efficiency improvement image for improving the fuel efficiency of a vehicle on a display device of the vehicle are known. For example, the driving support device described in Patent Document 1 (hereinafter referred to as "conventional device") acquires, for a plurality of preceding vehicles, a potential value that is the maximum value of the air resistance reduction effect of the vehicle expected from following travel. The conventional device displays, as driving support images for each of the plurality of preceding vehicles, a vehicle icon indicating the preceding vehicle, and an effect graphic representing the degree of the potential value of each individual preceding vehicle relative to the maximum effect value common among the plurality of preceding vehicles.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

[0004] When the conventional device displays the above driving support image, the possibility that the driver performs a driving operation (hereinafter referred to as "following operation") for causing the vehicle to follow behind a preceding vehicle with a high air resistance reduction effect increases. The following operation is, for example, an acceleration operation or the like that accelerates the own vehicle to approach the preceding vehicle. The conventional device displays the above driving support image even under a non-recommended situation, which is a situation where the risk of collision with an object increases when the following operation is performed. For this reason, the conventional device cannot reduce the possibility that the following operation is performed under the non-recommended situation.

[0005] This invention was made to address the aforementioned problems. Specifically, one of the objectives of this invention is to provide a driver assistance device that can reduce the possibility of follow-up operation being performed under undesirable conditions.

[0006] The driver assistance device of the present invention (hereinafter referred to as "the device of the present invention") is configured to display fuel efficiency improvement images on the vehicle's display device in order to improve the vehicle's fuel efficiency. The aforementioned driving support device, A follow-recommended image (56) is displayed as the fuel efficiency improvement image, which recommends that the vehicle follow behind a follow-recommended vehicle that is traveling ahead of the vehicle and has an air resistance reduction effect of a predetermined value or more that reduces the air resistance experienced by the vehicle (steps 540, 545). If the discouragement condition is met (step 525 "No", step 530 "Yes"), which is when it is not recommended to perform the driving operation to follow behind the recommended vehicle, the recommended follow image will not be displayed. It is structured in this way.

[0007] According to the present invention, if the unrecommended conditions are met, the recommended follow image will not be displayed. Therefore, the present invention can reduce the possibility that driving operations (follow operations) to follow the vehicle behind the recommended follow vehicle will be performed when the unrecommended conditions are met.

[0008] In one embodiment of the apparatus of the present invention, The aforementioned driving support device, If at least one of the following conditions is met, the discouragement condition is determined to be met: firstly, the collision risk representing the possibility of the vehicle colliding with the object is greater than or equal to the threshold risk (step 525 "No"), and secondly, the operation performed by the driver of the vehicle on the vehicle's accelerator control satisfies predetermined operating conditions (step 530 "Yes"). It is structured in this way.

[0009] If the first condition is met and a follow-recommended image is displayed, and the driver performs a follow operation, it is highly likely that the risk of collision will increase further. If the second condition is met, it is highly likely that the vehicle is accelerating rapidly. In such a case, if a follow-recommended image is displayed and the driver performs a follow operation, it is highly likely that the vehicle will accelerate even further. Therefore, it is highly likely that the risk of collision will increase. According to this embodiment, if at least one of the first and second conditions is met, the follow-recommended image is not displayed, so the possibility of a follow operation being performed can be reduced, and the possibility of an increased risk of collision can be reduced.

[0010] In the above embodiment, The aforementioned driving support device, The system performs driving support control to either drive the vehicle at a preset speed, or to maintain a preset distance between the vehicle and a preceding vehicle traveling in the same lane as the vehicle, and drive the vehicle. If the second condition is met while the aforementioned driving support control is being executed, the driving support control is interrupted, and the vehicle is driven with the driving force corresponding to the manipulated amount. If the second condition is met (step 530 "Yes"), it is determined that the deprecation condition is met. It is structured in this way.

[0011] If the second condition is met while driving assistance control is being executed, accelerator override occurs. That is, driving assistance control is interrupted and the vehicle moves with a driving force corresponding to the amount of input to the accelerator control. During such accelerator override, the vehicle is likely to be accelerating rapidly. If a follow operation is performed in such a situation, the vehicle is likely to accelerate even further. Therefore, the risk of collision is likely to increase. In this embodiment, if the second condition is met, the follow recommendation image is not displayed, so the possibility of a follow operation being performed can be reduced, and the possibility of an increased risk of collision can be reduced.

[0012] In one embodiment of the apparatus of the present invention, The aforementioned driving support device, In addition to the recommended follow image, a fuel efficiency status image (58) representing the current level of fuel efficiency reduction of the vehicle, obtained based on the air resistance reduction effect of a preceding vehicle traveling in front of the vehicle in the same lane, is also displayed as a fuel efficiency improvement image (steps 540, 550). It is structured in this way.

[0013] By viewing the fuel consumption status image, the driver can understand the current level of fuel efficiency improvement of their vehicle. This increases the likelihood that the driver will perform driving maneuvers that will improve the vehicle's fuel efficiency, thereby increasing the chances of improving the vehicle's fuel efficiency.

[0014] In one embodiment of the apparatus of the present invention, The driving assistance device is configured to acquire the air resistance reduction effect based at least on the projected area of ​​the rear of another vehicle traveling in front of the vehicle (steps 605, 610, and 735).

[0015] Since a larger projected area results in a greater air resistance reduction effect, this embodiment allows for a more accurate acquisition of the air resistance reduction effect.

[0016] In one embodiment of the apparatus of the present invention, The aforementioned driving support device, If the adjacent vehicle traveling ahead of the vehicle and in the adjacent lane adjacent to the vehicle's lane is the recommended vehicle to follow (step 535), it is determined whether the vehicle can change lanes to the adjacent lane (step 550), If the vehicle in question cannot change lanes to the adjacent lane (Step 550 "No"), the system determines that the discouragement condition has been met and does not display the recommended follow image of the adjacent vehicle. It is structured in this way.

[0017] If a follow recommendation image for an adjacent vehicle is displayed even when a lane change is not possible, the driver may perform a driving operation for lane change as a follow operation. When such a follow operation is performed, the risk of collision may increase. According to this aspect, when a lane change is not possible, the follow recommendation image for an adjacent vehicle is not displayed, so the possibility that a driving operation for lane change is performed as a follow operation can be reduced. As a result, the possibility of an increased collision risk can be reduced.

[0018] In the above aspect, The driving support device When there is a preceding vehicle traveling in the own lane and having an air resistance reduction effect equal to or greater than a predetermined value, and an adjacent vehicle traveling in the adjacent lane and having an air resistance reduction effect equal to or greater than the predetermined value (Step 615 "Yes"), the vehicle with the greater air resistance reduction effect is identified as the recommended follow vehicle (Step 620), is configured as follows.

[0019] According to this aspect, the follow recommendation image for the preceding vehicle and the follow recommendation image for the adjacent vehicle are not displayed at the same time. This reduces the possibility that the driver will be confused about whether the vehicle to be followed behind is the preceding vehicle or the adjacent vehicle.

[0020] In the above aspect, The driving support device When there is a preceding vehicle traveling in the own lane and having an air resistance reduction effect equal to or greater than a predetermined value, and an adjacent vehicle traveling in the adjacent lane and having an air resistance reduction effect equal to or greater than the predetermined value, and the air resistance reduction effect of the adjacent vehicle is greater than that of the preceding vehicle, it is determined whether or not the own vehicle can change lane to the adjacent lane (Step 550), When the own vehicle cannot change lane to the adjacent lane (Step 550 "No"), the preceding vehicle having the air resistance reduction effect equal to or greater than the predetermined value is identified as the recommended follow vehicle, and the follow recommendation image for the preceding vehicle is displayed. is configured as follows.

[0021] If the recommended following image suddenly disappears because the vehicle is unable to change lanes to an adjacent lane, the driver may feel uneasy. According to this embodiment, when a lane change is not possible, a recommended following image of a preceding vehicle with an air resistance reduction effect of a predetermined value or higher is displayed, thereby reducing the possibility of the driver feeling uneasy.

[0022] The driving assistance method of the present invention involves a computer installed in the vehicle displaying fuel efficiency improvement images on the vehicle's display device in order to improve the vehicle's fuel efficiency. The aforementioned driving assistance method is The computer displays a recommended follow image (56) as the fuel efficiency improvement image, which recommends that the vehicle follow a recommended follow vehicle that is traveling ahead of the vehicle and has an air resistance reduction effect of a predetermined value or more that reduces the air resistance experienced by the vehicle, as the fuel efficiency improvement image (steps 540, 545). If the computer does not recommend performing driving operations to follow the recommended vehicle, and the non-recommendation conditions are met (step 525 "No", step 530 "Yes"), the step of not displaying the recommended follow image is performed. Includes.

[0023] The program of the present invention causes a computer installed in the vehicle to display fuel efficiency improvement images on the vehicle's display device in order to improve the vehicle's fuel efficiency. The program is installed on the computer. Steps (540, 545) include displaying a recommended follow image (56) as the fuel efficiency improvement image, which recommends that the vehicle follow a recommended follow vehicle that is traveling ahead of the vehicle and has an air resistance reduction effect of a predetermined value or more that reduces the air resistance experienced by the vehicle, If the discouragement condition is met, which is when it is not recommended to perform driving operations to follow behind the recommended vehicle (step 525 "No", step 530 "Yes"), the step of not displaying the recommended follow image is performed. Make it run.

[0024] According to the above-described driving assistance method and program, the possibility of follow-up operation being performed when undesirable conditions are met can be reduced. [Brief explanation of the drawing]

[0025] [Figure 1] This is a schematic system configuration diagram of a driver assistance device according to an embodiment of the present invention. [Figure 2] This is an explanatory diagram for normal constant speed control and eco-constant speed control. [Figure 3] This diagram illustrates the relationship between following distance, set distance, and the upper limit of the distance range. [Figure 4] This is an explanatory diagram of the surrounding environment screen. [Figure 5] Figure 1 is a flowchart of the peripheral environment screen display routine executed by the CPU of the ECU. [Figure 6] Figure 1 is a flowchart of the follow-recommended vehicle identification subroutine executed by the ECU's CPU. [Figure 7] Figure 1 is a flowchart of the fuel efficiency improvement level determination subroutine executed by the ECU's CPU. [Figure 8] Figure 1 is a flowchart of the alarm routine executed by the ECU's CPU. [Modes for carrying out the invention]

[0026] An embodiment of the present invention, the driver assistance device 10 (hereinafter referred to as "the device 10"), is applied to the vehicle VA and includes the ECU 20 shown in Figure 1. The ECU 20 is an electronic control device that mainly consists of a microcomputer. The ECU 20 may also be referred to as a control unit, controller, or computer. The microcomputer includes a CPU (processor), ROM, RAM, and interface (I / F), etc. The functions realized by the ECU 20 may be realized by multiple ECUs.

[0027] The ECU 20 includes a front camera 22, a millimeter-wave radar 24, a driving support control unit 26, an eco-driving control unit 28, a vehicle speed sensor 30, and an acceleration sensor 32.

[0028] The forward camera 22 acquires forward image data by photographing the area in front of the vehicle VA. The millimeter-wave radar 24 receives reflected waves from millimeter waves transmitted in front of the vehicle VA that are reflected by an object, and acquires forward radar data. The radar data contains data on the position of the object relative to the vehicle VA and the relative velocity Vr of the object relative to the vehicle VA.

[0029] The ECU 20 acquires forward image data from the forward camera 22 and radar data from the millimeter-wave radar 24. Based on the forward image data and radar data, the ECU 20 recognizes objects in front of the vehicle VA.

[0030] The driving support control unit 26 is a device operated by the driver and includes switches and buttons. The driving support control unit 26 is located near the steering wheel of the vehicle VA. The driving support control unit 26 includes a driving support selection switch, a vehicle speed setting switch, a vehicle speed increase button, a vehicle speed decrease button, and a distance setting button.

[0031] When the driver operates the driving assistance selection switch while the driving assistance control described later is not in operation, the driving assistance control unit 26 transmits a signal to the ECU 20. Upon receiving this signal, the ECU 20 determines that the driver is requesting the execution of the driving assistance control. On the other hand, when the driver operates the driving assistance selection switch while the driving assistance control is in operation, the driving assistance control unit 26 transmits a signal to the ECU 20. Upon receiving this signal, the ECU 20 determines that the driver is requesting the termination of the driving assistance control.

[0032] When the vehicle speed setting switch is operated by the driver while driving assistance control is being performed, the driving assistance control unit 26 transmits a signal to the ECU 20. Upon receiving this signal, the ECU 20 sets the vehicle speed Vs of the vehicle VA at that time as the set vehicle speed Vset for the driving assistance control.

[0033] When the driver operates the vehicle speed increase button while driving assistance control is in operation, the driving assistance control unit 26 sends a signal to the ECU 20. Upon receiving this signal, the ECU 20 increases the set vehicle speed Vset. Conversely, when the driver operates the vehicle speed decrease button while driving assistance control is in operation, the driving assistance control unit 26 sends a signal to the ECU 20. Upon receiving this signal, the ECU 20 decreases the set vehicle speed Vset.

[0034] When the driver operates the distance setting button while driving assistance control is in operation, the driving assistance control unit 26 sends a signal to the ECU 20. Upon receiving this signal, the ECU 20 changes the set distance Dset, which will be described later.

[0035] The eco-driving control unit 28 is a device operated by the driver and includes switches and buttons. The eco-driving control unit 28 is located near the steering wheel of the vehicle VA. When the eco-driving control unit 28, which is in the OFF position, is operated, it moves to the ON position. When the eco-driving control unit 28 is in the ON position, it transmits a signal to the ECU 20. Upon receiving this signal, the ECU 20 determines that the driver is requesting the execution of the eco-driving control described later.

[0036] When the eco-driving control unit 28, which is in the ON position, is operated, the eco-driving control unit 28 moves to the OFF position. When the eco-driving control unit 28 moves to the OFF position, it transmits a signal to the ECU 20. When the ECU 20 receives this signal, it determines that the driver has not requested the execution of the eco-driving control described later.

[0037] The vehicle speed sensor 30 measures the vehicle speed Vs. The acceleration sensor 32 measures the acceleration G of the vehicle VA. The ECU 20 acquires the measured values ​​from the vehicle speed sensor 30 and the acceleration sensor 32.

[0038] The drive unit 40 outputs a driving force to propel the vehicle VA. For example, the drive unit 40 is an internal combustion engine and / or a motor. The ECU 20 controls the driving force output by the drive unit 40 by controlling the operation of the drive unit 40. The braking unit 42 is a device that outputs a braking force to brake the vehicle VA. The ECU 20 controls the braking force output by the braking unit 42 by controlling the operation of the braking unit 42. The display device 44 is positioned where the driver can see it.

[0039] <Driving support control> The ECU20 executes driving assistance control when requested. Driving assistance control includes normal driving assistance control and eco driving assistance control. Normal driving assistance control includes normal constant speed control and normal follow control, while eco driving assistance control includes eco constant speed control and eco follow control. Eco driving assistance control is a more energy-efficient driving control than normal driving assistance control. The driver requests the execution of eco driving assistance control when they want to improve the fuel efficiency of their vehicle (VA).

[0040] <Normal driving support control> If driving assistance control is requested but eco-driving assistance control is not, the ECU20 executes normal driving assistance control. Specifically, the ECU20 determines whether or not a following lead vehicle VB (see Figure 3) exists. If no following lead vehicle VB exists, the ECU20 executes normal constant speed control as normal driving assistance control. On the other hand, if a following lead vehicle VB exists, the ECU20 executes normal following control as normal driving assistance control.

[0041] The ECU20 identifies other vehicles that meet the following conditions S1 and S2 as the following lead vehicle VB. Condition S1: The vehicle is traveling in the same lane as vehicle VA, and is traveling in front of vehicle VA. Condition S2: The distance D between the vehicle VA and the other vehicle (see Figure 3) is less than or equal to the threshold distance.

[0042] <Normal constant speed control> In normal constant-speed control, the ECU 20 accelerates or decelerates the vehicle VA so that the vehicle speed Vs is maintained at the set vehicle speed Vset. As shown by the solid line in Figure 2, the ECU 20 accelerates the vehicle VA when the vehicle speed Vs falls below the set vehicle speed Vset, and decelerates the vehicle VA when the vehicle speed Vs exceeds the set vehicle speed Vset. More specifically, the ECU 20 obtains a required acceleration Greq such that the speed at which the vehicle speed Vs converges to the set vehicle speed Vset is equal to or greater than a predetermined speed, and obtains a required braking force or required driving force to achieve the required acceleration Greq. The ECU 20 then controls the drive unit 40 and / or braking unit 42 so that the required braking force or required driving force is output.

[0043] <Normal tracking control> In normal adaptive cruise control, the ECU 20 accelerates or decelerates its own vehicle VA so that the distance D between vehicles shown in Figure 3 is maintained at a set distance Dset. The ECU 20 accelerates its own vehicle VA when the distance D between vehicles becomes longer than the set distance Dset, and decelerates its own vehicle VA when the distance D between vehicles becomes shorter than the set distance Dset. More specifically, the ECU 20 obtains a required acceleration Greq such that the speed at which the distance D between vehicles converges to the set distance Dset is equal to or greater than a predetermined speed, and obtains a required braking force or required driving force to achieve the required acceleration Greq. The ECU 20 then controls the drive unit 40 and / or braking unit 42 so that the required braking force or required driving force is output.

[0044] In normal constant-speed control and normal follow-up control, the control that controls the drive unit 40 and / or brake unit 42 so that the required driving force to achieve the required acceleration Greq is output is referred to as "normal acceleration control," and the control that controls the drive unit 40 and / or brake unit 42 so that the required braking force to achieve the required acceleration Greq is output is referred to as "normal deceleration control."

[0045] <Eco-driving support control> If driving assistance control is requested and eco-driving assistance control is also requested, the ECU20 executes eco-driving assistance control. Specifically, if there is no following preceding vehicle VB, the ECU20 executes eco-constant speed control as eco-driving assistance control, and if there is a following preceding vehicle VB, it executes eco-following control as eco-driving assistance control.

[0046] <Eco constant speed control> In eco-constant speed control, the ECU20 accelerates or decelerates the vehicle VA so that the vehicle speed Vs is maintained within the "vehicle speed range where the set vehicle speed Vset is set to the upper limit Vmax" (controlling the acceleration of the vehicle VA). As shown by the dotted line in Figure 2, the ECU20 accelerates the vehicle VA when the vehicle speed Vs falls below the lower limit Vmin of the vehicle speed range, and decelerates the vehicle VA when the vehicle speed Vs exceeds the upper limit Vmax (set vehicle speed Vset) of the vehicle speed range.

[0047] When accelerating the vehicle VA using eco constant speed control, the ECU 20 obtains the acceleration G, which is the required acceleration Greq, based on the vehicle speed Vs, such that the energy efficiency of the drive unit 40 when it outputs driving force is equal to or greater than a predetermined efficiency. The ECU 20 controls the drive unit 40 and / or the brake unit 42 so that the required driving force is output to achieve the required acceleration Greq.

[0048] When the vehicle VA is decelerated using eco-constant speed control, the ECU20 acquires the acceleration G at which the required driving force becomes zero as the required acceleration Greq. As a result, when the vehicle VA is decelerated using eco-constant speed control, the vehicle VA will coast. Hereafter, this type of deceleration will be referred to as "coasting deceleration".

[0049] Furthermore, if the drive unit 40 has a motor, the ECU 20 may decelerate the vehicle VA using eco constant speed control by rotating the motor with the vehicle VA's driving energy to regenerate power and thereby decelerate the vehicle VA. Hereinafter, this type of deceleration will be referred to as "regenerative deceleration."

[0050] <Eco-friendly tracking control> In eco-following control, the ECU20 determines the distance range (see Figure 3) used to decide whether to accelerate or decelerate the vehicle VA. In this example, the lower limit of the distance range, Dmin, is set to the set distance Dset. The ECU20 accelerates the vehicle VA when the distance D between vehicles becomes longer than the upper limit of the distance range, Dmax, and decelerates the vehicle VA when the distance D between vehicles becomes shorter than the lower limit of the distance range, Dmin (set distance Dset). Note that the acceleration and deceleration of the vehicle VA in eco-following control are performed in the same manner as the acceleration and deceleration of the vehicle VA in eco-constant speed control.

[0051] In eco-constant speed control and eco-following control, the control that accelerates the vehicle's VA is called "eco-acceleration control," and the control that decelerates the vehicle's VA is called "eco-deceleration control." In eco-acceleration control, the vehicle's VA accelerates with a smaller acceleration than in normal acceleration control. The acceleration of the vehicle's VA in eco-acceleration control is sometimes called "suppressed acceleration." In eco-deceleration control, the vehicle's VA decelerates with a smaller deceleration than in normal deceleration control.

[0052] (Summary of operation) When driving assistance control is requested, the ECU 20 displays the surrounding environment screen 50 on the display device 44. The surrounding environment screen 50 displays a lane image 52, an image of the current vehicle 54a, an image of a preceding vehicle 54b, and an image of an adjacent vehicle 54c.

[0053] The lane image 52 is an image of the lane in which the vehicle VA is traveling. The ECU 20 extracts the white lines from the forward image data and generates the lane image 52 based on the position of the white lines relative to the vehicle SV.

[0054] The vehicle image 54a represents the vehicle VA. The ECU 20 displays the pre-prepared vehicle image 54a in a predetermined position.

[0055] The preceding vehicle image 54b represents a preceding vehicle traveling in front of the vehicle VA in the vehicle's own lane. The preceding vehicle includes not only the following preceding vehicle but also other vehicles whose following distance D is greater than the threshold distance mentioned above. The ECU 20 generates the preceding vehicle image 54b based on the image of the preceding vehicle included in the forward image data. The ECU 20 then displays the preceding vehicle image 54b at a position corresponding to the position of the preceding vehicle relative to the vehicle VA, which is determined based on the forward image data and radar data.

[0056] The adjacent vehicle image 54c represents an adjacent vehicle. An adjacent vehicle is another vehicle traveling in front of the vehicle VA in an adjacent lane adjacent to the vehicle's own lane. The ECU 20 generates the adjacent vehicle image 54c based on the image of the adjacent vehicle included in the forward image data. The ECU 20 then displays the adjacent vehicle image 54c at a position corresponding to the "position of the adjacent vehicle relative to the vehicle VA, which is identified based on the forward image data and radar data."

[0057] When driving assistance control is requested and eco-driving assistance control is also requested, the ECU 20 displays fuel efficiency improvement images on the surrounding environment screen 50 to improve the fuel efficiency of the vehicle VA. More specifically, the ECU 20 displays the follow recommendation image 56 and the fuel efficiency status image 58 as fuel efficiency improvement images.

[0058] The recommended follow image 56 is an image that recommends that the vehicle VA follows a vehicle that is traveling ahead of it and whose air resistance reduction effect is above a predetermined value. For example, the recommended follow image 56 is displayed superimposed on the image of the recommended follow vehicle. In the example shown in Figure 4, the preceding vehicle is identified as the recommended follow vehicle, and the recommended follow image 56 is displayed superimposed on the image of the preceding vehicle 54b. Note that the recommended follow image 56 does not necessarily have to be displayed superimposed on the image of the recommended follow vehicle; it is sufficient if it is displayed in conjunction with the recommended follow image (near the image of the recommended follow vehicle). How the ECU 20 acquires the air resistance reduction effect will be described later.

[0059] The fuel efficiency status image 58 represents the level at which the current vehicle VA's fuel efficiency can be improved (hereinafter referred to as the "fuel efficiency improvement level"). In this embodiment, the fuel efficiency status image 58 represents the fuel efficiency improvement level in five stages from "0" to "4". The higher the fuel efficiency improvement level, the greater the improvement in the vehicle VA's fuel efficiency. How the ECU 20 acquires the fuel efficiency improvement level will be described later.

[0060] The display of the recommended follow image 56 encourages the driver to have their vehicle VA follow behind a vehicle with high air resistance reduction. This improves the fuel efficiency of the vehicle VA. Furthermore, the display of the fuel efficiency status image 58 allows the driver to understand the current level of fuel efficiency improvement. Thus, the fuel efficiency status image 58 motivates the driver to continue using eco-driving control.

[0061] When an image showing improved fuel efficiency is displayed, drivers are more likely to perform a "follow-the-leader operation," which is a driving operation to drive behind a recommended vehicle, even if it is not recommended. For example, situations where the risk of the vehicle VA colliding with an object is above a threshold risk, and situations where the vehicle VA is likely to be accelerating rapidly, are situations in which the driver is not recommended to perform a follow-the-leader operation.

[0062] Therefore, in this embodiment, the ECU 20 prohibits the display of the fuel efficiency improvement image when a discouragement condition is met, which is when it is not recommended for the driver to perform follow-up operations. This reduces the possibility that the driver will perform follow-up operations in situations where it is not recommended.

[0063] (Specific operation) The CPU of ECU20 executes the routines shown in the flowcharts in Figures 5 and 8 at predetermined intervals.

[0064] <Routine for displaying the surrounding environment screen> When the appropriate time arrives, the CPU starts processing from step 500 in Figure 5, and the processing proceeds to step 505. In step 505, the CPU determines whether or not driving assistance control is requested.

[0065] If driving assistance control is not requested, the CPU determines "No" in step 505, and processing proceeds to step 595. In step 595, the CPU terminates this routine. As a result, if driving assistance control is not requested, the surrounding environment screen 50 is not displayed.

[0066] If driving assistance control is requested, the CPU determines "Yes" in step 505, and the process proceeds to step 510. In step 510, the CPU determines whether or not eco-driving assistance control is requested.

[0067] If eco-driving support control is requested, the CPU determines "Yes" in step 510 and executes steps 515 to 525.

[0068] Step 515: The CPU executes a follow-recommended vehicle identification subroutine to identify the vehicle recommended for following. Details of the follow-recommended vehicle identification subroutine will be described later. Step 520: The CPU executes a fuel efficiency improvement level identification subroutine to determine the level of fuel efficiency improvement. Details of the fuel efficiency improvement level identification subroutine will be described later.

[0069] Step 525: The CPU determines whether the alarm flag Xal is "0". The warning flag Xal is set to "1" when the ECU20 issues a warning, and to "0" when the ECU20 does not issue a warning. The warning flag Xal is set to "0" during the initialization routine. The initialization routine is executed by the CPU when the ignition key switch (not shown) of the vehicle VA is changed from the off position to the on position. The ECU20 issues a warning if the collision risk exceeds a threshold risk. Details of this will be described later.

[0070] If the alarm flag Xal is "0", the CPU determines "Yes" in step 525, and the process proceeds to step 530. In step 530, the CPU determines whether the driver is performing an accelerator override operation.

[0071] The CPU determines that the driver is performing an accelerator override operation during the period between the fulfillment of both conditions A1 and A2 and the fulfillment of condition A3. Condition A1: The accelerator pedal input is equal to or greater than the first threshold amount. Condition A2: The accelerator pedal operation speed is equal to or greater than the threshold speed. Accelerator operation amount represents the amount the driver presses the accelerator pedal. Accelerator operation speed represents the rate of change per unit time of the driver's accelerator pedal depression. The accelerator pedal is sometimes referred to as the "acceleration control unit." Condition A3: The accelerator pedal input is less than or equal to the "second threshold amount, which is smaller than the first threshold amount".

[0072] If the driver performs an accelerator override operation, the ECU 20 performs the accelerator override. Specifically, the ECU 20 interrupts normal driving support control or eco driving support control and controls the drive unit 40 and / or brake unit 42 so that the required driving force is output according to the amount of accelerator operation. For this reason, if the driver performs an accelerator override operation, there is a high possibility that the vehicle VA will accelerate rapidly.

[0073] If the warning flag Xal is "0" and the driver has not performed an accelerator override operation, the discouraged condition is not met.

[0074] In step 530, if the driver has not performed an accelerator override operation, the CPU determines "No" in step 530, and the process proceeds to step 535. In step 535, the CPU determines whether the recommended following vehicle is an adjacent vehicle.

[0075] If the recommended vehicle to follow is not an adjacent vehicle (i.e., the recommended vehicle to follow is a preceding vehicle), the CPU determines "No" in step 535 and executes steps 540 and 545.

[0076] Step 540: The CPU embeds the recommended follow image 56 into the image of the recommended follow vehicle, and embeds the fuel consumption status image 58 below the image of the own vehicle 54a. Step 545: The CPU displays the surrounding environment screen 50 on the display device 44. In detail, the CPU generates a surrounding environment screen 50 by positioning the preceding vehicle image 54b and the adjacent vehicle image 54c relative to the vehicle image 54a based on the position of the preceding vehicle relative to the vehicle's VA, and displays the surrounding environment screen 50 on the display device 44. The process then proceeds to step 595.

[0077] If the alarm flag Xal is "1" when the process proceeds to step 525, the deprecation condition is met. In this case, the CPU determines "No" in step 525, and the process proceeds to step 545. As a result, step 540 is not executed, and the fuel efficiency improvement images (follow-recommended image 56 and fuel efficiency status image 58) are not displayed on the surrounding environment screen 50.

[0078] If the driver performs an accelerator override operation when the process proceeds to step 530, the normal driving support control or eco driving support control will be interrupted as described above, increasing the likelihood of the vehicle VA accelerating rapidly. In such a case, the risk of collision increases if a follow operation is performed, so in this embodiment, the CPU determines that the undesirable condition is met. In this case, the CPU determines "No" in step 530, and the process proceeds to step 545. As a result, the fuel efficiency improvement image is not displayed on the surrounding environment screen 50.

[0079] If the recommended vehicle to follow is an adjacent vehicle when the process proceeds to step 535, the CPU determines "Yes" in step 535, and the process proceeds to step 550. In step 550, the CPU determines, based on forward image data and radar data, whether the vehicle VA can change lanes into the adjacent lane where the recommended vehicle to follow is traveling.

[0080] If the following recommendation image 56 is displayed when the vehicle VA is unable to change lanes to an adjacent lane, the driver is more likely to change lanes. Therefore, if the vehicle VA is unable to change lanes to an adjacent lane, the non-recommendation condition is met. In this case, the CPU determines "No" in step 550, and the process proceeds to step 545. As a result, the fuel efficiency improvement image is not displayed on the surrounding environment screen 50.

[0081] On the other hand, if the vehicle VA can change lanes to an adjacent vehicle, the discouraged condition is not met. In this case, the CPU determines "Yes" in step 550, and the process proceeds to step 540. As a result, the fuel efficiency improvement image is displayed on the surrounding environment screen 50.

[0082] If eco-driving support control is not requested when the process proceeds to step 510, the CPU determines "No" in step 540, and the process proceeds to step 545. As a result, the fuel efficiency improvement image is not displayed on the surrounding environment screen 50.

[0083] <Subroutine for identifying recommended following vehicles> If the process proceeds to step 515, the CPU starts processing from step 600 as shown in Figure 6 and executes steps 605 to 615.

[0084] Step 605: The CPU identifies another vehicle (preceding vehicle) traveling ahead of its own vehicle VA in its own lane as a candidate vehicle if it meets the candidate vehicle conditions. In detail, the CPU determines that another vehicle meets the candidate criteria if it also meets the following conditions C1 through C3. Condition C1: The projected area of ​​other vehicles is greater than or equal to the threshold area. The projected area is the area behind the other vehicle. The CPU obtains the projected area based on the image of the other vehicle included in the forward-facing image data. Condition C2: The speed of other vehicles, represented by the speed of other vehicles, is equal to or greater than the first threshold speed V1th. Condition C3: The other vehicle speed Vo is greater than or equal to the "first subtraction value obtained by subtracting the first predetermined value V1pd from the set vehicle speed Vset" and less than or equal to the "second subtraction value obtained by subtracting the second predetermined value V2pd from the set vehicle speed Vset". Note that the first predetermined value V1pd is set to a value greater than the second predetermined value V2pd.

[0085] Step 610: The CPU identifies another vehicle (adjacent vehicle) traveling in front of the current vehicle VA in an adjacent lane as an adjacent lane candidate vehicle if it meets the above candidate vehicle conditions.

[0086] Step 615: The CPU determines whether both a candidate vehicle in its own lane and a candidate vehicle in an adjacent lane exist.

[0087] If both a candidate vehicle in the current lane and a candidate vehicle in an adjacent lane are present, the CPU determines "Yes" in step 615, and the process proceeds to step 620. In step 620, the CPU identifies the vehicle with the larger projected area between the candidate vehicle in the current lane and the candidate vehicle in the adjacent lane as the recommended vehicle to follow. The process then proceeds to step 695, where the CPU terminates this routine. The process then proceeds to step 520 as shown in Figure 5. As a result, only one recommended vehicle image 56 will be displayed (the recommended vehicle image 56 for the preceding vehicle and the recommended vehicle image 56 for the adjacent vehicle will not be displayed simultaneously), thus reducing the possibility of the driver being confused about whether the vehicle to follow behind is the preceding vehicle or the adjacent vehicle.

[0088] If neither the candidate vehicle in the current lane nor any candidate vehicle in the adjacent lane exists, the CPU determines "No" in step 615, and the process proceeds to step 625. In step 625, the CPU determines whether or not a candidate vehicle in the current lane exists.

[0089] If a candidate vehicle exists in the current lane, the CPU determines "Yes" in step 625, and the process proceeds to step 630. In step 630, the CPU identifies the candidate vehicle in the current lane as the recommended vehicle to follow. The process then proceeds to step 695.

[0090] If no candidate vehicles exist in the current lane, the CPU determines "No" in step 625, and the process proceeds to step 635. In step 635, the CPU determines whether or not a candidate vehicle exists in an adjacent lane.

[0091] If there is a candidate vehicle in the adjacent lane, the CPU determines "Yes" in step 635, and the process proceeds to step 640. In step 640, the CPU identifies the candidate vehicle in the adjacent lane as the vehicle recommended to follow. The process then proceeds to step 695.

[0092] If there are no candidate vehicles in the adjacent lane, the CPU determines "No" in step 635, and the process proceeds to step 695. In this case, since there are no recommended vehicles to follow, the recommended follow image 56 is not displayed.

[0093] <Fuel efficiency improvement level identification subroutine> If the process proceeds to step 520 shown in Figure 5, the CPU starts processing from step 700 shown in Figure 7 and executes steps 705 and 710.

[0094] Step 705: The CPU sets the fuel efficiency improvement level to "0". Step 710: The CPU determines whether the vehicle's VA is in the process of suppressing acceleration in the eco-driving support control.

[0095] If the vehicle's VA is in the process of suppressing acceleration, the CPU determines "Yes" in step 710 and executes steps 715 and 720. Step 715: The CPU adds "1" to the fuel efficiency improvement level. Step 720: The CPU determines whether or not there is a preceding vehicle.

[0096] If there is no preceding vehicle, the CPU determines "No" in step 720 and executes steps 725 and 730.

[0097] Step 725: The CPU sets the air resistance reduction effect to "0". Step 730: The CPU adds the effect of reducing air resistance to the fuel efficiency improvement level. The process then proceeds to step 795, where the CPU terminates the routine. The process then proceeds to step 525, as shown in Figure 5.

[0098] If the vehicle's VA is not in suppression acceleration when the process proceeds to step 710, the CPU determines "No" in step 710, and the process proceeds to step 720.

[0099] If a preceding vehicle exists when the process proceeds to step 720, the CPU determines "Yes" in step 720 and executes steps 735 and 740. Step 735: The CPU determines the projected area and the distance D between vehicles. Step 740: The CPU determines the air resistance reduction effect in four stages from "0" to "3" based on the projected area and distance D of the preceding vehicle. The effect of reducing air resistance increases with increasing projected area and with decreasing distance D between vehicles. The process then proceeds to step 730, where the CPU adds the "air resistance reduction effect identified in step 740" to the fuel efficiency improvement level.

[0100] <Alarm routine> When the appropriate time arrives, the CPU starts processing from step 800 in Figure 8, and the processing proceeds to step 805. In step 805, the CPU determines whether the distance D between the preceding vehicle and the current vehicle VA is less than or equal to the warning distance Dal. The warning distance Dal is set to a value smaller than the set distance Dset.

[0101] If the distance between vehicles D is less than or equal to the warning distance Dal, the CPU determines that the collision risk is greater than or equal to the threshold risk. In this case, the CPU determines "Yes" in step 805 and executes steps 810 and 815.

[0102] Step 810: The CPU sets the alarm flag Xal to "1". Step 815: The CPU displays a warning image on the display device 44 to inform the driver of a high risk of collision. The process then proceeds to step 895, and the CPU terminates this routine.

[0103] If the distance between vehicles D is greater than the warning distance Dal, the CPU determines "No" in step 805, and the process proceeds to step 820. In step 820, the CPU determines, based on the forward image data and radar data, whether or not there is a vehicle cutting in front of the vehicle VA.

[0104] If an interrupting vehicle is present, the CPU determines that the collision risk is above the threshold risk. In this case, the CPU determines "Yes" in step 820 and executes steps 810 and 815. As a result, a warning image is displayed on the display device 44.

[0105] If no interrupting vehicle exists, the CPU determines "No" in step 820, and the process proceeds to step 825. In step 825, the CPU sets the alarm flag Xal to "0". After that, the process proceeds to step 895.

[0106] According to this embodiment, the ECU 20 determines that a discouraged condition is met if the collision risk is greater than or equal to the threshold risk, and / or if the driver is performing an accelerator override operation. When a discouraged condition is met, the ECU 20 does not display the fuel efficiency improvement image. This reduces the possibility of follow-up operation being performed in situations where it is not recommended.

[0107] The present invention is not limited to the embodiments described above, and various modifications of the present invention can be adopted.

[0108] <First variation> In the above embodiment, if an adjacent lane candidate vehicle is identified as a recommended vehicle for following (step 535 "Yes") and the vehicle VA is not able to change lanes to the adjacent lane where the recommended vehicle for following is traveling (step 550 "No"), the ECU 20 does not display both the recommended vehicle for following image 56 and the fuel consumption status image 58. However, in this case, the ECU 20 may display only the recommended vehicle for following image 56 and not the fuel consumption status image 58.

[0109] Furthermore, if the vehicle VA is unable to change lanes to the adjacent lane where the recommended following vehicle is traveling, the ECU 20 may, if a candidate vehicle for the vehicle's own lane exists, newly identify that candidate vehicle as the recommended following vehicle and display the recommended following image 56 for that candidate vehicle. This reduces the possibility that the driver may feel uneasy because the recommended following image 56 will suddenly disappear when the vehicle VA is unable to change lanes to the adjacent lane.

[0110] <Second variation> In the above embodiment, in step 530 of the surrounding environment screen display routine shown in Figure 5, the ECU 20 determined that the driver was performing an accelerator override operation if both conditions A1 and A2 were met. However, the ECU 20 may also determine that the driver was performing an accelerator override operation if condition A1 was met.

[0111] <Third variation> In the above embodiment, in the surrounding environment screen display routine shown in Figure 5, the ECU 20 displays the follow recommendation image 56 and the fuel consumption status image 58 as fuel consumption improvement images when a driving assistance request is made and eco-driving assistance control is also requested (step 540). However, the ECU 20 only needs to display the follow recommendation image 56 as a fuel consumption improvement image. Furthermore, the ECU 20 may display the fuel consumption improvement image regardless of whether a driving assistance control request or an eco-driving assistance request control request is made.

[0112] Furthermore, if driving assistance control is not requested, driving assistance control will not be executed. Therefore, regardless of whether the driver is performing an accelerator override operation, the vehicle VA will drive with the requested driving force according to the accelerator operation amount. In this case, if the condition that the accelerator operation amount AP is equal to or greater than the third threshold amount is met, the ECU20 will determine that the unrecommended condition has been met and will not display the fuel efficiency improvement image. The third threshold amount may be the same value as the first threshold amount of condition A1, or it may be a different value.

[0113] <Fourth variation> In the above embodiment, in the fuel efficiency improvement level determination subroutine shown in Figure 7, the ECU 20 added "1" to the fuel efficiency improvement level when the vehicle's VA was undergoing suppressive acceleration (step 710 "Yes"). However, the ECU 20 does not have to add "1" to the fuel efficiency improvement level even when the vehicle's VA is undergoing suppressive acceleration. In other words, the ECU 20 only needs to obtain the fuel efficiency improvement level based at least on the air resistance reduction effect of the preceding vehicle.

[0114] <Fifth variation> In the above embodiment, the warning routine shown in Figure 8 causes the ECU 20 to issue a warning (step 815) if the distance between vehicles D is less than or equal to the warning distance Dal (step 805 "Yes"). However, the ECU 20 may use the TTC of the preceding vehicle instead of the distance between vehicles D. TTC stands for "Time To Collision" and represents the time it takes for an object to collide with the vehicle VA. The ECU 20 obtains the TTC by dividing the distance between vehicles D by the "relative speed Vr of the preceding vehicle with respect to the vehicle VA". If the TTC is less than or equal to the warning time Tal, the ECU 20 determines that the collision risk is greater than or equal to the threshold risk and issues a warning.

[0115] Furthermore, in the above embodiment, the ECU 20 issued an alarm by displaying an alarm image, but it may also issue an alarm by emitting a predetermined alarm sound from a speaker (not shown).

[0116] <Sixth variation> In this modified version of normal constant speed control, the ECU20 performs normal acceleration control when the vehicle speed Vs falls below the lower limit of the vehicle speed range, and performs normal deceleration control when the vehicle speed Vs exceeds the upper limit of the vehicle speed range. The vehicle speed range for eco constant speed control is set to be wider than the vehicle speed range for normal constant speed control.

[0117] In this modified version of the adaptive cruise control, normal acceleration control is performed when the distance D between vehicles exceeds the upper limit of the distance range, and normal deceleration control is performed when the distance D between vehicles falls below the set distance Dset, which is the lower limit of the distance range. The distance range for eco adaptive cruise control is set to be wider than the distance range for normal adaptive cruise control.

[0118] <7th variation> In normal following control and eco following control, the above TTC may be used instead of the distance D between vehicles.

[0119] <8th variation> In the above embodiment, the upper limit Vmax of the vehicle speed range for eco constant speed control is set to the set vehicle speed Vset, but the vehicle speed range only needs to include the set vehicle speed Vset. The lower limit Dmin of the distance range for eco follow control is set to the set distance Dset, but the distance range only needs to include the set distance Dset.

[0120] <9th variation> Eco-deceleration control is not limited to coasting deceleration and regenerative deceleration. Eco-deceleration control is any control that reduces the deceleration rate more than normal deceleration control.

[0121] <10th variation> The device 10 does not need to be equipped with both a forward-facing camera 22 and a millimeter-wave radar 24; it only needs to be equipped with at least one capable of detecting objects.

[0122] The device 10 is applicable to vehicles such as engine-powered vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, and electric vehicles. Furthermore, the device 10 is also applicable to autonomous vehicles. The present invention can also be considered as a non-temporary storage medium in which a program for realizing the functions of the device 10 is stored and which is readable by a computer. [Explanation of Symbols]

[0123] 10...Driving assistance system, 20...ECU, 40...Drive system, 42...Braking system, 44...Display device, 50...Surrounding environment screen, 56...Recommended follow image, 58...Fuel consumption status image.

Claims

1. In a driver assistance device configured to display fuel efficiency improvement images on the vehicle's display device in order to improve the vehicle's fuel efficiency, The aforementioned driving support device, The system displays a recommended follow image as the fuel efficiency improvement image, which recommends that the vehicle follow a recommended follow vehicle that is traveling ahead of the vehicle and whose air resistance reduction effect is greater than or equal to a predetermined value, thereby reducing the air resistance experienced by the vehicle. If the conditions for not recommending following the vehicle mentioned above are met, the recommended following image will not be displayed. A driver assistance system configured in such a way.

2. In the driving support device according to claim 1, The aforementioned driving support device, The discouragement condition is determined to be met if at least one of the following conditions is met: the collision risk, which represents the possibility of the vehicle colliding with an object, is equal to or greater than the threshold risk; and the amount of operation of the vehicle's accelerator control is equal to or greater than the threshold amount. A driver assistance system configured in such a way.

3. In the driving support device according to claim 2, The aforementioned driving support device, The system performs driving support control to either drive the vehicle at a preset speed, or to maintain a preset distance between the vehicle and a preceding vehicle traveling in the same lane as the vehicle, and drive the vehicle. If the second condition is met while the aforementioned driving support control is being executed, the driving support control is interrupted, and the vehicle is driven with the driving force corresponding to the manipulated amount. If the second condition is met, it is determined that the deprecation condition is met. A driver assistance system configured in such a way.

4. In the driving support device according to claim 1, The aforementioned driving support device, In addition to the aforementioned recommended follow image, a fuel efficiency status image representing the current level of fuel efficiency improvement of the vehicle, obtained based on the air resistance reduction effect of a preceding vehicle traveling in front of the vehicle in its own lane, is also displayed as the fuel efficiency improvement image. A driver assistance system configured in such a way.

5. In the driving support device according to claim 1 or claim 4, The aforementioned driving assistance device is configured to acquire the air resistance reduction effect based at least on the projected area of ​​the rear of another vehicle traveling in front of the vehicle itself. Driving assistance system.

6. In the driving support device according to claim 1, The aforementioned driving support device, If an adjacent vehicle traveling ahead of the aforementioned vehicle and in an adjacent lane adjacent to the vehicle's own lane is the vehicle recommended to follow, it is determined whether the aforementioned vehicle can change lanes into the adjacent lane. If the vehicle in question cannot change lanes to the adjacent lane, the recommended following image of the adjacent vehicle will not be displayed. A driver assistance system configured in such a way.

7. In the driving support device according to claim 6, The aforementioned driving support device, If there is a preceding vehicle traveling in the same lane and whose air resistance reduction effect is equal to or greater than the predetermined value, and an adjacent vehicle traveling in the adjacent lane and whose air resistance reduction effect is equal to or greater than the predetermined value, the vehicle with the greater air resistance reduction effect is designated as the recommended vehicle to follow. A driver assistance system configured in such a way.

8. In the driving support device according to claim 7, The aforementioned driving support device, If there is a preceding vehicle traveling in the same lane and whose air resistance reduction effect is equal to or greater than the predetermined value, and an adjacent vehicle traveling in the adjacent lane and whose air resistance reduction effect is equal to or greater than the predetermined value, and the air resistance reduction effect of the adjacent vehicle is greater than that of the preceding vehicle, then it is determined whether the vehicle can change lanes to the adjacent lane. If the vehicle itself cannot change lanes to the adjacent lane, the system identifies a preceding vehicle whose air resistance reduction effect is equal to or greater than the predetermined value as the recommended vehicle to follow, and displays the recommended image of the preceding vehicle. A driver assistance system configured in such a way.

9. In a driving assistance method in which a computer installed in the vehicle displays fuel efficiency improvement images on the vehicle's display device, The aforementioned driving assistance method is The computer displays a follow-recommended image as the fuel efficiency improvement image, which recommends that the vehicle follow a follow-recommended vehicle that is traveling ahead of the vehicle and whose air resistance reduction effect is greater than or equal to a predetermined value, thereby reducing the air resistance experienced by the vehicle. If the computer finds a discouragement condition that is met when it is not recommended to perform driving operations to follow behind the recommended vehicle, the computer does not display the recommended follow image. Driving assistance methods, including those mentioned above.

10. In a program that causes a computer installed in the vehicle to display fuel efficiency improvement images on the vehicle's display device, The program is installed on the computer. The steps include displaying a recommended follow image as the fuel efficiency improvement image, which recommends that the vehicle follow a recommended follow vehicle that is traveling ahead of the vehicle and has an air resistance reduction effect of a predetermined value or more that reduces the air resistance experienced by the vehicle, and If the discouragement condition is met, which is when it is not recommended to perform the driving operation to follow behind the recommended vehicle, the recommended follow image is not displayed. A program that executes something.

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