Vehicle Driving Assistance Device

Abstract

To provide a vehicle driving assistance system that causes a driving device to output drive power with high efficiency and allows an own vehicle to run by follow-up control.SOLUTION: A vehicle driving assistance system 10 performs a follow-up control that allows an own vehicle 100 to run following up a preceding vehicle. In accelerating the own vehicle, the follow-up control is performed in which drive power that can be output with the maximum efficiency is output from a drive device 20 to accelerate the own vehicle. The drive device of the own vehicle is provided with two drive sources 21, 22 with different drive power that can be output at maximum efficiency. A drive device of the preceding vehicle is also provided with two drive sources with different drive power that can be output at maximum efficiency. In a case where the control in which drive power that can be output with the maximum efficiency is output from the drive unit to accelerate the preceding vehicle is performed in the preceding vehicle, and a difference between the drive power that the drive source of the preceding vehicle can output with the maximum efficiency and the drive power that the drive source of the own vehicle can output with the maximum efficiency is a threshold or lower, the vehicle driving assistance system performs the follow-up control.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle driving assistance device. [Background technology]

[0002] Vehicles equipped with an internal combustion engine and a motor as a drive device that outputs a drive force (vehicle drive force) to be applied to the vehicle are known. In such vehicles, an HV mode in which the vehicle drive force is output from both the internal combustion engine and the motor, and an EV mode in which the vehicle drive force is output only from the motor can be selected at will. As such a vehicle, there is known a vehicle that is configured to determine whether to select the HV mode or the EV mode so that the power output efficiency of the drive device when outputting the vehicle drive force is high (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-182629 A Summary of the Invention

[0004] There is known a vehicle driving support device that performs a following control to automatically accelerate and decelerate the host vehicle so that the host vehicle follows a vehicle (a preceding vehicle) traveling ahead of the host vehicle. Even when performing such following control, it is desirable to accelerate the host vehicle so that the power output efficiency of the drive unit is increased.

[0005] Generally, if tracking control is performed so that the vehicle driving force when the power output efficiency is highest is output from the drive unit, the power output efficiency of the drive unit will be maximized. However, when tracking control is performed in this manner, from the perspective of driving in a manner to follow the preceding vehicle, a state in which the acceleration of the host vehicle is excessive or insufficient may arise, and it may be difficult to say that the host vehicle is driving in a manner to follow the preceding vehicle.

[0006] An object of the present invention is to provide a vehicle driving support system that can cause a host vehicle to follow a preceding vehicle through follow-up control even when a drive unit is operated at a high efficiency.

[0007] The vehicle driving assistance device according to the first invention of the present application is a follow-up control that automatically controls the acceleration / deceleration of the host vehicle to make the host vehicle follow a preceding vehicle, and when accelerating the host vehicle, the follow-up control is executed to accelerate the host vehicle by outputting from the host vehicle's drive device the driving force that the drive device of the host vehicle can output with maximum efficiency.

[0008] The drive device of the host vehicle includes at least two power sources each having a different drive force that can be output at maximum efficiency, and the drive device of the preceding vehicle also includes at least two power sources each having a different drive force that can be output at maximum efficiency. The vehicle driving support device according to the first invention of the present application is configured to execute the following control when a maximum efficiency control is executed in the preceding vehicle to accelerate the preceding vehicle by outputting a drive force that can be output at maximum efficiency from the drive device of the preceding vehicle, and a difference between a drive force that can be output at maximum efficiency by one of the power sources of the preceding vehicle and a drive force that can be output at maximum efficiency by one of the power sources of the host vehicle is equal to or less than a predetermined value, and a difference between a drive force that can be output at maximum efficiency by the other of the power sources of the preceding vehicle and a drive force that can be output at maximum efficiency by the other of the power sources of the host vehicle is also equal to or less than the predetermined value. Furthermore, the vehicle driving assistance device according to the first invention of the present application is configured to execute notification control to notify the driver of the host vehicle of the presence of a target vehicle, when the target vehicle is a vehicle around the host vehicle which is equipped with a drive unit having at least two power sources each having different driving forces that can be output with maximum efficiency, and which is executing maximum efficiency control to accelerate the vehicle by outputting from the drive unit of the vehicle a driving force that can be output with maximum efficiency, and in which the difference between the driving force that one of the power sources of the vehicle can output with maximum efficiency and the driving force that one of the power sources of the host vehicle can output with maximum efficiency is less than or equal to the predetermined value, and the difference between the driving force that the other of the power sources of the vehicle can output with maximum efficiency and the driving force that the other of the power sources of the host vehicle can output with maximum efficiency is also less than or equal to the predetermined value.

[0009] According to the present invention, when the following control is performed, when the preceding vehicle accelerates, the drive unit of the host vehicle outputs a drive force that can be output with maximum efficiency (optimum drive force) to accelerate the host vehicle. At this time, the drive unit of the preceding vehicle also outputs a drive force that can be output with maximum efficiency (optimum drive force) to accelerate the preceding vehicle, and this drive force is the same or close to the drive force output by the drive unit of the host vehicle. Therefore, even if the host vehicle is accelerated in this way, the host vehicle will travel following the preceding vehicle. Therefore, even if the drive unit is operated with high efficiency, the following control allows the host vehicle to travel following the preceding vehicle.

[0011] Further, according to the present invention, The driver of the vehicle can know that there is a target vehicle around the vehicle that can be made to follow the preceding vehicle by following control even if the drive device is operated at high efficiency.

[0012] A vehicle driving support device according to a second aspect of the present application is a follow-up control for automatically controlling the acceleration / deceleration of a host vehicle to make the host vehicle follow a preceding vehicle, and when accelerating the host vehicle, executes the follow-up control by causing the drive device of the host vehicle to output a driving force that can be output with maximum efficiency from the drive device of the host vehicle to accelerate the host vehicle. The vehicle driving support device according to the second aspect of the present application is configured to execute the follow-up control when a maximum efficiency control is executed in the preceding vehicle, in which the drive device of the preceding vehicle outputs a driving force that can be output with maximum efficiency from the drive device of the preceding vehicle to accelerate the preceding vehicle, and the difference between the driving force that can be output with maximum efficiency from the drive device of the preceding vehicle and the driving force that can be output with maximum efficiency from the drive device of the preceding vehicle is equal to or less than a predetermined value. Furthermore, the vehicle driving assistance device of the second invention of the present application is configured to execute maximum efficiency control in which a target vehicle is present around the host vehicle and is equipped with a drive unit, and the drive unit of the vehicle is caused to output a drive force that the drive unit of the vehicle can output with maximum efficiency from the drive unit of the vehicle to accelerate the vehicle, and when there is a target vehicle, which is a vehicle in which the difference between the drive force that the drive unit of the vehicle can output with maximum efficiency and the drive force that the drive unit of the vehicle can output with maximum efficiency is equal to or less than the predetermined value, to execute notification control in which the driver of the host vehicle is notified of the presence of the target vehicle.

[0013] According to the present invention, when the following control is performed, when the preceding vehicle accelerates, the drive unit of the host vehicle outputs a drive force that can be output with maximum efficiency (optimum drive force) to accelerate the host vehicle. At this time, the drive unit of the preceding vehicle also outputs a drive force that can be output with maximum efficiency (optimum drive force) to accelerate the preceding vehicle, and this drive force is the same or close to the drive force output by the drive unit of the host vehicle. Therefore, even if the host vehicle is accelerated in this way, the host vehicle will travel following the preceding vehicle. Therefore, even if the drive unit is operated with high efficiency, the following control allows the host vehicle to travel following the preceding vehicle.

[0015] Further, according to the present invention, The driver of the vehicle can know that there is a target vehicle around the vehicle that can be made to follow the preceding vehicle by following control even if the drive device is operated at high efficiency.

[0016] still, The first and second vehicle driving assistance devices of the present application may be configured to perform the following control so as to decelerate the host vehicle by coasting when the preceding vehicle decelerates, when the preceding vehicle is decelerating due to coasting while the maximum efficiency control is being executed on the preceding vehicle.

[0017] According to the present invention, when the following control is executed, if the preceding vehicle decelerates, the host vehicle decelerates by coasting. At this time, the preceding vehicle also decelerates by coasting. Therefore, even if the host vehicle is decelerated in this manner, the host vehicle travels following the preceding vehicle. Furthermore, since the host vehicle is decelerated by coasting, not by friction braking or the like, the energy loss associated with the deceleration of the host vehicle is small. Therefore, the host vehicle can travel following the preceding vehicle with high energy efficiency.

[0018] The components of the present invention are not limited to the embodiments of the present invention described below with reference to the drawings. Other objects, other features and associated advantages of the present invention will be easily understood from the description of the embodiments of the present invention. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram showing a vehicle driving support device according to an embodiment of the present invention and a vehicle (host vehicle) on which the vehicle driving support device is mounted. [Diagram 2] FIG. 2 is a diagram showing the forward inter-vehicle distance and the rear inter-vehicle distance. [Diagram 3] FIG. 3 is a diagram showing vehicles (neighboring vehicles) around the host vehicle. [Figure 4] FIG. 4 is a diagram showing the relationship between the driving force output from the first driving source and the energy efficiency of the first driving source, and the relationship between the driving force output from the second driving source and the energy efficiency of the second driving source. [Diagram 5] FIG. 5 shows a scene where there is neither a preceding vehicle nor a following vehicle. [Figure 6] FIG. 6A is a diagram showing a scene where the forward inter-vehicle distance is longer than the forward mid-distance judgment value, and FIG. 6B is a diagram showing a scene where the forward inter-vehicle distance is equal to or shorter than the forward mid-distance judgment value. [Figure 7] FIG. 7A is a diagram showing a scene where the distance between vehicles ahead is longer than the forward close distance judgment value, and FIG. 7B is a diagram showing a scene where the distance between vehicles ahead is equal to or shorter than the forward close distance judgment value. [Figure 8] FIG. 8A is a diagram showing a situation where the rear inter-vehicle distance is longer than the rear close distance judgment value, and FIG. 8B is a diagram showing a situation where the rear inter-vehicle distance is equal to or smaller than the rear close distance judgment value. [Figure 9] FIG. 9 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. [Figure 10] FIG. 10 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. [Figure 11] FIG. 11 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. [Figure 12]FIG. 12 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. [Figure 13] FIG. 13 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. [Figure 14] FIG. 14 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. [Figure 15] FIG. 15 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. [Figure 16] FIG. 16 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. [Figure 17] FIG. 17 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, a vehicle driving support device according to an embodiment of the present invention will be described with reference to the drawings. A vehicle driving support device 10 according to an embodiment of the present invention is shown in Fig. 1. The vehicle driving support device 10 is mounted on a host vehicle 100.

[0021] <ecu> The vehicle driving assistance device 10 includes an ECU 90. ECU is an abbreviation for electronic control unit. The ECU 90 includes a microcomputer as a main part. The microcomputer includes a CPU, a ROM, a RAM, a non-volatile memory, and an interface. The CPU realizes various functions by executing instructions, programs, or routines stored in the ROM.

[0022] <Drive unit, etc.> The host vehicle 100 is equipped with a drive device 20 and a braking device 30 .

[0023] <Drive unit> The drive device 20 is a device that outputs a drive force (drive torque) given to the host vehicle 100 to make the host vehicle 100 run, and in this example, is composed of two power sources (a first power source 21 and a second power source 22) having different power output characteristics. For example, the first power source 21 and the second power source 22 are an internal combustion engine and a motor, respectively. The first power source 21 and the second power source 22 are each electrically connected to an ECU 90. The ECU 90 can control the drive force (drive torque) output by the first power source 21 and the second power source 22 by controlling the operation of the first power source 21 and the second power source 22, respectively.

[0024] <Brake device> The braking device 30 is a device, such as a brake device, that outputs a braking force applied to the host vehicle 100 in order to brake the host vehicle 100. The braking device 30 is electrically connected to the ECU 90. The ECU 90 can control the braking force (braking torque) output from the braking device 30 by controlling the operation of the braking device 30.

[0025] <Sensors, etc.> Furthermore, the vehicle 100 is equipped with an accelerator pedal 41, an accelerator pedal operation amount sensor 42, a brake pedal 43, a brake pedal operation amount sensor 44, a driving assistance operation device 51, an eco-driving operation device 52, a surrounding information detection device 60, a vehicle speed detection device 70, a transmission / reception device 81, a display 82 and a speaker 83.

[0026] <Accelerator pedal operation amount sensor> Accelerator pedal operation amount sensor 42 is a sensor that detects the amount of operation of accelerator pedal 41, and is electrically connected to ECU 90. Accelerator pedal operation amount sensor 42 transmits information about the detected operation amount to ECU 90. ECU 90 obtains the operation amount of accelerator pedal 41 as accelerator pedal operation amount AP based on the information transmitted from accelerator pedal operation amount sensor 42.

[0027] <Brake pedal operation amount sensor> The brake pedal operation amount sensor 44 is a sensor that detects the amount of operation of the brake pedal 43, and is electrically connected to the ECU 90. The brake pedal operation amount sensor 44 transmits information on the detected operation amount to the ECU 90. The ECU 90 obtains the amount of operation of the brake pedal 43 as a brake pedal operation amount BP based on the information transmitted from the brake pedal operation amount sensor 44.

[0028] <Driving assistance control device> The driving support operation device 51 is a device operated by the driver D of the vehicle 100, and is, for example, a device including switches, buttons, etc. These switches, buttons, etc. are provided, for example, on the steering wheel of the vehicle 100, or on a lever attached to the steering column of the vehicle 100.

[0029] In this example, the driving support operation device 51 includes a driving support selection switch, a vehicle speed setting switch, a vehicle speed increase button, a vehicle speed decrease button, and a vehicle distance setting button. The driving support operation device 51 is electrically connected to the ECU 90.

[0030] When the driver D operates the driving assistance selection switch while driving assistance control, which will be described later, is not being executed, a predetermined signal is transmitted from the driving assistance operation device 51 to the ECU 90. When the ECU 90 receives this signal, it determines that execution of driving assistance control has been requested. On the other hand, when the driver D operates the driving assistance selection switch while driving assistance control is being executed, a predetermined signal is transmitted from the driving assistance operation device 51 to the ECU 90. When the ECU 90 receives this signal, it determines that execution of driving assistance control is no longer being requested. In other words, the ECU 90 determines that termination of driving assistance control has been requested.

[0031] Furthermore, when the driver D operates the vehicle speed setting switch while the driving support control is being executed, a predetermined signal is transmitted from the driving support operation device 51 to the ECU 90. When the ECU 90 receives the signal, it sets the host vehicle speed V1 (the driving speed of the host vehicle 100) at that time as the set vehicle speed Vset for the driving support control.

[0032] Furthermore, when the driver D operates the vehicle speed increase button while driving support control is being executed, a predetermined signal is transmitted from the driving support operation device 51 to the ECU 90. When the ECU 90 receives this signal, it increases the set vehicle speed Vset. On the other hand, when the driver D operates the vehicle speed decrease button while driving support control is being executed, a predetermined signal is transmitted from the driving support operation device 51 to the ECU 90. When the ECU 90 receives this signal, it decreases the set vehicle speed Vset.

[0033] Furthermore, when the driver D operates the following distance setting button while driving support control is being executed, a predetermined signal is transmitted from the driving support operation device 51 to the ECU 90. This signal is a signal (requested following distance signal) that indicates the distance (requested following distance DFreq) that the driver D requests as the distance (forward following distance DF) between the host vehicle 100 and the preceding vehicle 200F in the following driving control of the driving support control by operating the following distance setting button.

[0034] 2, the forward inter-vehicle distance DF is the distance between the host vehicle 100 and the preceding vehicle 200F, and is acquired based on the periphery detection information IS described later. In this example, the preceding vehicle 200F is a vehicle traveling ahead of the host vehicle 100 in the host lane LN (the lane in which the host vehicle 100 is traveling), and has a forward inter-vehicle distance DF that is equal to or less than a predetermined distance (preceding vehicle determination distance DFth). The host lane LN is recognized based on information related to the left-side marking line LML and the right-side marking line LMR of the host vehicle 100, which are acquired based on the periphery detection information IS described later. In this example, the requested forward inter-vehicle distance DFreq that the driver D can select by operating the inter-vehicle distance setting button is one of three types: a long distance, a medium distance, and a short distance.

[0035] When the ECU 90 receives a required vehicle distance signal, it may set the required vehicle distance DFreq as the set vehicle distance DFset without taking into account the vehicle speed V1 at that time, but in this example, it sets the set vehicle distance DFset based on the vehicle speed V1 and the required vehicle distance DFreq at that time.

[0036] Specifically, the ECU 90 sets the front inter-vehicle distance DF, which is a predetermined time (predetermined predicted arrival time TTCref) obtained by dividing the time (predetermined predicted arrival time TTC) by the vehicle speed V1 at that time, as the set front inter-vehicle distance DFset. That is, the ECU 90 sets the front inter-vehicle distance DF, which is a relationship between the vehicle speed V1 at that time, the predetermined predicted arrival time TTCref, and the front inter-vehicle distance DF, as the set front inter-vehicle distance DFset, which is expressed by the following formula 1.

[0037] TTCref=DF / V1 …(1)

[0038] The specified predicted arrival time TTCref is a longer time TTClong when the required headway distance DFreq is a longer distance, a medium time TTCmid when the required headway distance DFreq is a medium distance, and a shorter time TTCshort when the required headway distance DFreq is a shorter distance.

[0039] The preceding vehicle determination distance DFth is determined to be longer than the set front inter-vehicle distance DFset.

[0040] <Eco driving control device> The eco-driving operation device 52 is a device operated by the driver D of the vehicle 100, and is, for example, a device including switches, buttons, etc. These switches, buttons, etc. are provided, for example, on the steering wheel of the vehicle 100, or on a lever attached to the steering column of the vehicle 100.

[0041] When the eco-driving operation device 52 is operated while it is in the OFF position, it is set to the ON position. When the eco-driving operation device 52 is operated to the ON position, it transmits a predetermined signal to the ECU 90. When the ECU 90 receives the signal, it determines that the execution of eco-driving support control, which will be described later, has been requested.

[0042] On the other hand, when the eco-driving operation device 52 is operated while it is in the ON position, it is set to the OFF position. When the eco-driving operation device 52 is operated to the OFF position, it transmits a predetermined signal to the ECU 90. When the ECU 90 receives the signal, it determines that the execution of eco-driving support control is no longer required.

[0043] <Peripheral information detection device> The surrounding information detection device 60 is a device that detects information about the surroundings of the vehicle 100, and in this example, includes a radio wave sensor 61 and an image sensor 62. The radio wave sensor 61 is, for example, a radar sensor (such as a millimeter wave radar). The image sensor 62 is, for example, a camera. The surrounding information detection device 60 may also include a sonic sensor such as an ultrasonic sensor (clearance sonar) or an optical sensor such as a laser radar (LiDAR).

[0044] <Radio wave sensor> The radio wave sensor 61 is a sensor that transmits radio waves and receives radio waves reflected by objects (reflected waves), and is electrically connected to the ECU 90. The radio wave sensor 61 transmits information related to the transmitted radio waves and received radio waves (reflected waves) to the ECU 90. In other words, the radio wave sensor 61 detects objects (e.g., vehicles) present in the vicinity of the vehicle 100, and transmits information (detection results) related to the detected objects to the ECU 90. The ECU 90 can acquire information (periphery detection information IS) related to objects present in the vicinity of the vehicle 100 based on the information (radio wave information).

[0045] <Image sensor> The image sensor 62 is a sensor that captures an image of the surroundings of the vehicle 100, and is electrically connected to the ECU 90. The image sensor 62 transmits information related to the captured image to the ECU 90. The ECU 90 can obtain information (surroundings detection information IS) related to the surroundings of the vehicle 100 based on the information (image information).

[0046] <Vehicle speed detection device> The vehicle speed detection device 70 is a device that detects the traveling speed (host vehicle speed V1) of the host vehicle 100, and is, for example, a wheel speed sensor. The vehicle speed detection device 70 is electrically connected to the ECU 90. The vehicle speed detection device 70 transmits information related to the detected host vehicle speed V1 to the ECU 90. The ECU 90 acquires the host vehicle speed V1 based on the information.

[0047] <Transmitter / receiver> The transmission / reception device 81 is a device that receives wireless signals transmitted from vehicles (nearby vehicles 200S) present around the vehicle 100 as shown in Fig. 3, and transmits wireless signals from the vehicle 100 to the outside, and is electrically connected to the ECU 90. The ECU 90 can acquire wireless signals transmitted from the nearby vehicles 200S via the transmission / reception device 81, and can transmit wireless signals from the vehicle 100 to the outside via the transmission / reception device 81. The ECU 90 acquires information related to the nearby vehicles 200S (vehicle-to-vehicle communication information IV) based on the wireless signals transmitted from the nearby vehicles 200S.

[0048] <Display> The display 82 is a device that displays various images, and is electrically connected to the ECU 90. The ECU 90 can display various images on the display 82.

[0049] <Speaker> The speaker 83 is a device that outputs various sounds, and is electrically connected to the ECU 90. The ECU 90 can output various sounds from the speaker 83.

[0050] <Overview of operation of vehicle driving assistance device> Next, an outline of the operation of the vehicle driving support device 10 will be described. The vehicle driving support device 10 is configured to be capable of executing driving support control for automatically controlling the acceleration / deceleration of the host vehicle 100 so that a predetermined condition is satisfied, regardless of the operation of the accelerator pedal 41 and the brake pedal 43 by the driver D.

[0051] As described above, the drive device 20 is composed of the first power source 21 and the second power source 22, and the first power source 21 and the second power source 22 have different power output characteristics. In this example, the first power source 21 and the second power source 22 have the power output characteristics shown in Fig. 4. That is, the energy efficiency (energy efficiency E1 of the first power source 21) when the first power source 21 (e.g., an internal combustion engine) outputs a driving force is highest when the driving force (first driving force PD1) output by the first power source 21 is a certain value PDa, and the energy efficiency (energy efficiency E2 of the second power source 22) when the second power source 22 (e.g., a motor) outputs a driving force is highest when the driving force (second driving force PD2) output by the second power source 22 is a value PDb smaller than the above value PDa.

[0052] When the first power source 21 is an internal combustion engine, the energy efficiency E1 of the first power source 21 is what is called fuel efficiency, and when the second power source 22 is a motor, the energy efficiency E2 of the second power source 22 is what is called electricity efficiency.

[0053] In this way, the energy efficiency when the drive unit 20 outputs a driving force (the energy efficiency E of the drive unit 20) has a characteristic of peaking (being highest) when the driving force PD output by the drive unit 20 is a specific value (optimum driving force PDopt), and there are multiple peaks (two in this example). Therefore, if the optimum driving force PDopt is output from the drive unit 20 to accelerate the host vehicle 100, the energy efficiency E of the drive unit 20 will be high.

[0054] Therefore, when executing driving support control, the vehicle driving support device 10 executes driving support control as follows depending on the presence or absence of the preceding vehicle 200F and the following vehicle 200R.

[0055] As described above, in this example, the preceding vehicle 200F is a vehicle traveling in front of the host vehicle 100 on the host lane LN, and has a forward inter-vehicle distance DF that is equal to or less than the preceding vehicle determination distance DFth. The forward inter-vehicle distance DF is acquired based on the surrounding detection information IS. Also, in this example, the following vehicle 200R is a vehicle traveling behind the host vehicle 100 on the host lane LN, and has a distance (rear inter-vehicle distance DR) from the host vehicle 100 that is equal to or less than a predetermined distance (following vehicle determination distance DRth), as shown in FIG. The rear inter-vehicle distance DR is also acquired based on the surrounding detection information IS.

[0056] When the vehicle driving assistance device 10 determines that the execution of driving assistance control has been requested, it may determine that the driving assistance request condition Cass_req is satisfied regardless of whether the accelerator pedal 41 or the brake pedal 43 is operated. In this example, however, when it determines that the execution of driving assistance control has been requested and neither the accelerator pedal 41 nor the brake pedal 43 is operated, it determines that the driving assistance request condition Cass_req is satisfied.

[0057] When the vehicle driving support device 10 determines that the execution of the driving support control is no longer required, the vehicle driving support device 10 determines that the driving support request condition Cass_req is no longer satisfied. Furthermore, the vehicle driving support device 10 also determines that the driving support request condition Cass_req is no longer satisfied when the accelerator pedal 41 or the brake pedal 43 is operated while the driving support control is being executed.

[0058] <Normal driving support control> If the driving assistance request condition Cass_req is satisfied but the eco-driving request condition Ceco_req is not satisfied, the vehicle driving assistance device 10 determines that the normal driving assistance condition Cn is satisfied, and executes normal following control or normal constant speed control depending on whether or not a preceding vehicle 200F is present.

[0059] In addition, when the vehicle driving assistance device 10 determines that the execution of eco-driving assistance control has been requested, it determines that the eco-driving request condition Ceco_req is satisfied, and when it determines that the execution of eco-driving assistance control is no longer requested, it determines that the eco-driving request condition Ceco_req is no longer satisfied.

[0060] When it is determined that the normal driving support condition Cn is satisfied, the vehicle driving support device 10 determines whether or not the preceding vehicle 200F exists. When the preceding vehicle 200F exists, the vehicle driving support device 10 executes normal following control. On the other hand, when the preceding vehicle 200F does not exist, the vehicle driving support device 10 executes normal constant speed control.

[0061] <Normal tracking control> When the vehicle driving support device 10 starts the normal following control, it accelerates or decelerates the host vehicle 100 so that the forward inter-vehicle distance DF is maintained at the set forward inter-vehicle distance DFset. In this example, when the vehicle driving support device 10 starts the normal following control, it accelerates or decelerates the host vehicle 100 so that the predicted arrival time TTC is maintained at a predetermined predicted arrival time TTCref.

[0062] More specifically, during execution of normal tracking control, the vehicle driving assistance device 10 calculates the acceleration G of the host vehicle 100 required to control the predicted arrival time TTC to a predetermined predicted arrival time TTCref as the required acceleration Greq. At this time, the vehicle driving assistance device 10 calculates the required acceleration Greq so that the speed at which the predicted arrival time TTC converges to the predetermined predicted arrival time TTCref (convergence speed) is equal to or greater than a predetermined speed.

[0063] When the vehicle driving assistance device 10 calculates the required acceleration Greq, it calculates a required driving force PDreq or a required braking force PBreq to achieve the required acceleration Greq, and controls the operation of the driving device 20 and / or the braking device 30 so that the required driving force PDreq or the required braking force PBreq is output. According to this, the vehicle driving assistance device 10 accelerates the host vehicle 100 when the predicted arrival time TTC exceeds a predetermined predicted arrival time TTCref, and decelerates the host vehicle 100 when the predicted arrival time TTC falls below the predetermined predicted arrival time TTCref.

[0064] <Normal constant speed control> On the other hand, when the vehicle driving assistance device 10 starts the normal constant speed control, it accelerates or decelerates the host vehicle 100 so that the host vehicle speed V1 is maintained at the set vehicle speed Vset. In this example, while the normal constant speed control is being executed, the vehicle driving assistance device 10 calculates the acceleration G of the host vehicle 100 required to control the host vehicle speed V1 to the set vehicle speed Vset as the required acceleration Greq. At this time, the vehicle driving assistance device 10 calculates the required acceleration Greq so that the speed at which the host vehicle speed V1 converges to the set vehicle speed Vset (convergence speed) is equal to or higher than a predetermined speed.

[0065] When the vehicle driving assistance device 10 calculates the required acceleration Greq, it calculates a required driving force PDreq or a required braking force PBreq to achieve the required acceleration Greq, and accelerates or decelerates the host vehicle 100 by controlling the operation of the driving device 20 and / or the braking device 30 so that the required driving force PDreq or the required braking force PBreq is output. According to this, the vehicle driving assistance device 10 accelerates the host vehicle 100 when the host vehicle speed V1 falls below the set vehicle speed Vset, and decelerates the host vehicle 100 when the host vehicle speed V1 exceeds the set vehicle speed Vset.

[0066] Although the vehicle driving assistance device 10 accelerates or decelerates the host vehicle 100 based on the set vehicle speed Vset when performing normal constant speed control, for example, as a criterion for determining whether to accelerate or decelerate the host vehicle 100, a vehicle speed range (first vehicle speed range R1) including the set vehicle speed Vset may be determined according to the set vehicle speed Vset, and when the host vehicle speed V1 falls below a lower limit value Vlow1 of the first vehicle speed range R1, the host vehicle 100 is accelerated, and when the host vehicle speed V1 exceeds an upper limit value Vup1 of the first vehicle speed range R1, the host vehicle 100 is decelerated. According to this, the average vehicle speed Vave (average value of the host vehicle speed V1) of the host vehicle 100 is controlled to be close to the set vehicle speed Vset.

[0067] <Eco-driving support control> On the other hand, if the eco-driving request condition Ceco_req is satisfied when the driving support request condition Cass_req is satisfied, the vehicle driving support device 10 determines that the eco-driving support condition Ceco is satisfied. If the vehicle driving support device 10 determines that the eco-driving support condition Ceco is satisfied, the vehicle driving support device 10 determines whether or not an eco-following target vehicle 200E exists.

[0068] The eco-following target vehicle 200E is at least a vehicle (peripheral vehicle 200S) surrounding the host vehicle 100, which is executing control (maximum efficiency control) to accelerate the peripheral vehicle 200S by outputting the driving force that can be output with maximum efficiency from the driving device of the peripheral vehicle 200S, and where the difference between the driving force that can be output with maximum efficiency by the driving device of the peripheral vehicle 200S (optimum driving force of the peripheral vehicle 200S) and the driving force that can be output with maximum efficiency by the driving device 20 of the host vehicle 100 (optimum driving force PDopt of the host vehicle 100) is less than a predetermined value.

[0069] In this example, the eco-following target vehicle 200E is a vehicle (surrounding vehicle 200S) around the host vehicle 100, which is executing at least one of the eco-driving support controls described below, and whose drive unit has power output characteristics that are the same as or similar to the power output characteristics of the drive unit 20 of the host vehicle 100.

[0070] Moreover, the predetermined value is set to a value small enough that the power output characteristics of the drive unit of the surrounding vehicle 200S can be regarded as being the same as the power output characteristics of the drive unit 20 of the host vehicle 100.

[0071] In this example, since information related to the control being executed on the drive unit of the surrounding vehicle 200S is included in the inter-vehicle communication information IV, the vehicle driving assistance device 10 determines whether or not maximum efficiency control (control for accelerating the surrounding vehicle 200S by outputting the optimal drive force for the surrounding vehicle 200S from the drive unit of the surrounding vehicle 200S) is being executed in the surrounding vehicle 200S based on the inter-vehicle communication information IV (in this example, whether or not at least one of the eco-driving assistance controls described below is being executed in the surrounding vehicle 200S).

[0072] Furthermore, in this example, since information relating to the power output characteristics of the drive unit of the nearby vehicle 200S is included in the vehicle-to-vehicle communication information IV, the vehicle driving assistance device 10 determines, based on the vehicle-to-vehicle communication information IV, whether or not the difference between the optimal drive force of the nearby vehicle 200S and the optimal drive force of the host vehicle 100 is less than a predetermined value (in this example, whether or not the drive unit of the nearby vehicle 200S has power output characteristics that are the same as or similar to the power output characteristics of the drive unit 20 of the host vehicle 100).

[0073] Note that information related to the control being executed on the drive device of the nearby vehicle 200S may not be included in the inter-vehicle communication information IV. In this case, the vehicle driving support device 10 acquires the drive force output from the drive device of the nearby vehicle 200S (the drive force of the nearby vehicle 200S) based on the surrounding detection information IS, and determines whether or not the maximum efficiency control is being executed in the nearby vehicle 200S based on the acquired drive force (in this example, whether or not at least one of the eco-driving support controls described below is being executed in the nearby vehicle 200S).

[0074] More specifically, the vehicle driving assistance device 10 acquires the peak value of the acceleration of the surrounding vehicle 200S (peak acceleration of the surrounding vehicle 200S) based on the surrounding detection information IS, and if the acquired peak acceleration is consolidated into two specific values, it determines that maximum efficiency control is being executed in the surrounding vehicle 200S (in this example, at least one of the eco-driving assistance controls described below is being executed in the surrounding vehicle 200S).

[0075] Also, information related to the power output characteristics of the drive unit of the nearby vehicle 200S may not be included in the inter-vehicle communication information IV. In this case, the vehicle driving assistance device 10 acquires the drive force of the nearby vehicle 200S based on the surrounding detection information IS, and determines whether or not the difference between the optimal drive force of the nearby vehicle 200S and the optimal drive force of the host vehicle 100 is equal to or less than a predetermined value based on the acquired drive force (in this example, whether or not the drive unit of the nearby vehicle 200S has the same or similar power output characteristics as the drive unit 20 of the host vehicle 100).

[0076] More specifically, the vehicle driving assistance device 10 acquires the peak acceleration of the surrounding vehicle 200S based on the surrounding detection information IS, and if the difference between the acquired peak acceleration and the peak value of the acceleration of the host vehicle 100 caused by the drive unit 20 (peak acceleration of the host vehicle 100) is less than a predetermined value, it determines that the difference between the optimal driving force of the surrounding vehicle 200S and the optimal driving force of the host vehicle 100 is less than a predetermined value.

[0077] In this example, the vehicle driving assistance device 10 acquires the peak acceleration of the surrounding vehicle 200S based on the surrounding detection information IS, and if the difference between the acquired peak acceleration and the peak acceleration of the host vehicle 100 is zero, it determines that the drive unit of the surrounding vehicle 200S has the same power output characteristics as the power output characteristics of the drive unit 20 of the host vehicle 100, and if the difference between the peak acceleration of the surrounding vehicle 200S and the peak acceleration of the host vehicle 100 is greater than zero but less than a predetermined value, it determines that the drive unit of the surrounding vehicle 200S has power output characteristics similar to the power output characteristics of the drive unit 20 of the host vehicle 100.

[0078] When an eco-following target vehicle 200E is present, the vehicle driving assistance device 10 determines whether the eco-following target vehicle 200E is the preceding vehicle 200F based on the inter-vehicle communication information IV and / or the surrounding detection information IS.

[0079] When the eco-following target vehicle 200E is the preceding vehicle 200F, the vehicle driving assistance device 10 determines whether or not the minimum forward inter-vehicle distance DFmin can be secured when the following vehicle 200R is not present, and determines whether or not the minimum forward inter-vehicle distance DFmin and the minimum rear inter-vehicle distance DRmin can be secured when the following vehicle 200R is present.

[0080] The minimum forward inter-vehicle distance DFmin is the minimum forward inter-vehicle distance DF required to avoid the host vehicle 100 from colliding with the preceding vehicle 200F when the eco-following control described later is executed, and the minimum rear inter-vehicle distance DRmin is the minimum rear inter-vehicle distance DR required to avoid the host vehicle 100 from colliding with the following vehicle 200R when the eco-following control described later is executed.

[0081] The vehicle driving assistance device 10 executes eco-following control as eco-driving assistance control when the minimum forward inter-vehicle distance DFmin can be secured when the following vehicle 200R is not present, or when the minimum forward inter-vehicle distance DFmin and the minimum rear inter-vehicle distance DRmin can be secured when the following vehicle 200R is present.

[0082] When the vehicle driving support device 10 starts the eco-following control, it judges whether or not the adjustment of the front inter-vehicle distance DF and / or the rear inter-vehicle distance DR (adjustment of the inter-vehicle distance) is necessary. In this example, when the front inter-vehicle distance DF is shorter than the minimum front inter-vehicle distance DFmin and when the rear inter-vehicle distance DR is shorter than the minimum rear inter-vehicle distance DRmin, the vehicle driving support device 10 judges that the adjustment of the inter-vehicle distance is necessary.

[0083] When the vehicle driving assistance device 10 determines that an adjustment of the inter-vehicle distance is necessary, if the forward inter-vehicle distance DF is shorter than the minimum forward inter-vehicle distance DFmin, the vehicle driving assistance device 10 performs an inter-vehicle distance adjustment to lengthen the forward inter-vehicle distance DF to the minimum forward inter-vehicle distance DFmin by decelerating the vehicle 100, and if the rear inter-vehicle distance DR is shorter than the minimum rear inter-vehicle distance DRmin, the vehicle driving assistance device 10 performs an inter-vehicle distance adjustment to lengthen the rear inter-vehicle distance DR to the minimum rear inter-vehicle distance DRmin by accelerating the vehicle 100.

[0084] When it becomes unnecessary to adjust the distance between the vehicles, the vehicle driving assistance device 10 determines whether the eco-tracking target vehicle 200E has accelerated and whether the eco-tracking target vehicle 200E has decelerated.

[0085] In this example, since information regarding the acceleration or deceleration of the eco-following target vehicle 200E is included in the inter-vehicle communication information IV, the vehicle driving assistance device 10 determines whether the eco-following target vehicle 200E has accelerated and whether the eco-following target vehicle 200E has decelerated based on the inter-vehicle communication information IV.

[0086] In addition, information related to the acceleration or deceleration of the eco-following target vehicle 200E may not be included in the inter-vehicle communication information IV. In this case, the vehicle driving assistance device 10 determines whether the eco-following target vehicle 200E has accelerated and whether the eco-following target vehicle 200E has decelerated based on the surrounding detection information IS.

[0087] When the eco-following target vehicle 200E accelerates, the vehicle driving assistance device 10 executes optimal acceleration control to accelerate the host vehicle 100. In this example, the optimal acceleration control is a control that calculates, as a required acceleration Greq, an acceleration (optimum acceleration Gopt) of the host vehicle 100 at which the energy efficiency E of the drive device 20 is maximized when the drive device 20 outputs a drive force PD taking into account the host vehicle speed V1 at that time, calculates a required drive force PDreq for achieving the required acceleration Greq, and controls the operation of the drive device 20 so that the required drive force PDreq is output.

[0088] On the other hand, when the eco-following target vehicle 200E decelerates, the vehicle driving assistance device 10 executes coasting deceleration control to decelerate the host vehicle 100. In this example, the coasting deceleration control is control for controlling the operation of the drive device 20 so that the driving force PD output from the drive device 20 becomes zero. In other words, the coasting deceleration control is control for coasting the host vehicle 100.

[0089] Furthermore, when the second power source 22 is a motor, the vehicle driving assistance device 10 may be configured to decelerate the host vehicle 100 by coasting deceleration control, by rotating the motor using the running energy of the host vehicle 100 to regenerate electricity, thereby decelerating the host vehicle 100.

[0090] Moreover, when the eco-tracking target vehicle 200E is neither accelerating nor decelerating, the vehicle driving assistance device 10 executes steady driving control. The steady driving control is a control for calculating a required driving force PDreq or a required braking force PBreq for maintaining the vehicle speed V1 at that time, and controlling the operation of the driving device 20 and / or the braking device 30 so that the required driving force PDreq or the required braking force PBreq is output.

[0091] Furthermore, when it is not possible to ensure the minimum front inter-vehicle distance DFmin or when it is not possible to ensure the minimum rear inter-vehicle distance DRmin, the vehicle driving assistance device 10 executes the normal following control described above.

[0092] Furthermore, when an eco-following target vehicle 200E is present but the eco-following target vehicle 200E is not the preceding vehicle 200F, the vehicle driving assistance device 10 determines that the eco-following condition Cacc_eco is not satisfied and executes notification control to inform the driver D of the presence of the eco-following target vehicle 200E. The notification control is, for example, control to display an image indicating the presence of the eco-following target vehicle 200E on the display 82 and / or control to output a sound indicating the presence of the eco-following target vehicle 200E from the speaker 83.

[0093] Furthermore, the vehicle driving assistance device 10 may be configured to automatically move the driving position of the host vehicle 100 so that the host vehicle 100 drives behind the eco-following target vehicle 200E when an eco-following target vehicle 200E exists but the eco-following target vehicle 200E is not the preceding vehicle 200F.

[0094] After starting the notification control, the vehicle driving assistance device 10 determines whether or not the preceding vehicle 200F or the following vehicle 200R is present.

[0095] Moreover, when it is determined that the eco-following target vehicle 200E does not exist, the vehicle driving assistance device 10 determines that the eco-following condition Cacc_eco is not satisfied, and determines whether or not the preceding vehicle 200F or the following vehicle 200R exists. In this case, the notification control is not executed.

[0096] <When there is no vehicle ahead and no vehicle following> When the eco-following condition Cacc_eco is not satisfied, and there is neither the preceding vehicle 200F nor the following vehicle 200R as shown in FIG. 5, the vehicle driving assistance device 10 executes the first eco-driving assistance control (eco constant speed control) described below as the eco-driving assistance control.

[0097] That is, when the vehicle driving support device 10 starts the first eco-driving support control, it sets the range of the host vehicle speed V1 (second vehicle speed range R2) used to determine whether to accelerate or decelerate the host vehicle 100 according to the set vehicle speed Vset. In this example, the second vehicle speed range R2 is a range that includes the set vehicle speed Vset and is set to a range wider than the first vehicle speed range R1. In addition, when the set vehicle speed Vset is the same value, the upper limit value Vup2 of the second vehicle speed range R2 is set to a value larger than the upper limit value Vup1 of the first vehicle speed range R1, and the lower limit value Vlow2 of the second vehicle speed range R2 is set to a value smaller than the lower limit value Vlow1 of the first vehicle speed range R1.

[0098] When the second vehicle speed range R2 is set, the vehicle driving support device 10 executes optimal acceleration control when the host vehicle speed V1 falls below a lower limit value Vlow2 of the second vehicle speed range R2, and executes coasting deceleration control when the host vehicle speed V1 exceeds an upper limit value Vup2 of the second vehicle speed range R2. This controls the average vehicle speed Vave of the host vehicle 100 (average value of the host vehicle speed V1) to be close to the set vehicle speed Vset.

[0099] <When there is a vehicle ahead and no vehicle following> On the other hand, when the eco-following condition Cacc_eco is not satisfied, and there is a preceding vehicle 200F but no following vehicle 200R as shown in Fig. 6, the vehicle driving support device 10 judges whether the host vehicle 100 is traveling at a distance of a medium distance or more from the preceding vehicle 200F (whether the forward medium distance condition CFm is not satisfied). In this example, as this judgment, the vehicle driving support device 10 judges whether the forward inter-vehicle distance DF is longer than a predetermined distance (forward medium distance judgment value DFm). The forward medium distance judgment value DFm is set to a distance shorter than the preceding vehicle judgment distance DFth.

[0100] As shown in (A) of Figure 6, when the forward inter-vehicle distance DF is longer than the forward medium distance judgment value DFm, the vehicle driving assistance device 10 determines that the forward medium distance condition CFm is not satisfied, and executes the second eco-driving assistance control as the eco-driving assistance control.

[0101] When the second eco-driving support control is started, the vehicle driving support device 10 determines whether the host vehicle 100 is approaching the preceding vehicle 200F at a relatively high speed (whether the second deceleration condition CD2 is satisfied). In this example, to make this determination, the vehicle driving support device 10 determines whether the host vehicle speed V1 is faster than the vehicle speed VF of the preceding vehicle 200F and the difference ΔVF between these vehicle speeds is greater than a predetermined value (forward approaching vehicle speed difference ΔVFa).

[0102] When the second deceleration condition CD2 is satisfied, the vehicle driving assistance device 10 executes the coasting deceleration control.

[0103] On the other hand, when the second deceleration condition CD2 is not satisfied, the vehicle driving assistance device 10 judges whether the host vehicle speed V1 is very slow and the host vehicle 100 is being separated from the preceding vehicle 200F at a relatively fast speed (whether the second acceleration condition CA2 is satisfied). In this example, as this judgment, the vehicle driving assistance device 10 judges whether the host vehicle speed V1 is lower than the lower limit value Vlow2 of the second vehicle speed range R2, the host vehicle speed V1 is slower than the vehicle speed VF of the preceding vehicle 200F, and the difference ΔVF between these vehicle speeds is larger than a predetermined value (forward separation vehicle speed difference ΔVFb). The forward separation vehicle speed difference ΔVFb may be the same value as the forward approaching vehicle speed difference ΔVFa, or may be a different value.

[0104] When the second acceleration condition CA2 is satisfied, the vehicle driving support device 10 executes the optimal acceleration control. On the other hand, when it is determined that the second acceleration condition CA2 is not satisfied, the vehicle driving support device 10 executes the steady running control.

[0105] On the other hand, when the forward inter-vehicle distance DF is equal to or less than the forward medium distance judgment value DFm as shown in (B) of FIG. 6, the vehicle driving support device 10 judges that the forward medium distance condition CFm is satisfied. When the vehicle driving support device 10 judges that the forward medium distance condition CFm is satisfied, the vehicle driving support device 10 judges whether the host vehicle 100 is not traveling very close to the preceding vehicle 200F (whether the second coasting allowance condition CDP2 is satisfied). In this example, as this judgment, the vehicle driving support device 10 judges whether the forward inter-vehicle distance DF is longer than a predetermined distance (forward close distance judgment value DFs). The forward close distance judgment value DFs is set to a distance shorter than the forward medium distance judgment value DFm.

[0106] As shown in Fig. 7A, when the forward inter-vehicle distance DF is longer than the forward close distance judgment value DFs, the vehicle driving support device 10 determines that the second coasting allowance condition CDP2 is satisfied and executes coasting deceleration control. On the other hand, as shown in Fig. 7B, when the forward inter-vehicle distance DF is equal to or less than the forward close distance judgment value DFs, the vehicle driving support device 10 determines that the second coasting allowance condition CDP2 is not satisfied and executes normal driving support control. At this time, since the preceding vehicle 200F exists, the vehicle driving support device 10 executes normal following control as normal driving support control.

[0107] <When there is no vehicle ahead and a vehicle following> Furthermore, when the eco-following condition Cacc_eco is not satisfied, and there is no preceding vehicle 200F as shown in Fig. 8 but there is a following vehicle 200R, the vehicle driving support device 10 judges whether the host vehicle 100 is traveling very close to the following vehicle 200R (whether the rear close distance condition CRs is not satisfied). In this example, as this judgment, the vehicle driving support device 10 judges whether the rear inter-vehicle distance DR is longer than a predetermined distance (rear close distance judgment value DRs). The rear close distance judgment value DRs is set to a distance shorter than the following vehicle judgment distance DRth.

[0108] As shown in (A) of Figure 8, when the rear inter-vehicle distance DR is longer than the rear close distance judgment value DRs, the vehicle driving assistance device 10 determines that the rear close distance condition CRs is not satisfied and executes the third eco-driving assistance control as the eco-driving assistance control.

[0109] When the vehicle driving assistance device 10 starts the third eco-driving assistance control, it determines whether the following vehicle 200R is approaching the host vehicle 100 at a relatively high speed and whether an increase in the host vehicle speed V1 is permitted (whether the third acceleration condition CA3 is established). In this example, to make this determination, the vehicle driving assistance device 10 determines whether the host vehicle speed V1 is slower than the vehicle speed VR of the following vehicle 200R, the difference ΔVR between the vehicle speeds is greater than a predetermined value (rear approaching vehicle speed difference ΔVRa), and the host vehicle speed V1 is lower than the upper limit value Vup2 of the second vehicle speed range R2.

[0110] When the third acceleration condition CA3 is satisfied, the vehicle driving assistance device 10 executes the optimal acceleration control. On the other hand, when the third acceleration condition CA3 is not satisfied, the vehicle driving assistance device 10 executes the steady running control.

[0111] On the other hand, when the rear inter-vehicle distance DR is equal to or less than the rear close distance judgment value DRs as shown in (B) of Fig. 8, the vehicle driving support device 10 determines that the rear close distance condition CRs is satisfied. When the vehicle driving support device 10 determines that the rear close distance condition CRs is satisfied, the vehicle driving support device 10 determines whether or not an increase in the host vehicle speed V1 is permitted (whether or not the third acceleration allowable condition CAP3 is satisfied). In this example, as this determination, the vehicle driving support device 10 determines whether or not the host vehicle speed V1 is slower than the upper limit value Vup2 of the second vehicle speed range R2.

[0112] When the host vehicle speed V1 is slower than the upper limit value Vup2 of the second vehicle speed range R2, the vehicle driving support device 10 determines that the third acceleration allowable condition CAP3 is satisfied, and executes optimal acceleration control. On the other hand, when the host vehicle speed V1 is equal to or greater than the upper limit value Vup2 of the second vehicle speed range R2, the vehicle driving support device 10 determines that the third acceleration allowable condition CAP3 is not satisfied, and executes normal driving support control. At this time, since the preceding vehicle 200F does not exist, the vehicle driving support device 10 executes normal constant speed control as normal driving support control.

[0113] <When there is a vehicle ahead and a vehicle behind> Moreover, when the eco-following condition Cacc_eco is not satisfied, the vehicle driving support device 10 executes normal driving support control when the preceding vehicle 200F and the following vehicle 200R are present as shown in Fig. 2. At this time, since the preceding vehicle 200F is present, the vehicle driving support device 10 executes normal following control as normal driving support control.

[0114] <Effects> According to the vehicle driving support device 10, when the eco-following control is executed, when the preceding vehicle 200F, which is the eco-following target vehicle 200E, accelerates, the drive unit 20 of the host vehicle 100 outputs a drive force (optimum drive force) that can be output with the maximum energy efficiency to accelerate the host vehicle 100. At this time, the drive unit of the preceding vehicle 200F also outputs a drive force (optimum drive force) that can be output with the maximum energy efficiency to accelerate the preceding vehicle 200F, and the drive force is the same as or close to the drive force output by the drive unit 20 of the host vehicle 100. Therefore, even if the host vehicle 100 is accelerated in this way, the host vehicle 100 runs following the preceding vehicle 200F. Therefore, even if the drive unit 20 is operated with high energy efficiency, the host vehicle 100 can be caused to run following the preceding vehicle 200F by the eco-following control.

[0115] The vehicle driving assistance device 10 executes normal driving control while it is determined that the driving assistance request condition Cass_req is not satisfied. The normal driving control is a control in which, when the accelerator pedal operation amount AP is greater than zero, a required driving torque (required driving force) is calculated based on the accelerator pedal operation amount AP and the driving speed (host vehicle speed V1) of the host vehicle 100, and the operation of the driving device 20 is controlled so that the required driving torque is output, and, when the brake pedal operation amount BP is greater than zero, a required braking torque (required braking force) is calculated based on the brake pedal operation amount BP, and the operation of the braking device 30 is controlled so that the required braking torque is output.

[0116] <Specific operation of the vehicle driving support device> Next, a specific operation of the vehicle driving support device 10 will be described. The CPU of the ECU 90 of the vehicle driving support device 10 executes the routine shown in Fig. 9 at a predetermined calculation cycle. Therefore, at a predetermined timing, the CPU starts the process from step 900 in Fig. 9, advances the process to step 905, and determines whether or not the execution of driving support control is requested (i.e., whether or not the driving support request condition Cass_req is satisfied).

[0117] If the CPU determines "Yes" in step 905, it proceeds to step 910 and determines whether or not execution of eco-driving support control has been requested (that is, whether or not the eco-driving request condition Ceco_req is satisfied).

[0118] If the CPU judges "Yes" in step 910, the process proceeds to step 915, where it judges whether or not the eco-tracking target vehicle 200E is present.

[0119] If the CPU determines "Yes" in step 915, the process proceeds to step 920, where it determines whether the preceding vehicle 200F is an eco-tracking target vehicle 200E.

[0120] If the CPU determines "Yes" in step 920, it proceeds to step 925 and determines whether the minimum front inter-vehicle distance DFmin and the minimum rear inter-vehicle distance DRmin can be ensured.

[0121] If the CPU judges "Yes" in step 925, it advances the process to step 930 and executes the routine shown in Fig. 10 or Fig. 11 to perform eco-following control. Therefore, if the CPU is configured to execute the routine shown in Fig. 10 when it advances the process to step 930, it starts the process from step 1000 in Fig. 10, advances the process to step 1005, and determines whether or not an adjustment of the vehicle distance is necessary.

[0122] If the CPU determines "Yes" in step 1005, the process proceeds to step 1010, where it executes the inter-vehicle distance adjustment control. The inter-vehicle distance adjustment control is the control for adjusting the inter-vehicle distance described above. After executing the inter-vehicle distance adjustment control, the CPU proceeds to step 995 in FIG. 9 via step 1095, and temporarily ends this routine.

[0123] On the other hand, if the CPU determines "No" in step 1005, it advances the process to step 1015 and determines whether or not there is information indicating that the eco-tracking target vehicle 200E has accelerated, based on the inter-vehicle communication information IV.

[0124] If the CPU determines "Yes" in step 1015, it proceeds to step 1020 and executes optimal acceleration control. After executing optimal acceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1095 and temporarily ends this routine.

[0125] On the other hand, if the CPU determines "No" in step 1015, it advances the process to step 1025 and determines whether or not there is information indicating that the eco-tracking target vehicle 200E has decelerated, based on the inter-vehicle communication information IV.

[0126] If the CPU determines "Yes" in step 1025, it proceeds to step 1030 and executes coasting deceleration control. After executing coasting deceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1095 and temporarily ends this routine.

[0127] On the other hand, if the CPU determines "No" in step 1025, it proceeds to step 1035 and executes steady-state running control. After executing constant-speed running control, the CPU proceeds to step 995 in Fig. 9 via step 1095 and temporarily ends this routine.

[0128] Alternatively, if the CPU is configured to execute the routine shown in FIG. 11 when the processing proceeds to step 930 in FIG. 9, the CPU starts the processing from step 1100 in FIG. 11, proceeds to step 1105, and determines whether or not a vehicle distance adjustment is necessary.

[0129] If the CPU determines "Yes" in step 1105, it proceeds to step 1110 and executes the following distance adjustment control. After executing the following distance adjustment control, the CPU proceeds to step 995 in Fig. 9 via step 1195 and temporarily ends this routine.

[0130] On the other hand, if the CPU determines "No" in step 1105, it advances the process to step 1115 and determines whether or not the eco-tracking target vehicle 200E has accelerated based on the surrounding detection information IS.

[0131] If the CPU determines "Yes" in step 1115, it proceeds to step 1120 and executes optimal acceleration control. After executing optimal acceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1195 and temporarily ends this routine.

[0132] On the other hand, if the CPU determines "No" in step 1115, it advances the process to step 1125 and determines whether or not the eco-tracking target vehicle 200E has decelerated based on the surrounding detection information IS.

[0133] If the CPU determines "Yes" in step 1125, it proceeds to step 1130 and executes coasting deceleration control. After executing coasting deceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1195 and temporarily ends this routine.

[0134] On the other hand, if the CPU determines "No" in step 1125, it proceeds to step 1135 and executes steady driving control. After executing steady driving control, the CPU proceeds to step 995 in Fig. 9 via step 1195 and temporarily ends this routine.

[0135] Also, when the CPU judges "No" at step 925 in Fig. 9, the CPU advances the process to step 950 and executes the routine shown in Fig. 12 to perform normal follow-up control. Therefore, when the CPU advances the process to step 950, the CPU starts the process from step 1200 in Fig. 12, advances the process to step 1205, and judges whether or not the follow-up acceleration condition CAacc is satisfied. In this example, as this judgment, the CPU judges whether or not the predicted arrival time TTC is longer than a predetermined predicted arrival time TTCref.

[0136] If the CPU determines "Yes" in step 1205, it proceeds to step 1210 and executes normal following acceleration control. In this example, the normal following acceleration control is a control that calculates a required acceleration Greq so that the speed at which the predicted arrival time TTC converges to a predetermined predicted arrival time TTCref (convergence speed) is equal to or faster than a predetermined speed, calculates a required driving force PDreq to achieve the required acceleration Greq, and controls the operation of the drive unit 20 so that the required driving force PDreq is output. After executing the normal following acceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1295 and temporarily ends this routine.

[0137] On the other hand, if the CPU determines "No" in step 1205, the process proceeds to step 1215, where it determines whether or not the following deceleration condition CDacc is satisfied. In this example, as this determination, the CPU determines whether or not the predicted arrival time TTC is shorter than a predetermined predicted arrival time TTCref.

[0138] If the CPU determines "Yes" in step 1215, it proceeds to step 1220 and executes normal following deceleration control. In this example, the normal following deceleration control is a control that calculates a required acceleration Greq so that the speed (convergence speed) at which the predicted arrival time TTC converges to a predetermined predicted arrival time TTCref is equal to or higher than a predetermined speed, calculates a required braking force PBreq to achieve the required acceleration Greq, and controls the operation of the braking device 30 so that the required braking force PBreq is output. After executing the normal following deceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1295 and temporarily ends this routine.

[0139] On the other hand, if the CPU determines "No" in step 1215, it proceeds to step 1225 and executes steady driving control. After executing steady driving control, the CPU proceeds to step 995 in Fig. 9 via step 1295 and temporarily ends this routine.

[0140] 9, the CPU advances the process to step 935 and executes the notification control described above.

[0141] Moreover, if the CPU determines “No” in step 915 , the process proceeds directly to step 940 .

[0142] When the CPU advances the process to step 940, it determines whether or not a preceding vehicle 200F exists and a following vehicle 200R exists.

[0143] If the CPU determines "Yes" in step 940, the process proceeds to step 950, where it executes the normal tracking control by executing the routine shown in Fig. 12. After executing the normal tracking control, the CPU proceeds to step 995, where it temporarily ends this routine.

[0144] On the other hand, if the CPU determines "No" at step 940, the process proceeds to step 945, where it determines whether or not the preceding vehicle 200F is present and the close distance ahead condition CFs is satisfied.

[0145] If the CPU determines "Yes" in step 945, the process proceeds to step 950, where it executes the normal tracking control by executing the routine shown in Fig. 12. After executing the normal tracking control, the CPU proceeds to step 995, where it temporarily ends this routine.

[0146] On the other hand, if the CPU determines "No" in step 945, the process proceeds to step 955, where it determines whether the preceding vehicle 200F is not present, the close rear distance condition CRs is satisfied, and the third acceleration allowable condition CAP3 is not satisfied. In this example, to make this determination, the CPU determines whether the forward inter-vehicle distance DF is longer than the preceding vehicle determination distance DFth, the rear inter-vehicle distance DR is equal to or smaller than the close rear distance determination value DRs, and the host vehicle speed V1 is equal to or larger than the upper limit value Vup2 of the second vehicle speed range R2.

[0147] If the CPU determines "Yes" in step 955, it advances the process to step 960 and executes the routine shown in Fig. 13 to perform normal constant speed control. Therefore, when the CPU advances the process to step 960, it starts the process from step 1300 in Fig. 13, advances the process to step 1305, and determines whether the constant speed acceleration condition CAcc is satisfied. In this example, as this determination, the CPU determines whether the host vehicle speed V1 is slower than the set vehicle speed Vset.

[0148] If the CPU determines "Yes" in step 1305, it proceeds to step 1310 and executes normal constant speed acceleration control. In this example, normal constant speed acceleration control is control that calculates a required acceleration Greq so that the speed at which the host vehicle speed V1 converges to the set vehicle speed Vset (convergence speed) is equal to or higher than a predetermined speed, calculates a required driving force PDreq to achieve the required acceleration Greq, and controls the operation of the drive device 20 so that the required driving force PDreq is output. After executing normal constant speed acceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1395 and temporarily ends this routine.

[0149] On the other hand, if the CPU determines "No" in step 1305, the process proceeds to step 1315, where it determines whether the constant speed deceleration condition CDcc is satisfied. In this example, as this determination, the CPU determines whether the host vehicle speed V1 is faster than the set vehicle speed Vset.

[0150] If the CPU determines "Yes" in step 1315, it proceeds to step 1320 and executes normal constant speed deceleration control. In this example, normal constant speed deceleration control is control that calculates a required acceleration Greq so that the speed at which the host vehicle speed V1 converges to the set vehicle speed Vset (convergence speed) is equal to or higher than a predetermined speed, calculates a required braking force PBreq to achieve the required acceleration Greq, and controls the operation of the braking device 30 so that the required braking force PBreq is output. After executing normal constant speed deceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1395 and temporarily ends this routine.

[0151] On the other hand, if the CPU determines "No" in step 1315, it proceeds to step 1325 and executes steady driving control. After executing steady driving control, the CPU proceeds to step 995 in Fig. 9 via step 1395 and temporarily ends this routine.

[0152] Moreover, if the CPU determines "No" at step 955 in Fig. 9, it advances the process to step 965 and executes the routine shown in Fig. 14 to perform eco-driving support control. Therefore, when the CPU advances the process to step 965, it starts the process from step 1400 in Fig. 14, advances the process to step 1405, and determines whether or not the following vehicle 200R is present. In this example, as this determination, the CPU determines whether or not the rear inter-vehicle distance DR is longer than the following vehicle determination distance DRth.

[0153] If the CPU determines "Yes" in step 1405, it proceeds to step 1410 and determines whether or not the preceding vehicle 200F is present. In this example, for this determination, the CPU determines whether or not the forward inter-vehicle distance DF is longer than the preceding vehicle determination distance DFth.

[0154] If the CPU determines "Yes" in step 1410, it proceeds to step 1415 and executes the routine shown in Fig. 15 to execute the first eco-driving support control (eco constant speed control). Therefore, when the CPU proceeds to step 1415, it starts the process from step 1500 in Fig. 15, and proceeds to step 1505 to determine whether or not the first deceleration condition CD1 is satisfied. In this example, as this determination, the CPU determines whether or not the host vehicle speed V1 is faster than the upper limit value Vup2 of the second vehicle speed range R2.

[0155] If the CPU determines "Yes" in step 1505, the process proceeds to step 1510, where it executes coasting deceleration control. After executing coasting deceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1595 and step 1495 in Fig. 14, and temporarily ends this routine.

[0156] On the other hand, if the CPU determines "No" in step 1505, the process proceeds to step 1515, where the CPU determines whether or not the first acceleration condition CA1 is satisfied. In this example, as this determination, the CPU determines whether or not the host vehicle speed V1 is slower than the lower limit value Vlow2 of the second vehicle speed range R2.

[0157] If the CPU determines "Yes" in step 1515, it proceeds to step 1520 and executes optimal acceleration control. After executing optimal acceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1595 and step 1495 in Fig. 14, and temporarily ends this routine.

[0158] On the other hand, if the CPU determines "No" in step 1515, it proceeds to step 1525 and executes steady driving control. After executing steady driving control, the CPU proceeds to step 995 in Fig. 9 via step 1595 and step 1495 in Fig. 14, and temporarily ends this routine.

[0159] Moreover, when the CPU judges "No" in step 1410 in Fig. 14, it advances the process to step 1420 and executes the routine shown in Fig. 16 to execute the second eco-driving control. Therefore, when the CPU advances the process to step 1420, it starts the process from step 1600 in Fig. 16, advances the process to step 1605, and judges whether or not the forward medium distance condition CFm is satisfied. In this example, as this judgment, the CPU judges whether or not the forward inter-vehicle distance DF is longer than the forward medium distance judgment value DFm.

[0160] If the CPU determines "Yes" in step 1605, the process proceeds to step 1610, where it determines whether or not the second deceleration condition CD2 is satisfied. In this example, for this determination, the CPU determines whether or not the host vehicle speed V1 is faster than the vehicle speed VF of the preceding vehicle 200F and the difference ΔVF between these vehicle speeds is greater than the forward approaching vehicle speed difference ΔVFa.

[0161] If the CPU determines "Yes" in step 1610, the process proceeds to step 1615, where it executes coasting deceleration control. After executing coasting deceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1695 and step 1495 in Fig. 14, and temporarily ends this routine.

[0162] On the other hand, if the CPU determines "No" in step 1610, the process proceeds to step 1620, where it determines whether or not the second acceleration condition CA2 is satisfied. In this example, for this determination, the CPU determines whether or not the host vehicle speed V1 is slower than the lower limit value Vlow2 of the second vehicle speed range R2, the host vehicle speed V1 is slower than the vehicle speed VF of the preceding vehicle 200F, and the difference ΔVF between these vehicle speeds is greater than the forward separation vehicle speed difference ΔVFb.

[0163] If the CPU determines "Yes" in step 1620, it proceeds to step 1625 and executes the optimal acceleration control. After executing the optimal acceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1695 and step 1495 in Fig. 14, and temporarily ends this routine.

[0164] On the other hand, if the CPU determines "No" in step 1620, the process proceeds to step 1630, where the CPU executes steady driving control. After executing steady driving control, the CPU proceeds to step 995 in Fig. 9 via step 1695 and step 1495 in Fig. 14, and temporarily ends this routine.

[0165] On the other hand, if the CPU determines "No" in step 1605, it proceeds to step 1635, where it executes coasting deceleration control. After executing coasting deceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1695 and step 1495 in Fig. 14, and temporarily ends this routine.

[0166] Moreover, when the CPU judges "No" in step 1405 of Fig. 14, it advances the process to step 1425 and executes the routine shown in Fig. 17 to execute the third eco-driving support control. Therefore, when the CPU advances the process to step 1425, it starts the process from step 1700 of Fig. 17, advances the process to step 1705, and judges whether or not the rear close distance condition CRs is satisfied. In this example, as this judgment, the CPU judges whether or not the rear inter-vehicle distance DR is longer than the rear close distance judgment value DRs.

[0167] If the CPU determines "Yes" in step 1705, the process proceeds to step 1710, where it determines whether or not the third acceleration condition CA3 is satisfied. In this example, for this determination, the CPU determines whether or not the host vehicle speed V1 is lower than the upper limit value Vup2 of the second vehicle speed range R2, the host vehicle speed V1 is slower than the vehicle speed VR of the following vehicle 200R, and the difference ΔVR between these vehicle speeds is larger than the rear approaching vehicle speed difference ΔVRa.

[0168] If the CPU determines "Yes" in step 1710, it proceeds to step 1715 and executes optimal acceleration control. After executing optimal acceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1795 and step 1495 in Fig. 14, and temporarily ends this routine.

[0169] On the other hand, if the CPU determines "No" in step 1710, it proceeds to step 1720 and executes steady driving control. After executing steady driving control, the CPU proceeds to step 995 in Fig. 9 via step 1795 and step 1495 in Fig. 14, and temporarily ends this routine.

[0170] On the other hand, if the CPU determines "No" in step 1705, it proceeds to step 1725 and executes the optimal acceleration control. After executing the optimal acceleration control, the CPU proceeds to step 995 in Fig. 9 via step 1795 and step 1495 in Fig. 14, and temporarily ends this routine.

[0171] 9, the CPU advances the process to step 970 to determine whether or not the preceding vehicle 200F is present. In this example, the CPU determines, as this determination, whether or not the forward inter-vehicle distance DF is equal to or less than the preceding vehicle determination distance DFth.

[0172] If the CPU determines "Yes" in step 970, the process proceeds to step 975, where it executes the normal tracking control by executing the routine shown in Fig. 12 described above. After executing the normal tracking control, the CPU proceeds to step 995, where it temporarily ends this routine.

[0173] On the other hand, if the CPU determines "No" in step 970, the process proceeds to step 980, where it executes the routine shown in Fig. 13 described above, thereby performing normal constant speed control. After executing normal constant speed control, the CPU proceeds to step 995 in Fig. 9, and temporarily ends this routine.

[0174] 9, the CPU proceeds directly to step 995 and temporarily ends this routine. In this case, the CPU executes normal driving control.

[0175] The specific operation of the vehicle driving assistance device 10 has been described above.

[0176] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. [Explanation of symbols]

[0177] Reference Signs List 10...vehicle driving assistance device, 20...driving device, 21...first power source, 22...second power source, 30...braking device, 51...driving assistance operation device, 52...eco-driving operation device, 60...peripheral information detection device, 61...radio wave sensor, 62...image sensor, 70...vehicle speed detection device, 81...transmitter / receiver, 90...ECU, 100...own vehicle, 200F...preceding vehicle, 200R...following vehicle, 200E...eco-following target vehicle< / ecu>

Claims

1. A vehicle driving support device that executes follow-up control for automatically controlling an acceleration / deceleration of a host vehicle to make the host vehicle follow a preceding vehicle, and when accelerating the host vehicle, causes a drive device of the host vehicle to output a drive force that can be output with maximum efficiency, thereby accelerating the host vehicle, the drive device of the host vehicle includes at least two power sources each having a different driving force that can be output with maximum efficiency, The drive device of the preceding vehicle also includes at least two power sources each having a different drive force that can be output with maximum efficiency, a maximum efficiency control is being executed in the preceding vehicle, in which a driving force that can be output with maximum efficiency by the driving device of the preceding vehicle is output from the driving device of the preceding vehicle to accelerate the preceding vehicle, and the following control is executed when a difference between a driving force that can be output with maximum efficiency by one of the power sources of the preceding vehicle and a driving force that can be output with maximum efficiency by one of the power sources of the host vehicle is equal to or less than a predetermined value, and a difference between a driving force that can be output with maximum efficiency by the other of the power sources of the preceding vehicle and a driving force that can be output with maximum efficiency by the other of the power sources of the host vehicle is also equal to or less than the predetermined value. In a vehicle driving assistance device, a maximum efficiency control is executed to accelerate the vehicle by outputting the driving force that can be output with maximum efficiency from the driving device of the vehicle, and when a target vehicle is present, the target vehicle is a vehicle in which a difference between the driving force that one of the power sources of the vehicle can output with maximum efficiency and the driving force that one of the power sources of the vehicle can output with maximum efficiency is equal to or less than the predetermined value, and a difference between the driving force that the other of the power sources of the vehicle can output with maximum efficiency and the driving force that the other of the power sources of the vehicle can output with maximum efficiency is also equal to or less than the predetermined value, the notification control is executed to notify the driver of the target vehicle of the presence of the target vehicle. Vehicle driving assistance device.

2. A vehicle driving assistance device that executes follow-up control for automatically controlling acceleration / deceleration of a host vehicle to cause the host vehicle to follow a preceding vehicle, and when accelerating the host vehicle, executes follow-up control for accelerating the host vehicle by outputting from the drive device of the host vehicle a driving force that can be output with maximum efficiency by the drive device of the host vehicle, a maximum efficiency control is executed in the preceding vehicle, in which a driving force that can be outputted with maximum efficiency by the driving device of the preceding vehicle is outputted from the driving device of the preceding vehicle to accelerate the preceding vehicle, and the following control is executed when a difference between the driving force that can be outputted with maximum efficiency by the driving device of the preceding vehicle and a driving force that can be outputted with maximum efficiency by the driving device of the host vehicle is equal to or less than a predetermined value; In a vehicle driving assistance device, a maximum efficiency control is executed to accelerate the vehicle by outputting a driving force that the driving device of the vehicle can output with maximum efficiency from the driving device of the vehicle, and when a target vehicle exists, the target vehicle is a vehicle in which the difference between the driving force that the driving device of the vehicle can output with maximum efficiency and the driving force that the driving device of the vehicle can output with maximum efficiency is equal to or less than the predetermined value, the notification control is executed to notify the driver of the vehicle of the presence of the target vehicle. Vehicle driving assistance device.

3. In the vehicle driving assistance device according to claim 1 or claim 2, and when the preceding vehicle is decelerating due to coasting while the maximum efficiency control is being executed in the preceding vehicle, the following control is executed so as to decelerate the subject vehicle by coasting when the preceding vehicle decelerates. Vehicle driving assistance device.

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