Vehicle driving assistance device, vehicle driving assistance method, and vehicle driving assistance program

Abstract

Provided is a vehicle driving assistance device capable of obtaining a constant energy consumption reduction effect in accordance with a driving mode. A vehicle driving assistance device (10) is configured to be capable of executing autonomous travel control for causing a host vehicle (100) to autonomously travel in a first travel mode, power control in a first state in which loss of power generated by the power device (20) or loss of power transmission from the power device to the drive wheel is reduced, and power control in a second state in which the power device is mechanically or electrically connected to the drive wheel to apply power to the drive wheel are selectively performed. The control value of the own vehicle is increased or decreased within the set control range. In the autonomous travel control in the first travel mode, when the drive mode is a first drive mode in which power other than power generated by the electric power of the electricity storage device (41) can be used, the setting control range is set to be larger than when the drive mode is a second drive mode in which only power generated by the electric power is used.

Description

Technical Field

[0001] The present invention relates to a vehicle driving assistance device, a vehicle driving assistance method and a vehicle driving assistance program. Background Art

[0002] A vehicle driving assistance device is known that performs autonomous driving control to autonomously control the operation of a power unit of a vehicle so that the vehicle's speed increases or decreases within a set speed range, or so that the distance between the vehicle and a preceding vehicle increases or decreases within a set distance range, thereby driving the vehicle (see, for example, Patent Document 1). This vehicle driving assistance device aims to reduce the amount of energy consumed by the power unit (energy consumption) by driving the vehicle using this autonomous driving control. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-95320 Summary of the Invention

[0004] As means for achieving the above-mentioned autonomous driving control, there is a means of causing the own vehicle to inertially drive when the speed of the own vehicle reaches the upper limit of the set speed range, and causing the own vehicle to run under power when the speed of the own vehicle reaches the lower limit of the set speed range. In addition, there is a means of causing the own vehicle to inertially drive when the vehicle distance between the own vehicle and the preceding vehicle reaches the lower limit of the set vehicle distance range, and causing the own vehicle to run under power when the vehicle distance between the own vehicle and the preceding vehicle reaches the upper limit of the set vehicle distance range.

[0005] Furthermore, when the power unit includes an internal combustion engine and an electric motor, it is possible to selectively execute power-operated driving of the own vehicle in a hybrid drive mode in which the own vehicle is powered by power output from at least one of the internal combustion engine and the electric motor, and power-operated driving of the own vehicle in a motor drive mode in which the own vehicle is powered only by power output from the electric motor.

[0006] In this way, when executing autonomous driving control, in the case of selectively executing power running driving in hybrid driving mode and power running driving in motor driving mode, the energy consumption reduction effect when executing power running driving in hybrid driving mode to execute autonomous driving control is different from the energy consumption reduction effect when executing power running driving in motor driving mode to execute autonomous driving control.

[0007] An object of the present invention is to provide a vehicle driving assistance device, a vehicle driving assistance method, and a vehicle driving assistance program that can achieve a constant energy consumption reduction effect according to a driving mode.

[0008] A vehicle driving assistance device according to the present invention includes a control device configured to execute autonomous driving control for causing a vehicle to autonomously drive in a first driving mode. In this first driving mode, the control device selectively executes power control in a first state in which power generation losses in a power unit or power transmission losses from the power unit to drive wheels are reduced, and in a second state in which the power unit is mechanically or electrically connected to the drive wheels to apply power to the drive wheels, thereby increasing or decreasing a control value for the vehicle within a set control range. Furthermore, the control device is configured to set the set control range to a larger range during the execution of the autonomous driving control in the first driving mode when the driving mode is a first driving mode in which power other than power generated by electric power from a power storage device can be used, compared to when the driving mode is a second driving mode in which only power generated by electric power is used.

[0009] When the vehicle is autonomously driven in the first driving mode using autonomous driving control, the energy consumption reduction effect generally increases when the control range is set to a larger range. However, when the vehicle is autonomously driven in the second driving mode, the energy consumption reduction effect is not significantly increased even when the control range is set to a larger range.

[0010] According to the vehicle driving assistance device of the present invention, when the vehicle is autonomously driven using autonomous driving control in the first driving mode, the control range is set to a larger range when the driving mode is the first driving mode than when the driving mode is the second driving mode. Therefore, a consistent energy consumption reduction effect can be achieved depending on the driving mode.

[0011] Furthermore, in the vehicle driving assistance device according to the present invention, for example, when the own vehicle autonomously travels by the autonomous travel control in the first drive mode, the set control range can be changed by a setting operation performed by the driver of the own vehicle.

[0012] According to the vehicle driving assistance device according to the present invention, the driver can arbitrarily set the control range.

[0013] In addition, in the vehicle driving assistance device involved in the present invention, the control device can be configured to, when the self-vehicle is driving autonomously through the autonomous driving control in the first driving mode, if an abnormality occurs in the subsequent vehicle detection device that detects the subsequent vehicle, the set control range is set to a smaller range compared to when the subsequent vehicle detection device is normal.

[0014] If a following vehicle is present while the own vehicle is autonomously traveling under autonomous driving control in the first driving mode, and the own vehicle's speed increases or decreases excessively, or the distance between the own vehicle and the preceding vehicle increases or decreases excessively, the following vehicle will significantly increase or decrease its speed, potentially disrupting the smooth flow of surrounding vehicles, including the following vehicle. Therefore, to maintain smooth flow of surrounding vehicles, it is desirable to autonomously travel the own vehicle under autonomous driving control in the first driving mode while the own vehicle is autonomously traveling under autonomous driving control in the first driving mode, taking into account the presence of the following vehicle. However, to achieve this, a following vehicle detection device is required. However, if the following vehicle detection device fails to detect the following vehicle due to, for example, a malfunction, autonomous driving control cannot be executed while taking into account the presence of the following vehicle. Consequently, autonomous driving control in the first driving mode cannot be used to autonomously travel the own vehicle in a manner that maintains smooth flow of surrounding vehicles.

[0015] According to the vehicle driving assistance device of the present invention, if a following vehicle detection device experiences an abnormality, the control range is set to a narrower range than when the following vehicle detection device is normal. This maintains control values ​​such as the vehicle speed and the distance between the vehicle and the preceding vehicle within a narrow range, thereby preventing excessive fluctuations in the vehicle speed or the distance between the vehicle and the preceding vehicle. Therefore, even if a following vehicle cannot be detected, the vehicle can still be driven autonomously using autonomous driving control in the first driving mode without disrupting the smooth flow of surrounding vehicles.

[0016] Furthermore, in the vehicle driving assistance device according to the present invention, the control device may be configured to execute the autonomous driving control in a second driving mode in which the control value is maintained at a set control value. In this case, the control device may be configured to switch the autonomous driving control mode from the first driving mode to the second driving mode if a driving mode switching condition is satisfied during the execution of the autonomous driving control in the first driving mode: the following vehicle detection device is normal, detects the following vehicle, and the distance between the following vehicle and the host vehicle is less than a predetermined distance, or the time required for the host vehicle to travel the distance between the following vehicle and the host vehicle is less than a predetermined time.

[0017] When there is a following vehicle while the own vehicle is driving autonomously through autonomous driving control in the first driving mode, if the speed of the own vehicle increases or decreases too much, or the inter-vehicle distance between the own vehicle and the preceding vehicle increases or decreases too much, the following vehicle will increase or decrease its speed significantly, which may hinder the smooth traffic of surrounding vehicles including the following vehicle.

[0018] According to the vehicle driving assistance device of the present invention, when a following vehicle is relatively close to the host vehicle, that is, when the driving mode switching condition is met, the autonomous driving control mode is switched from the first driving mode to the second driving mode. This maintains the host vehicle's speed constant, and the distance between the host vehicle and the preceding vehicle is also maintained constant. Therefore, even when a following vehicle is relatively close to the host vehicle, the host vehicle can be autonomously driven in a manner that maintains smooth traffic flow for surrounding vehicles.

[0019] Furthermore, in the vehicle driving assistance device according to the present invention, for example, the set control range when executing the autonomous driving control in the second driving mode is set to a smaller range than when executing the autonomous driving control in the first driving mode. In this case, the control device may be configured not to change the set control range even if an abnormality occurs in the following vehicle detection device during the execution of the autonomous driving control in the second driving mode.

[0020] According to the vehicle driving assistance device involved in the present invention, when the self-vehicle is autonomously driven by autonomous driving control in the second driving mode, the set control range is set to a smaller range. Therefore, if the following vehicle detection device has an abnormality and cannot detect the following vehicle, even if the self-vehicle continues to autonomously drive by autonomous driving control without changing the set control range, the speed of the self-vehicle will not increase or decrease excessively, or the distance between the self-vehicle and the preceding vehicle will not increase or decrease excessively. Therefore, the following vehicle will not increase or decrease its speed significantly. Therefore, the possibility of obstructing the smooth traffic of surrounding vehicles is small. Therefore, the self-vehicle can be autonomously driven by autonomous driving control in a manner that maintains the smooth traffic of surrounding vehicles without changing the set control range.

[0021] Furthermore, in the vehicle driving assistance device according to the present invention, the control device may be configured to, when a first condition is satisfied, discontinue the autonomous driving control in the first driving mode and execute the autonomous driving control using the power control in the first state. In this case, the first condition is, for example, set to a condition that is more likely to be satisfied when the vehicle is traveling downhill and is more likely to be satisfied when the vehicle is autonomously traveling using the autonomous driving control in the first driving mode than when the vehicle is autonomously traveling using the autonomous driving control in the second driving mode.

[0022] When the vehicle is traveling downhill, even if the vehicle is autonomously traveling in the first state, the vehicle's speed tends to increase, so there is no need to autonomously travel in the second state to increase the vehicle's speed. Therefore, when the vehicle is traveling downhill, autonomously traveling in the first state achieves a greater energy consumption reduction effect than autonomously traveling in the second state. Furthermore, when autonomously traveling in the first driving mode in the first driving mode, not autonomously traveling in the second state achieves a greater energy consumption reduction effect than autonomously traveling in the first driving mode in the second driving mode.

[0023] According to the vehicle driving assistance device of the present invention, the first condition is a condition that is easily satisfied when the vehicle is traveling downhill. That is, the first condition makes it easier for the vehicle to discontinue autonomous driving control in the first driving mode and execute autonomous driving control in the first state when the vehicle is traveling downhill. Furthermore, the first condition is set to be a condition that is less likely to be satisfied when the vehicle is autonomously traveling under autonomous driving control in the second driving mode than when the vehicle is autonomously traveling under autonomous driving control in the first driving mode. That is, the first condition makes it more difficult for the vehicle to discontinue autonomous driving control in the first driving mode and execute autonomous driving control in the first state when the vehicle is autonomously traveling under autonomous driving control in the second driving mode. Therefore, a significant reduction in energy consumption can be achieved.

[0024] In addition, in the vehicle driving assistance device according to the present invention, the control device may be configured to execute the autonomous driving control in the constant speed mode to maintain the speed of the own vehicle at a set speed. In this case, the control device may be configured to terminate the autonomous driving control in the first driving mode and execute the autonomous driving control in the constant speed mode when a second condition is satisfied. In this case, the second condition is, for example, set to a condition that is easily satisfied when the own vehicle is traveling on an uphill road or when the own vehicle is traveling at a speed greater than a specified speed, and is more likely to be satisfied when the own vehicle is autonomously driven by the autonomous driving control in the first driving mode than when the own vehicle is autonomously driven by the autonomous driving control in the second driving mode.

[0025] When the vehicle is traveling uphill or at high speed, if the vehicle is driven autonomously in the first mode, the vehicle's speed may be significantly reduced. Furthermore, even if the vehicle is driven autonomously in the second mode, the vehicle's speed may not be increased appropriately. Therefore, when the vehicle is traveling uphill or at high speed, if the vehicle is driven autonomously using autonomous driving control in the first driving mode, the energy consumption reduction effect is reduced.

[0026] Moreover, when the own vehicle is driven autonomously by the autonomous driving control in the first driving mode, the control range is set to a larger range than when the own vehicle is driven autonomously by the autonomous driving control in the second driving mode. Therefore, when the own vehicle is driving on an uphill road or when the own vehicle is driving at a high speed, if the own vehicle is driven autonomously by the autonomous driving control in the first driving mode and the first driving mode, the energy consumption reduction effect will decrease.

[0027] According to the vehicle driving assistance device of the present invention, the second condition is set to be a condition that is more likely to be met when the vehicle is traveling uphill or at a speed exceeding a predetermined speed, and is more likely to be met when the vehicle is autonomously traveling under autonomous driving control in the first driving mode than when the vehicle is autonomously traveling under autonomous driving control in the second driving mode. Furthermore, if the second condition is met, autonomous driving control in the first driving mode is discontinued and autonomous driving control in the constant speed mode is executed. In other words, when the vehicle is traveling uphill or at a speed exceeding a predetermined speed, and autonomous driving control in the first driving mode and in the first driving mode is being used to autonomously travel, autonomous driving control in the first driving mode is more likely to be discontinued and autonomous driving control in the constant speed mode is executed. Thus, a consistent energy consumption reduction effect can be ensured.

[0028] Furthermore, a vehicle driving assistance method according to the present invention is a method for executing autonomous driving control to cause a vehicle to autonomously drive in a first driving mode. In this first driving mode, power control is selectively executed in a first state in which power generation loss in a power unit or power transmission loss from the power unit to drive wheels is reduced, and in a second state in which the power unit is mechanically or electrically connected to the drive wheels to apply power to the drive wheels, thereby increasing or decreasing a control value of the vehicle within a set control range. Furthermore, the vehicle driving assistance method according to the present invention includes the step of, during the execution of the autonomous driving control in the first driving mode, setting the set control range to a larger range when the driving mode is a first driving mode in which power other than power generated by electric power from a power storage device can be used, compared to when the driving mode is a second driving mode in which only power generated by electric power is used.

[0029] According to the vehicle driving support method according to the present invention, for the same reasons as described above, it is possible to obtain a constant energy consumption reduction effect according to the driving mode.

[0030] Furthermore, a vehicle driving assistance program according to the present invention is a program for executing autonomous driving control to cause a vehicle to autonomously drive in a first driving mode. In this first driving mode, power control is selectively executed in a first state in which power generation loss in a power unit or power transmission loss from the power unit to the drive wheels is reduced, and in a second state in which the power unit is mechanically or electrically connected to the drive wheels to apply power to the drive wheels, thereby increasing or decreasing a control value of the vehicle within a set control range. Furthermore, the vehicle driving assistance program according to the present invention is configured such that, during the execution of the autonomous driving control in the first driving mode, when the driving mode is the first driving mode in which power other than power generated by electric power from a power storage device can be used, the set control range is set to a larger range than when the driving mode is the second driving mode in which only power generated by electric power is used.

[0031] According to the vehicle driving support program according to the present invention, for the same reasons as described above, it is possible to obtain a constant energy consumption reduction effect according to the driving mode.

[0032] 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 additional advantages of the present invention can be easily understood from the description of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a diagram showing a vehicle driving assistance device according to an embodiment of the present invention.

[0034] Figure 2A This is a diagram showing a scenario in which there is a preceding vehicle ahead of the own vehicle.

[0035] Figure 2B This diagram shows a scenario in which there is no preceding vehicle in front of the own vehicle.

[0036] Figure 3A The diagram shows a scenario in which there is no preceding vehicle in front of the own vehicle and there is a following vehicle behind the own vehicle.

[0037] Figure 3B The diagram shows a scene in which a preceding vehicle exists in front of the own vehicle and a following vehicle exists behind the own vehicle.

[0038] Figure 4 This is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention.

[0039] Figure 5This is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention.

[0040] Figure 6 This is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention.

[0041] Figure 7 This is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention.

[0042] Figure 8 This is a time chart showing changes in the road gradient and the vehicle's own speed when the economic autonomous driving control is terminated and the normal vehicle speed control is executed.

[0043] Figure 9 This is a time chart showing changes in the road gradient and the vehicle's own speed when normal vehicle speed control is executed after the economic autonomous driving control is terminated and the coasting control is executed.

[0044] Figure 10 This is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention.

[0045] Figure 11 This is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention.

[0046] Figure 12 This is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention.

[0047] Figure 13 This is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. DETAILED DESCRIPTION

[0048] Hereinafter, a vehicle driving assistance device, a vehicle driving assistance method, and a vehicle driving assistance program according to embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 , a vehicle driving assistance device 10 is shown. The vehicle driving assistance device 10 is mounted on a vehicle 100. The vehicle driving assistance device 10 will be described below using as an example a case where the operator of the vehicle 100 is a person riding in and driving the vehicle 100 (i.e., the driver of the vehicle 100).

[0049] However, the operator of the own vehicle 100 may also be a person who is not riding in the own vehicle 100 but is remotely driving the own vehicle 100 (i.e., a remote operator of the own vehicle 100). In the case where the operator of the own vehicle 100 is a remote operator, the vehicle driving assistance device 10 is mounted on the own vehicle 100 and on a remote operation device installed outside the own vehicle 100 for remote driving of the own vehicle 100. The functions of the vehicle driving assistance device 10 described below are shared by the vehicle driving assistance device 10 mounted on the own vehicle 100 and the vehicle driving assistance device 10 mounted on the remote operation device.

[0050] like Figure 1 As shown, the vehicle driving assistance device 10 includes an ECU (electronic control unit) 90 as a control device. The ECU 90 includes a microcomputer as its main component. The microcomputer includes a CPU, storage media such as ROM, RAM, and non-volatile memory, as well as interfaces, etc. The CPU implements various functions by executing instructions, programs, or routines stored in the storage media. In particular, in this example, the vehicle driving assistance device 10 stores programs that implement the various controls performed by the vehicle driving assistance device 10 in the storage medium.

[0051] Furthermore, the vehicle driving assistance device 10 may also be configured to be able to update the program stored in the recording medium through wireless communication with an external device (eg, Internet communication).

[0052] like Figure 1 As shown, the vehicle 100 is equipped with a power unit 20 and a brake system 30. The power unit 20 is a device that generates power to be applied to the vehicle 100 (particularly, the drive wheels of the vehicle 100), and in this example, includes an internal combustion engine 21 and an electric motor 22. Furthermore, the brake system 30 is a device that applies braking force to the vehicle 100 (particularly, the wheels of the vehicle 100), and in this example, includes a hydraulic brake system 31. The internal combustion engine 21, the electric motor 22, and the hydraulic brake system 31 are electrically connected to the ECU 90. The vehicle driving assistance device 10 can control the operation of the internal combustion engine 21, the electric motor 22, and the hydraulic brake system 31.

[0053] The vehicle 100 is also equipped with a power storage device 41, such as a battery, and a charge level sensor 42. The electric motor 22 operates using the electricity stored in the power storage device 41. Furthermore, the electric motor 22 generates electricity using the power output from the internal combustion engine 21, and charges the generated electricity into the power storage device 41. The charge level sensor 42 detects the amount of electricity charged into the power storage device 41. The charge level sensor 42 is electrically connected to the ECU 90. The vehicle driving assistance device 10 detects the amount of electricity charged into the power storage device 41 using the charge level sensor 42.

[0054] The vehicle 100 is further equipped with a surrounding information detection device 50. The surrounding information detection device 50 is a device that obtains information about the surroundings of the vehicle 100 as surrounding information detection information IS. In this example, the surrounding information detection device 50 includes a front information detection device 51 and a rear information detection device 52.

[0055] The forward information detection device 51 includes a forward electromagnetic wave sensor 511, such as a radar sensor, and a forward image sensor 512, such as a camera sensor. The forward electromagnetic wave sensor 511 and the forward image sensor 512 are electrically connected to the ECU 90. The vehicle driving assistance device 10 obtains data regarding an object in front of the host vehicle 100 (forward object information IF_O) as forward detection information IF via the forward electromagnetic wave sensor 511. Furthermore, the vehicle driving assistance device 10 obtains image data (forward image information IF_C) in front of the host vehicle 100 as forward detection information IF via the forward image sensor 512.

[0056] The vehicle driving assistance device 10 detects the preceding vehicle 200 based on the front target information IF_O and / or the front image information IF_C, and then obtains the preceding vehicle distance DF. Figure 2A As shown, the preceding vehicle 200 is another vehicle traveling in the own vehicle driving lane LN1 and traveling ahead of the own vehicle 100 at a predetermined distance from the own vehicle 100. The preceding vehicle distance DF is the distance (inter-vehicle distance) between the own vehicle 100 and the preceding vehicle 200.

[0057] The rear information detection device 52 also includes a rear electromagnetic wave sensor 521, such as a radar sensor, and a rear image sensor 522, such as a camera sensor. The rear electromagnetic wave sensor 521 and the rear image sensor 522 are electrically connected to the ECU 90. The vehicle driving assistance device 10 obtains data related to objects behind the own vehicle 100 (rear object information IR_O) as rear detection information IR via the rear electromagnetic wave sensor 521. Furthermore, the vehicle driving assistance device 10 obtains image data (rear image information IR_C) of the area behind the own vehicle 100 as rear detection information IR via the rear image sensor 522.

[0058] The vehicle driving assistance device 10 detects the following vehicle 300 based on the rear target information IR_O and / or the rear image information IR_C, and then obtains the following vehicle distance DR. Figure 3A and Figure 3BAs shown, the following vehicle 300 is another vehicle traveling in the own vehicle driving lane LN1 and traveling behind the own vehicle 100 at a predetermined distance from the own vehicle 100. The following vehicle distance DR is the distance (inter-vehicle distance) between the own vehicle 100 and the following vehicle 300.

[0059] <Overview of Operation of Vehicle Driving Assistance Device>

[0060] Next, an overview of the operation of the vehicle driving support device 10 will be described.

[0061] The vehicle driving assistance device 10 is configured to be capable of executing autonomous driving control (such as the economic vehicle speed control or the economic vehicle distance control described later) that enables the own vehicle 100 to autonomously drive in a first driving mode. In this first driving mode, power control in a first state in which power generation loss in the power unit 20 or power transmission loss from the power unit 20 to the drive wheels is reduced (such as the coasting control described later), and power control in a second state in which the power unit 20 is mechanically or electrically connected to the drive wheels to apply power to the drive wheels (such as the optimal power operation control described later) are selectively executed to increase or decrease the control value of the own vehicle 100 (such as the own vehicle speed V, the preceding vehicle distance DF, or the preceding vehicle arrival time TF described later) within a set control range (such as the set vehicle speed range R_V, the set preceding vehicle distance range R_DF, or the set preceding vehicle arrival time TF_S described later).

[0062] In this example, mechanically connecting the power unit 20 to the drive wheels to apply power to the drive wheels means inputting power output from the internal combustion engine 21 to the drive wheels of the vehicle 100, thereby causing the vehicle 100 to travel. Furthermore, in this example, electrically connecting the power unit 20 to apply power to the drive wheels means inputting power output from the electric motor 22 to the drive wheels of the vehicle 100, thereby causing the vehicle 100 to travel.

[0063] In addition, the vehicle driving assistance device 10 is configured to be able to perform autonomous driving control (such as the normal vehicle speed control or the normal vehicle distance control described later) in a second driving mode in which the control value of the own vehicle 100 (such as the own vehicle speed V, the preceding vehicle distance DF, or the preceding vehicle arrival time TF described later) is maintained at a set control value (such as the set vehicle speed V_S, the set preceding vehicle distance DF_S, or the set preceding vehicle arrival time TF_S described later).

[0064] In addition, the vehicle driving assistance device 10 is configured to select, as a driving mode for the own vehicle 100, one of a first driving mode (for example, a hybrid driving mode described later) in which a power other than the power generated by the electricity of the storage device can be used as the power for driving the own vehicle 100, and a second driving mode (for example, a motor driving mode described later) in which only the power generated by the above-mentioned electricity is used, and can selectively perform autonomous driving control in the first driving mode and autonomous driving control in the second driving mode.

[0065] In other words, the vehicle driving assistance device 10 is configured to selectively execute speed increase / decrease control (such as the economic speed control described later) in which the speed of the own vehicle 100 is increased or decreased within a set speed range while the own vehicle 100 drives autonomously, and vehicle distance increase / decrease control (such as the economic vehicle distance control described later) in which the vehicle distance between the own vehicle 100 and other vehicles around the own vehicle 100 (such as the preceding vehicle 200) is increased or decreased within a set vehicle distance range or the time required for the own vehicle 100 to travel the above-mentioned vehicle distance is increased or decreased within a set time range while the own vehicle 100 drives autonomously.

[0066] In addition, the vehicle driving assistance device 10 is configured to selectively execute speed maintenance control (such as the normal speed control described later) for maintaining the speed of the own vehicle 100 at a set speed while allowing the own vehicle 100 to drive autonomously, and vehicle distance maintenance control (such as the normal vehicle distance control described later) for maintaining the vehicle distance between the own vehicle 100 and other vehicles around the own vehicle 100 (such as the preceding vehicle 200) at a set vehicle distance or maintaining the time required for the own vehicle 100 to travel the above-mentioned vehicle distance at a set time while allowing the own vehicle 100 to drive autonomously.

[0067] In addition, the vehicle driving assistance device 10 is configured to be able to perform vehicle speed increase and decrease control and vehicle distance increase and decrease control (such as the economic vehicle speed control and economic vehicle distance control described later) in a first driving mode (such as the hybrid driving mode described later) in which both the internal combustion engine 21 and the electric motor 22 or only the internal combustion engine 21 are operated to apply power to the own vehicle 100 to cause the own vehicle 100 to move, and in a second driving mode (such as the motor driving mode described later) in which only the electric motor 22 is operated to apply power to the own vehicle 100 to cause the own vehicle 100 to move.

[0068] In addition, the vehicle driving assistance device 10 is configured to selectively perform power control in a first state in which power generation loss in the power unit 20 of the own vehicle 100 or power transmission loss from the power unit 20 to the drive wheels of the own vehicle 100 is reduced (for example, the coasting control described later), and power control in a second state in which the power unit 20 is mechanically or electrically connected to the drive wheels to apply power to the drive wheels (for example, the optimal power operation control described later) to perform vehicle speed increase and decrease control and vehicle distance increase and decrease control (for example, the economical vehicle speed control and economical vehicle distance control described later).

[0069] In addition, in this example, the vehicle driving assistance device 10 reduces the amount of energy consumed in the internal combustion engine 21 to generate power (engine energy consumption) by stopping the operation of the internal combustion engine 21, or reduces the amount of energy consumed to generate power by the electric motor 22 (motor energy consumption) by stopping the power supply from the storage device 41 to the electric motor 22, thereby achieving a first state in which the power generation loss in the power unit 20 is reduced.

[0070] In addition, in this example, the vehicle driving assistance device 10 can achieve a first state in which the power transmission loss from the power unit 20 to the drive wheels is reduced by cutting off the power transmission path from the power unit 20 to the drive wheels of the own vehicle 100 by making the so-called clutch into a non-connected state.

[0071] Furthermore, in this example, the vehicle driving assistance device 10 establishes a transmission path from the power unit 20 to the drive wheels of the vehicle 100, and applies power from the internal combustion engine 21 to the drive wheels of the vehicle 100 via this transmission path, thereby achieving a second state in which the power unit 20 is mechanically coupled to the drive wheels of the vehicle 100 and power is applied to the drive wheels. More specifically, the vehicle driving assistance device 10 achieves the second state in which the power unit 20 is mechanically coupled to the drive wheels of the vehicle 100 and power is applied to the drive wheels by executing optimal power operation control, which will be described later.

[0072] In addition, in this example, the vehicle driving assistance device 10 realizes a second state of electrically connecting the power unit 20 to the drive wheels and applying power to the drive wheels by establishing a transmission path from the power unit 20 to the drive wheels of the own vehicle 100 and applying power from the electric motor 22 to the drive wheels of the own vehicle 100 via the transmission path.

[0073] Next, the control executed by the vehicle driving assistance device 10 will be described in more detail, taking as an example a case where another vehicle around the own vehicle 100 is the preceding vehicle 200 .

[0074] The vehicle driving assistance device 10 performs autonomous driving control as automatic driving control or autonomous driving control. Autonomous driving control is control that accelerates and decelerates the vehicle 100 by autonomously controlling the operation of the power unit 20 and the brake system 30, thereby driving the vehicle 100. In this example, autonomous driving control includes inter-vehicle distance control and vehicle speed control.

[0075] like Figure 2A As shown, inter-vehicle distance control is executed when a preceding vehicle 200 is ahead of the host vehicle 100 and autonomously accelerates or decelerates the host vehicle 100 based on a set preceding vehicle distance DF_S. The set preceding vehicle distance DF_S is the preceding vehicle distance DF set by the driver as a control target under inter-vehicle distance control.

[0076] Alternatively, inter-vehicle distance control is executed when a preceding vehicle 200 is ahead of the host vehicle 100. It autonomously accelerates or decelerates the host vehicle 100 based on a set preceding vehicle arrival time TF_S. Set preceding vehicle arrival time TF_S is the preceding vehicle arrival time TF set by the driver as the control target for inter-vehicle distance control. The preceding vehicle arrival time TF is calculated by dividing the preceding vehicle distance DF by the host vehicle speed V (TF = DF / V). Therefore, the preceding vehicle arrival time TF represents the time required for the host vehicle 100 to travel the preceding vehicle distance DF.

[0077] More specifically, the vehicle distance control includes normal vehicle distance control and economic vehicle distance control.

[0078] Normal inter-vehicle distance control is a type of normal autonomous driving control, causing the vehicle 100 to autonomously drive while maintaining the preceding vehicle distance DF at a set preceding vehicle distance DF_S. Alternatively, normal inter-vehicle distance control can also be a control that causes the vehicle 100 to autonomously drive while maintaining the preceding vehicle arrival time TF at the set preceding vehicle arrival time TF_S. Therefore, normal inter-vehicle distance control is what is known as follow-up driving control or adaptive cruise control.

[0079] Furthermore, the vehicle driving assistance device 10 may be configured to execute normal vehicle speed control (constant speed control) described below when the vehicle speed V increases and reaches the set vehicle speed V_S during execution of the normal inter-vehicle distance control.

[0080] Economical inter-vehicle distance control is a type of economical autonomous driving control. It involves coasting the vehicle 100 when the preceding vehicle distance DF decreases and reaches the lower limit (lower preceding vehicle distance DF_L) of a predetermined range (set preceding vehicle distance range R_DF), and then powering the vehicle 100 when the preceding vehicle distance DF increases and reaches the upper limit (upper preceding vehicle distance DF_U) of the predetermined preceding vehicle distance range R_DF. This control allows the vehicle 100 to autonomously travel while increasing or decreasing the preceding vehicle distance DF within the predetermined preceding vehicle distance range R_DF. In other words, economical inter-vehicle distance control alternates between powering and coasting the vehicle 100 while allowing the preceding vehicle distance DF to vary within the predetermined range (set preceding vehicle distance range R_DF).

[0081] Alternatively, economical distance control involves coasting the vehicle 100 when the preceding vehicle arrival time TF decreases and reaches the lower limit (lower preceding vehicle time TF_L) of a predetermined range (set preceding vehicle time range R_TF), and then power running control (optimal power running control) that starts power running the vehicle 100 when the preceding vehicle arrival time TF increases and reaches the upper limit (upper preceding vehicle time TF_U) of the predetermined preceding vehicle time range R_TF. This allows the vehicle 100 to autonomously travel while increasing or decreasing the preceding vehicle arrival time TF within the predetermined preceding vehicle time range R_TF. In other words, economical distance control alternates between power running and coasting the vehicle 100 while allowing the preceding vehicle arrival time TF to vary within the predetermined range (set preceding vehicle time range R_TF).

[0082] Furthermore, in this example, the set preceding vehicle distance range R_DF is set to include the set preceding vehicle distance DF_S. More specifically, the set preceding vehicle distance range R_DF is set by setting an inter-vehicle distance greater than the set preceding vehicle distance DF_S by a predetermined value (the control inter-vehicle distance width dD) as the upper limit preceding vehicle distance DF_U (DF_U = DF_S + dD), and setting an inter-vehicle distance less than the set preceding vehicle distance DF_S by a predetermined value (the control inter-vehicle distance width dD) as the lower limit preceding vehicle distance DF_L (DF_L = DF_S - dD).

[0083] In this example, the set preceding vehicle time range R_TF is set to include the set preceding vehicle arrival time TF_S. More specifically, the set preceding vehicle time range R_TF is set by setting the upper limit preceding vehicle time TF_U (TF_U = TF_S + dT) to a time greater than the set preceding vehicle arrival time TF_S by a predetermined value (controlling the preceding vehicle arrival time width dT), and setting the lower limit preceding vehicle time TF_L (TF_L = TF_S - dT) to a time less than the set preceding vehicle arrival time TF_S by a predetermined value (controlling the preceding vehicle arrival time width dT).

[0084] Optimal power running control controls the operation of the power unit 20 so that power is output from the power unit 20 at maximum or near-maximum energy efficiency, specifically operating the internal combustion engine 21 at its optimal operating point (or a point near the optimal operating point). Coasting control controls the operation of the power unit 20 so that the vehicle 100 coasts.

[0085] On the other hand, Figure 2B As shown, vehicle speed control is executed when there is no preceding vehicle 200, and autonomously controls the travel speed of own vehicle 100 (own vehicle speed V) using set vehicle speed V_S as a reference. Set vehicle speed V_S is the travel speed of own vehicle 100 (own vehicle speed V) set by the driver as a control target under vehicle speed control.

[0086] like Figure 1 As shown, a vehicle speed detection device 61 such as a wheel speed sensor is mounted on the vehicle 100. The vehicle speed detection device 61 is electrically connected to the ECU 90. The vehicle driving support device 10 obtains the vehicle speed V of the vehicle through the vehicle speed detection device 61.

[0087] More specifically, the vehicle speed control includes normal vehicle speed control and economical vehicle speed control.

[0088] The normal vehicle speed control is one type of normal autonomous driving control, and is a control for causing the vehicle 100 to autonomously drive while maintaining the vehicle speed V at the set vehicle speed V_S. Therefore, the normal vehicle speed control is a so-called constant speed control or cruise control.

[0089] Economical speed control is a control that causes vehicle 100 to autonomously travel while increasing or decreasing its own vehicle speed V within the set speed range R_V. This control initiates coasting control when vehicle speed V increases and reaches the upper limit (upper limit vehicle speed V_U) of a predetermined range (set speed range R_V), and initiates optimal power running control when vehicle speed V decreases and reaches the lower limit (lower limit vehicle speed V_L) of the set speed range R_V. In other words, economical speed control alternately performs power running and coasting of vehicle 100 while allowing vehicle speed V to fluctuate within the predetermined range (set speed range R_V).

[0090] Furthermore, in this example, the set vehicle speed range R_V is set to include the set vehicle speed V_S. More specifically, the set vehicle speed range R_V is established by setting the vehicle speed greater than the set vehicle speed V_S by a predetermined value (the control speed width dV) as the upper limit vehicle speed V_U (V_U = V_S + dV), and setting the vehicle speed less than the set vehicle speed V_S by a predetermined value (the control speed width dV) as the lower limit vehicle speed V_L (V_L = V_S - dV).

[0091] <Specific Operation of Vehicle Driving Assistance Device>

[0092] Next, the specific operation of the vehicle driving assistance device 10 will be described. The vehicle driving assistance device 10 executes the operation in a predetermined calculation cycle. Figure 4 The routine shown is used to perform autonomous driving control.

[0093] When a predetermined timing comes, the vehicle driving assistance device 10 Figure 4 The process of the routine shown starts at step S400 , and the process proceeds to step S405 , where it is determined whether the normal autonomous driving condition C1 is satisfied.

[0094] Normally, autonomous driving condition C1 is a condition where autonomous driving enable condition C2 is met, autonomous driving control is requested, and economic autonomous driving control (eco-driving control) is not requested. Economic autonomous driving control includes economic vehicle speed control and economic inter-vehicle distance control. Furthermore, economic autonomous driving control causes the vehicle 100 to coast in a pulsed manner.

[0095] Furthermore, autonomous driving enable condition C2 may include, for example, the normal functioning of systems required for autonomous driving control, such as the normal functioning of the surrounding information detection device 50, or the condition that the road on which the vehicle 100 is traveling is not in a situation where the slope is not high enough to determine that execution of economic autonomous driving control is undesirable. Furthermore, the normal autonomous driving condition C1 may not include the condition that autonomous driving enable condition C2 is satisfied.

[0096] In addition, if Figure 1 As shown, the vehicle 100 is equipped with an autonomous driving request operator 71, such as a driving assist button, and an economic autonomous driving request operator 72, such as an economic driving button. The autonomous driving request operator 71 and the economic autonomous driving request operator 72 are electrically connected to the ECU 90. By operating the autonomous driving request operator 71, the driver can request the vehicle driving assistance device 10 to execute autonomous driving control. Furthermore, by operating the economic autonomous driving request operator 72, the driver can request the vehicle driving assistance device 10 to execute economic autonomous driving control.

[0097] When the determination in step S405 is “YES”, the vehicle driving assistance device 10 advances the process to step S410 to determine whether or not the preceding vehicle 200 exists.

[0098] If the determination in step S410 is "YES," the vehicle driving assistance device 10 proceeds to step S415, where it executes normal inter-vehicle distance control as autonomous driving control. Next, the vehicle driving assistance device 10 proceeds to step S420, where it sets the value of the economic autonomous driving flag X_ECO to "0." The process then proceeds to step S495, temporarily terminating the present routine.

[0099] On the other hand, if the determination in step S410 is "No," the vehicle driving assistance device 10 proceeds to step S425, where it executes normal vehicle speed control as autonomous driving control. Next, the vehicle driving assistance device 10 proceeds to step S430, where it sets the value of the economic autonomous driving flag X_ECO to "0," and then proceeds to step S495, temporarily terminating the processing of this routine.

[0100] Furthermore, when the determination in step S405 is “NO”, the vehicle driving assistance device 10 advances the process to step S435 to determine whether the economic autonomous driving condition C3 is satisfied.

[0101] The economic autonomous driving condition C3 is a condition that the autonomous driving enabling condition C2 is satisfied, the autonomous driving control is requested, and the economic autonomous driving control is requested. The economic autonomous driving condition C3 may not include the autonomous driving enabling condition C2.

[0102] When the determination in step S435 is “YES”, the vehicle driving support device 10 advances the process to step S440 to determine whether a power running condition C4 described later is satisfied.

[0103] If the determination result in step S440 is "Yes", the vehicle driving assistance device 10 proceeds to step S445 to execute Figure 7This routine will be described later.

[0104] On the other hand, if the determination in step S440 is "No", the vehicle driving assistance device 10 proceeds to step S450 to execute Figure 5 or Figure 6 The routine shown.

[0105] Therefore, when the vehicle driving assistance device 10 advances the process to step S450, Figure 5 In the case of the routine shown, from Figure 5 The process of the illustrated routine starts at step S500 , and the process proceeds to step S505 , where it is determined whether or not the preceding vehicle 200 exists.

[0106] If the vehicle driving assistance device 10 determines "YES" in step S505, the process proceeds to step S510 to execute economical inter-vehicle distance control as autonomous driving control. Next, the vehicle driving assistance device 10 proceeds to step S515 to set the value of the economical autonomous driving flag X_ECO to "1." The process then proceeds to step S595, temporarily terminating the processing of this routine.

[0107] On the other hand, if the determination in step S505 is "No," the vehicle driving assistance device 10 proceeds to step S520 to execute the economical vehicle speed control as autonomous driving control. Next, the vehicle driving assistance device 10 proceeds to step S525 to set the value of the economic autonomous driving flag X_ECO to "1." The process then proceeds to step S595, temporarily terminating the processing of this routine.

[0108] Alternatively, when the vehicle driving assistance device 10 advances the process to step S450, Figure 6 In the case of the routine shown, from Figure 6 The process of the illustrated routine starts at step S600 , and the process proceeds to step S605 , where it is determined whether or not the preceding vehicle 200 exists.

[0109] When the determination in step S605 is “YES”, the vehicle driving assistance device 10 advances the process to step S607 to determine whether the following vehicle distance DR is greater than a predetermined distance (approach determination distance DR_N).

[0110] Furthermore, the vehicle driving assistance device 10 may be configured to determine, in step S607, whether the following vehicle arrival time TR is longer than a predetermined time (approach determination time TR_N). The following vehicle arrival time TR is a value obtained by dividing the following vehicle distance DR by the speed of the following vehicle 300 (the following vehicle speed VR) (TR = DR / VR). Therefore, the following vehicle arrival time TR is the time required for the following vehicle 300 to travel the following vehicle distance DR.

[0111] If the vehicle driving assistance device 10 determines "YES" in step S607, the process proceeds to step S610 to execute economical inter-vehicle distance control as autonomous driving control. Next, the vehicle driving assistance device 10 proceeds to step S615 to set the value of the economical autonomous driving flag X_ECO to "1." The process then proceeds to step S695, temporarily terminating the processing of this routine.

[0112] On the other hand, if the vehicle driving assistance device 10 determines "No" in step S607, the process proceeds to step S616, where it discontinues economical inter-vehicle distance control and executes normal inter-vehicle distance control. Next, the vehicle driving assistance device 10 proceeds to step S617, where it sets the value of the economical autonomous driving flag X_ECO to "0." The process then proceeds to step S695, temporarily terminating the processing of this routine.

[0113] In this way, the vehicle driving assistance device 10 is configured to be able to execute normal inter-vehicle distance control (autonomous driving control in the second driving mode in which the control value is maintained at the set control value) in which the preceding vehicle distance DF is maintained at the set preceding vehicle distance DF_S, and is configured to, during the execution of economic inter-vehicle distance control (autonomous driving control in the first driving mode), when the condition that the following vehicle distance DR is less than the approach determination distance DR_N or the following vehicle arrival time TR is less than the approach determination time TR_N (a driving mode switching condition in which the following vehicle detection device for detecting the following vehicle 300 is normal, and the following vehicle 300 is detected, and the distance between the following vehicle 300 and the own vehicle 100 is less than the prescribed distance, or the time required for the own vehicle 100 to travel the distance between the following vehicle 300 and the own vehicle 100 is less than the prescribed time) is met, the control for causing the own vehicle 100 to drive autonomously (the mode in which the own vehicle 100 drives autonomously) is switched from economic inter-vehicle distance control to normal inter-vehicle distance control (switching from the first driving mode to the second driving mode).

[0114] When the vehicle 100 is autonomously traveling by economical distance control and there is a following vehicle 300, if the preceding vehicle distance DF increases or decreases excessively, the following vehicle 300 will increase or decrease its speed significantly, which may hinder the smooth traffic of surrounding vehicles including the following vehicle 300.

[0115] According to the vehicle driving assistance device 10, when the following vehicle 300 is relatively close to the host vehicle 100, the control for autonomous driving of the host vehicle 100 is switched from economical inter-vehicle distance control to normal inter-vehicle distance control. This maintains the preceding vehicle distance DF constant. Therefore, even when the following vehicle 300 is relatively close to the host vehicle 100, the host vehicle 100 can be autonomously driven while maintaining smooth traffic flow for surrounding vehicles.

[0116] In addition, the vehicle driving assistance device 10 is configured to perform normal vehicle distance control (vehicle distance maintenance control) in which the preceding vehicle distance DF (vehicle distance) is maintained at the set preceding vehicle distance DF_S (set vehicle distance) or the preceding vehicle arrival time TF (the time required for the own vehicle 100 to travel the vehicle distance between the own vehicle 100 and the surrounding vehicles) is maintained at the set preceding vehicle arrival time TF_S (set time) while the own vehicle 100 autonomously drives. In addition, the vehicle driving assistance device 10 is configured to terminate the economical vehicle distance control (vehicle distance increase and decrease control) and execute the normal vehicle distance control (vehicle distance maintenance control) when the condition that the subsequent vehicle distance DR is less than the approach determination distance DR_N or the subsequent vehicle arrival time TR is less than the approach determination time TR_N is met (the driving mode switching condition that the subsequent vehicle detection device that detects the subsequent vehicle 300 is normal, and the subsequent vehicle 300 is detected, and the distance between the subsequent vehicle 300 and the own vehicle 100 is less than the prescribed distance or the time required for the own vehicle 100 to travel the distance between the subsequent vehicle 300 and the own vehicle 100 is less than the prescribed time) is met during the execution of the economical vehicle distance control (vehicle distance increase and decrease control).

[0117] When the vehicle 100 is autonomously traveling by economical distance control and there is a following vehicle 300, if the preceding vehicle distance DF increases or decreases excessively, the following vehicle 300 will increase or decrease its speed significantly, which may hinder the smooth traffic of surrounding vehicles including the following vehicle 300.

[0118] According to the vehicle driving assistance device 10, when the following vehicle 300 is relatively close to the host vehicle 100, economical inter-vehicle distance control is suspended and normal inter-vehicle distance control is executed. This maintains the preceding vehicle distance DF constant. Therefore, even when the following vehicle 300 is relatively close to the host vehicle 100, the host vehicle 100 can autonomously drive while maintaining smooth traffic flow for surrounding vehicles.

[0119] On the other hand, when the determination in step S605 is “NO”, the vehicle driving assistance device 10 advances the process to step S618 to determine whether the following vehicle distance DR is greater than the approach determination distance DR_N.

[0120] Furthermore, the vehicle driving assistance device 10 may also be configured to determine, in step S618 , whether the subsequent vehicle arrival time TR is longer than the approach determination time TR_N.

[0121] If the determination in step S618 is "YES," the vehicle driving assistance device 10 proceeds to step S620 to execute economical vehicle speed control as autonomous driving control. Next, the vehicle driving assistance device 10 proceeds to step S625 to set the value of the economic autonomous driving flag X_ECO to "1." The process then proceeds to step S695, temporarily terminating the present routine.

[0122] On the other hand, if the determination in step S618 is "No," the vehicle driving assistance device 10 proceeds to step S626, where it discontinues the economical vehicle speed control and executes the normal vehicle speed control. Next, the vehicle driving assistance device 10 proceeds to step S627, where it sets the value of the economical autonomous driving flag X_ECO to "0," and then proceeds to step S695, temporarily terminating the processing of this routine.

[0123] In this way, the vehicle driving assistance device 10 is configured to be able to execute normal vehicle speed control (autonomous driving control of the own vehicle 100 in the second driving mode in which the control value is maintained at the set control value) to maintain the own vehicle speed V at the set vehicle speed V_S, and is configured to, during the execution of the economic vehicle speed control (autonomous driving control in the first driving mode), when the condition that the subsequent vehicle distance DR is less than the approach determination distance DR_N or the subsequent vehicle arrival time TR is less than the approach determination time TR_N (a driving mode switching condition in which the subsequent vehicle detection device for detecting the subsequent vehicle 300 is normal and the subsequent vehicle 300 is detected, and the distance between the subsequent vehicle 300 and the own vehicle 100 is less than the prescribed distance or the time required for the own vehicle 100 to travel the distance between the subsequent vehicle 300 and the own vehicle 100 is less than the prescribed time) is satisfied, the control for causing the own vehicle 100 to drive autonomously (the mode for causing the own vehicle 100 to drive autonomously) is switched from the economic vehicle speed control to the normal vehicle speed control (switching from the first driving mode to the second driving mode).

[0124] When the own vehicle 100 is autonomously traveling under the economical speed control and there is a following vehicle 300, if the own vehicle speed V increases or decreases excessively, the following vehicle 300 will also increase or decrease its speed significantly, which may hinder the smooth traffic of surrounding vehicles including the following vehicle 300.

[0125] According to the vehicle driving assistance device 10, when the following vehicle 300 is relatively close to the host vehicle 100, the control for autonomous driving of the host vehicle 100 is switched from economical speed control to normal speed control. This maintains the host vehicle speed V constant. Therefore, even when the following vehicle 300 is relatively close to the host vehicle 100, the host vehicle 100 can be autonomously driven while maintaining smooth traffic flow for surrounding vehicles.

[0126] The vehicle driving assistance device 10 is configured to execute normal vehicle speed control (vehicle speed maintenance control) for autonomously driving the host vehicle 100 while maintaining the host vehicle speed V at a set vehicle speed V_S. Furthermore, the vehicle driving assistance device 10 is configured to terminate the economical vehicle speed control (vehicle speed increase / decrease control) and execute normal vehicle speed control (vehicle speed maintenance control) if, during execution of the economical vehicle speed control (vehicle speed increase / decrease control), the following vehicle distance DR is less than the approach determination distance DR_N or the following vehicle arrival time TR is less than the approach determination time TR_N. (Driving mode switching condition: the following vehicle detection device for detecting the following vehicle 300 is normal, the following vehicle 300 is detected, and the distance between the following vehicle 300 and the host vehicle 100 is less than a predetermined distance, or the time required for the host vehicle 100 to travel the distance between the following vehicle 300 and the host vehicle 100 is less than a predetermined time.)

[0127] When the own vehicle 100 is autonomously traveling under the economical speed control and there is a following vehicle 300, if the own vehicle speed V increases or decreases excessively, the following vehicle 300 will also increase or decrease its speed significantly, which may hinder the smooth traffic of surrounding vehicles including the following vehicle 300.

[0128] According to the vehicle driving assistance device 10, when the following vehicle 300 is relatively close to the host vehicle 100, the economical speed control is suspended and the normal speed control is executed. As a result, the host vehicle speed V is maintained constant. Therefore, even when the following vehicle 300 is relatively close to the host vehicle 100, the host vehicle 100 can be driven autonomously while maintaining smooth traffic flow for surrounding vehicles.

[0129] In addition, the vehicle driving assistance device 10 Figure 4 If a "NO" determination is made in step S435 of the illustrated routine, the process proceeds to step S455, where normal vehicle speed control is executed. Thereafter, the process proceeds to step S495, and the process of this routine is temporarily terminated.

[0130] Then, Figure 7 The following example illustrates the routine shown.

[0131] Figure 4 The power running condition C4 determined in step S440 of the illustrated routine is that the value of the economic autonomous driving flag X_ECO is "1" and optimal power running control is being executed. In other words, the power running condition C4 is that no deceleration of the vehicle 100 is requested during the execution of the economic autonomous driving control.

[0132] The vehicle driving assistance device 10 is Figure 4 If the determination in step S440 of the routine shown is "Yes" and the process proceeds to step S445, Figure 7 The process of the routine shown starts at step S700 , and the process proceeds to step S705 , where it is determined whether the value of the hybrid drive mode flag X_HV is “1”.

[0133] The value of the hybrid drive mode flag X_HV is set to "1" when the vehicle 100 is currently traveling in the hybrid drive mode, and is set to "0" when the vehicle 100 is not currently traveling in the hybrid drive mode. The hybrid drive mode is a mode in which the vehicle 100 is driven by operating both the internal combustion engine 21 and the electric motor 22, or by operating only the internal combustion engine 21, in accordance with the required power P_REQ. The required power P_REQ is the power required to be output from the power unit 20.

[0134] If the vehicle driving assistance device 10 determines "YES" in step S705, the process proceeds to step S710, where the inefficiency index threshold IX_T is set to the first inefficiency index threshold IX1, and the coasting acceleration threshold G_T is set to the first coasting acceleration threshold G1, and the process proceeds to step S725. The inefficiency index threshold IX_T is used in the determination of step S725, and the coasting acceleration threshold G_T is used in the determination of step S735, which will be described later.

[0135] On the other hand, when the determination in step S705 is “NO”, the vehicle driving assistance device 10 advances the process to step S715 to determine whether the value of the motor drive mode flag X_EV is “1”.

[0136] The value of the motor drive mode flag X_EV is set to "1" when the vehicle 100 is currently traveling in the motor drive mode, and is set to "0" when the vehicle 100 is not currently traveling in the motor drive mode. The motor drive mode is a mode in which only the electric motor 22 is operated to cause the vehicle 100 to travel.

[0137] If the vehicle driving assistance device 10 determines "YES" in step S715, the process proceeds to step S720, where the inefficiency index threshold IX_T is set to the second inefficiency index threshold IX2, and the coasting acceleration threshold G_T is set to the second coasting acceleration threshold G2, and the process proceeds to step S725. Furthermore, the second inefficiency index threshold IX2 is set to a value greater than the first inefficiency index threshold IX1, and the second coasting acceleration threshold G2 is set to a value greater than the first coasting acceleration threshold G1.

[0138] After advancing the process to step S725 , the vehicle driving assistance device 10 determines whether the low efficiency condition C5 is satisfied.

[0139] The low-efficiency condition C5 is that, when the economic autonomous driving control (economic inter-vehicle distance control or economic vehicle speed control) for driving the own vehicle 100 while switching the driving of the own vehicle 100 between idling control and optimal power operation control is executed, the driving energy efficiency (the energy efficiency in the power unit 20 involved in the driving of the own vehicle 100) is lower than the driving energy efficiency when the own vehicle 100 is driven by the normal vehicle speed control, taking into account the slope of the road on which the own vehicle 100 is traveling (road slope θ).

[0140] In this example, the low efficiency condition C5 is as shown in the following equation 1, which is a condition that the low efficiency index IX is greater than the low efficiency index threshold IX_T.

[0141] IX>IXth…(1)

[0142] The inefficiency index IX is an index indicating the degree of reduction in the energy efficiency associated with the travel of the own vehicle 100 (travel energy efficiency) when the economic autonomous travel control is executed, relative to the energy efficiency associated with the travel of the own vehicle 100 when the normal vehicle speed control is executed.

[0143] In this example, the inefficiency index IX is obtained by calculation according to the following formula 2.

[0144] IX=|Gd|-k×|Ga|…(2)

[0145] Gd=-F / M+g×sinθ…(3)

[0146] Ga=(P_OPT-F) / M+g×sinθ…(4)

[0147] In Equation 2, "Gd" is the acceleration of the vehicle 100 (coasting acceleration) achieved when coasting control is executed, and is obtained by calculation according to Equation 3. Coasting acceleration Gd is obtained as a negative value when the vehicle speed V decreases, and as a positive value when the vehicle speed V increases.

[0148] In Equation 2, "Ga" represents the acceleration of the vehicle 100 achieved when optimal power running control is executed (optimal power running acceleration), and is obtained by calculation according to Equation 4. Optimum power running acceleration Ga is also obtained as a negative value when the vehicle speed V decreases and as a positive value when the vehicle speed V increases.

[0149] In Equations 3 and 4, "F" represents the running resistance of the vehicle 100, which is obtained, for example, by calculation according to Equation 5 below. Furthermore, "M" represents the weight of the vehicle 100, "g" represents the acceleration due to gravity, and "θ" represents the road surface gradient. Furthermore, "P_OPT" represents the power applied by the power unit 20 to the vehicle 100 during optimal power operation control (optimum power operation power).

[0150] F=a×V 2 +b×V+c…(5)

[0151] In Formula 5, “V” is the traveling speed of the own vehicle 100 (own vehicle speed), and “a”, “b”, and “c” are coefficients determined so as to accurately obtain the traveling resistance of the own vehicle 100 based on the own vehicle speed V.

[0152] The inefficiency index thresholds IX_T (the first inefficiency index threshold IX1 and the second inefficiency index threshold IX2) are predetermined values, and "k" in Equation 1 is a coefficient set to a predetermined value. These inefficiency index thresholds IX_T and the coefficient k are set as follows.

[0153] That is, when the own vehicle 100 is traveling on a flat road, while the own vehicle 100 is traveling by economic autonomous driving control (economic inter-vehicle distance control or economic vehicle speed control) that controls the traveling of the own vehicle 100 while switching between inertial control and optimal power operation control, inertial control is performed when the own vehicle 100 is required to decelerate, so the driving energy efficiency becomes higher compared to the case where the own vehicle 100 is traveling by normal vehicle speed control.

[0154] However, when the vehicle 100 is traveling uphill using the economic autonomous driving control, the switching between coasting control and optimal power running control is frequently performed over a certain period of time. Therefore, the driving energy efficiency may be reduced compared to the case where the vehicle 100 is traveling using normal vehicle speed control. In particular, when the vehicle 100 is autonomously traveling in the hybrid drive mode, the internal combustion engine 21 is frequently started and stopped, which increases the likelihood of a reduction in driving energy efficiency.

[0155] Therefore, in this example, when the inefficiency index IX is obtained through calculations according to Equations 2 to 4, a combination of an inefficiency index threshold value IX_T and a coefficient k is determined in advance through experiments, etc., in the relationship between the road gradient θ, the coasting acceleration Gd, and the optimal power running acceleration Ga, so that the driving energy efficiency when the vehicle 100 is driven under economic autonomous driving control is equal to the driving energy efficiency when the vehicle 100 is driven under normal vehicle speed control. These inefficiency index threshold values ​​IX_T and the coefficient k are used in Equations 1 and 2, respectively. In this example, the coefficient k is set to a value greater than "0" and less than or equal to "1."

[0156] Therefore, when the inefficiency index IX is greater than the inefficiency index threshold IX_T, the driving energy efficiency of the own vehicle 100 is higher when the own vehicle 100 is driven by the normal vehicle speed control than when the own vehicle 100 is driven by the economic autonomous driving control.

[0157] Based on the above, it can be said that the vehicle driving assistance device 10 determines in step S725 whether it is more energy efficient to continue the economic autonomous driving control or to terminate the economic autonomous driving control and execute the normal vehicle speed control.

[0158] Furthermore, low-efficiency condition C5 can also be considered an uphill slope condition in which the road gradient θ is greater than a predetermined uphill slope threshold θup during execution of economic autonomous driving control. Furthermore, in this case, the predetermined uphill slope threshold θup can be considered to be the slope at which the absolute value of the deceleration of the vehicle 100 when the vehicle 100 is traveling under coasting control on an uphill road gradient θ becomes greater than or equal to a predetermined value (predetermined deceleration threshold). Alternatively, the predetermined uphill slope threshold θup can be considered to be the slope at which the acceleration / deceleration of the vehicle 100 when the vehicle 100 is traveling under optimal power running control on an uphill road gradient θ becomes greater than or equal to a predetermined value (predetermined acceleration threshold). Alternatively, the predetermined uphill slope threshold θup can be considered to be the slope at which the absolute value of the coasting acceleration Gd relative to the optimal power running acceleration Ga when the road gradient θ is uphill becomes greater than a predetermined ratio.

[0159] Furthermore, in order to prevent the vehicle driving control from frequently switching between the economic autonomous driving control and the normal vehicle speed control, hysteresis may be provided for the inefficiency index threshold value IX_T.

[0160] In addition, after the low efficiency condition C5 is met and the vehicle driving control is switched from the economic autonomous driving control to the normal vehicle speed control, if it is determined that there is a leading vehicle 200 during the execution of the normal vehicle speed control, the vehicle driving control is switched from the normal vehicle speed control to the normal vehicle distance control.

[0161] Furthermore, after the vehicle's driving control is switched from economic autonomous driving control to normal vehicle speed control when the low-efficiency condition C5 is satisfied, the vehicle's driving control is switched from normal vehicle speed control to economic autonomous driving control when the low-efficiency condition C5 no longer satisfies it. Specifically, in this example, economic autonomous driving control is temporarily terminated when the low-efficiency condition C5 is satisfied, and then resumed when the low-efficiency condition C5 no longer satisfies it. However, economic autonomous driving control may also be terminated when the low-efficiency condition C5 is satisfied, and then not resumed even if the low-efficiency condition C5 no longer satisfies it.

[0162] In addition, if Figure 1 As shown, the vehicle 100 is equipped with a road gradient acquisition device 62. The road gradient acquisition device 62 is a device that acquires the gradient of the road on which the vehicle 100 is traveling, and is, for example, a gyroscopic sensor. The road gradient acquisition device 62 is electrically connected to the ECU 90. The vehicle driving assistance device 10 uses the road gradient acquisition device 62 to acquire the gradient of the road on which the vehicle 100 is traveling as the road gradient θ.

[0163] When the determination in step S725 is “YES”, the vehicle driving assistance device 10 advances the process to step S730 to execute normal vehicle speed control, and then advances the process to step S795 to temporarily terminate the processing of this routine.

[0164] As described above, the vehicle driving assistance device 10 is configured to execute normal vehicle speed control (autonomous driving control in constant speed mode) to maintain the vehicle speed V at the set speed V_S. Furthermore, the vehicle driving assistance device 10 is configured to terminate the economic autonomous driving control (autonomous driving control in the first driving mode) and execute normal vehicle speed control (autonomous driving control in constant speed mode) when the low-efficiency condition C5 (second condition) is satisfied. Furthermore, the low-efficiency condition C5 (second condition) is a condition that is likely to be satisfied when the vehicle 100 is traveling uphill or at a relatively high speed (when the vehicle 100 is traveling at a speed above a predetermined speed). Furthermore, the low-efficiency index threshold IX_T is set to the first low-efficiency index threshold IX1 when the vehicle 100 is traveling in the hybrid drive mode (first drive mode), and to the second low-efficiency index threshold IX2 when the vehicle 100 is traveling in the motor drive mode (second drive mode). The first low-efficiency index threshold IX1 is a value smaller than the second low-efficiency index threshold IX2. Therefore, the low-efficiency condition C5 (second condition) is set to a condition that is more likely to be met when the own vehicle 100 is driven autonomously by economic autonomous driving control in the hybrid drive mode (first drive mode) than when the own vehicle 100 is driven autonomously by economic autonomous driving control in the motor drive mode (second drive mode).

[0165] If the vehicle 100 is driven autonomously using coasting control while traveling uphill or at high speed, the vehicle speed V may decrease significantly. Furthermore, even if the vehicle 100 is driven autonomously using optimal power running control, the vehicle speed V may not be increased appropriately. Therefore, if the vehicle 100 is driven autonomously using economical autonomous driving control while traveling uphill or at high speed, the energy consumption reduction effect is reduced.

[0166] Moreover, when the own vehicle 100 is driven autonomously by the economic autonomous driving control in the hybrid drive mode, the set vehicle speed range R_V or the set preceding vehicle distance range R_DF is set to a larger range than when the own vehicle 100 is driven autonomously by the economic autonomous driving control in the motor drive mode. Therefore, when the own vehicle 100 is traveling on an uphill road or when the own vehicle 100 is traveling at a high speed, if the own vehicle 100 is driven autonomously by the economic autonomous driving control in the hybrid drive mode, the energy consumption reduction effect will be reduced.

[0167] According to the vehicle driving assistance device 10, the low-efficiency condition C5 is set to a condition that is more likely to be met when the vehicle 100 is traveling uphill or at high speed, and is more likely to be met when the vehicle 100 is autonomously traveling using the economic autonomous driving control in the hybrid drive mode than when the vehicle 100 is autonomously traveling using the economic autonomous driving control in the motor drive mode. Furthermore, if the low-efficiency condition C5 is met, the economic autonomous driving control is discontinued and normal vehicle speed control is executed. In other words, when the vehicle 100 is traveling uphill or at high speed using the economic autonomous driving control in the hybrid drive mode, the economic autonomous driving control is more likely to be discontinued and normal vehicle speed control is executed. This ensures a consistent reduction in energy consumption.

[0168] In addition, according to the vehicle driving assistance device 10, the own vehicle speed V is as follows Figure 8 is controlled as shown. Figure 8 In the example shown, until time t50, the vehicle 100 is traveling on a road with a road gradient θ of zero, i.e., a flat road, and optimal power running control is being executed. Consequently, the vehicle speed V gradually increases until time t50. Furthermore, the optimal power running acceleration Ga and the coasting acceleration Gd at this time are the first optimal power running acceleration Ga1 and the first coasting acceleration Gd1, respectively. The first optimal power running acceleration Ga1 is a positive value, while the first coasting acceleration Gd1 is a negative value.

[0169] Then, at time t50, when the vehicle speed V reaches the upper limit speed V_U, coasting control begins. At this time, the vehicle 100 is traveling on a flat road with a road gradient θ of zero. Consequently, the vehicle speed V begins to decrease. Furthermore, the optimal power running acceleration Ga and coasting acceleration Gd at this time are also the first optimal power running acceleration Ga1 and the first coasting acceleration Gd1, respectively.

[0170] Then, at time t51, the vehicle 100 starts traveling on the uphill road. Figure 8In the example shown, the road gradient θ continuously increases from time t51 to time t53, and then reaches a constant value θ1 after time t53. Therefore, from time t51 to time t53, the optimal power running acceleration Ga and the coasting acceleration Gd gradually decrease. In other words, the absolute value of the optimal power running acceleration Ga gradually decreases, while the absolute value of the coasting acceleration Gd gradually increases. Then, after time t53, the optimal power running acceleration Ga and the coasting acceleration Gd remain constant at the second optimal power running acceleration Ga2 and the second coasting acceleration Gd2, respectively.

[0171] After time t51, the vehicle speed V continues to decrease. Figure 8 In the example shown, at time t52, low-efficiency condition C5 is satisfied, economic autonomous driving control ends, and normal vehicle speed control begins. At this time, because the vehicle speed V is less than the set speed V_S, the vehicle 100 accelerates, increasing its speed. After reaching the set speed V_S, the acceleration of the vehicle 100 is controlled to maintain the speed V at the set speed V_S.

[0172] Thus, when the low efficiency condition C5 is satisfied during the execution of the economic autonomous driving control, the economic autonomous driving control is terminated and the normal vehicle speed control is executed. This prevents a decrease in driving energy efficiency caused by continued execution of the economic autonomous driving control.

[0173] On the other hand, when the determination in step S725 is “NO”, the vehicle driving assistance device 10 advances the process to step S735 to determine whether the coasting acceleration condition C6 is satisfied.

[0174] Coasting acceleration condition C6 is the condition that the vehicle 100 is traveling on a gently sloping downhill road. In this example, coasting acceleration condition C6 is the condition that coasting acceleration Gd is greater than zero as shown in equation 6 below, and the absolute value of coasting acceleration Gd is greater than or equal to coasting acceleration threshold value G_T as shown in equation 7 below.

[0175] Gd>0…(6)

[0176] |Gd|≧G_T…(7)

[0177] Coasting acceleration threshold G_T is used to determine whether the vehicle 100 is traveling on a gently sloping downhill road. In this example, it is set to a positive value close to 0. Therefore, coasting acceleration condition C6 can also be considered a downhill gradient condition, where the road gradient θ is greater than a predetermined value (predetermined downhill gradient threshold θdown).

[0178] When the determination in step S735 is “YES”, the vehicle driving assistance device 10 advances the process to step S740 to determine whether the traveling speed condition C7 is satisfied.

[0179] The traveling speed condition C7 is a condition that the own vehicle speed V is less than the set vehicle speed V_S as shown in the following equation 8.

[0180] V <V_S…(8)

[0181] When the determination in step S740 is “YES”, the vehicle driving assistance device 10 advances the process to step S745 to execute the coasting control, and then advances the process to step S795 to temporarily terminate the process of this routine.

[0182] As described above, when the coasting acceleration condition C6 (downhill gradient condition) is satisfied and the vehicle speed V is lower than the set vehicle speed V_S (predetermined traveling speed), the economic autonomous traveling control is terminated and the coasting control is executed.

[0183] Specifically, when the vehicle 100 is traveling on a downhill road with a gentle gradient and the vehicle speed V is less than the set vehicle speed V_S, the vehicle driving support device 10 executes the coasting control because the vehicle speed V increases even if the vehicle 100 is coasted.

[0184] On the other hand, when the determination in step S740 is "NO", the vehicle driving assistance device 10 advances the process to step S750 to execute the normal vehicle speed control, and then advances the process to step S795 to temporarily terminate the processing of this routine.

[0185] As described above, when the coasting acceleration condition C6 (downhill gradient condition) is satisfied and the vehicle speed V is equal to or higher than the set vehicle speed V_S (predetermined driving speed), the economic autonomous driving control is terminated and the normal vehicle speed control is executed.

[0186] Furthermore, after the determination in step S740 is "YES" and the coasting control is started in step S745, when the own vehicle speed V reaches the set vehicle speed V_S, the vehicle travel control is switched from the coasting control to the normal vehicle speed control.

[0187] As described above, the vehicle driving assistance device 10 is configured to terminate the economic autonomous driving control (autonomous driving control in the first driving mode) and execute the coasting control (autonomous driving control based on the power control in the first state) when the coasting acceleration condition C6 (first condition) is satisfied. Furthermore, the coasting acceleration condition C6 (first condition) is a condition that is easily satisfied when the vehicle 100 is traveling downhill. Furthermore, the coasting acceleration threshold G_T is set to the first coasting acceleration threshold G1 when the vehicle 100 is traveling in the hybrid drive mode (first drive mode), and to the second coasting acceleration threshold G2 when the vehicle 100 is traveling in the motor drive mode (second drive mode). The first coasting acceleration threshold G1 is a value smaller than the second coasting acceleration threshold G2. Therefore, the coasting acceleration condition C6 (first condition) is set to a condition that is more likely to be met when the own vehicle 100 is driven autonomously by the economic autonomous driving control in the hybrid driving mode (autonomous driving control in the first driving mode) than when the own vehicle 100 is driven autonomously by the economic autonomous driving control in the motor driving mode (autonomous driving control in the second driving mode).

[0188] When the vehicle 100 is traveling downhill, even if the vehicle 100 is autonomously traveling using coasting control, the vehicle speed V tends to increase, so there is no need to increase the vehicle speed V by autonomously traveling the vehicle 100 using optimal power running control. Therefore, when the vehicle 100 is traveling downhill, autonomously traveling using coasting control achieves a greater energy consumption reduction effect than autonomously traveling using optimal power running control. Furthermore, when autonomously traveling the vehicle 100 in hybrid drive mode using economic autonomous driving control, autonomously traveling the vehicle 100 without optimal power running control achieves a greater energy consumption reduction effect than autonomously traveling the vehicle 100 in motor drive mode using economic autonomous driving control.

[0189] According to the vehicle driving assistance device 10, the coasting acceleration condition C6 is a condition that is easily satisfied when the vehicle 100 is traveling downhill. That is, the coasting acceleration condition C6 is a condition that easily causes the vehicle 100 to discontinue economic autonomous driving control and execute coasting control when traveling downhill. Furthermore, the coasting acceleration condition C6 is set to a condition that is less likely to be satisfied when the vehicle 100 is autonomously traveling using economic autonomous driving control in motor drive mode than when the vehicle 100 is autonomously traveling using economic autonomous driving control in hybrid drive mode. That is, the coasting acceleration condition C6 is a condition that makes it difficult to discontinue economic autonomous driving control and execute coasting control when the vehicle 100 is autonomously traveling using economic autonomous driving control in motor drive mode. Therefore, a significant reduction in energy consumption can be achieved.

[0190] In addition, according to the vehicle driving assistance device 10, the own vehicle speed V is as follows Figure 9 is controlled as shown. Figure 9 In the example shown, until time t60, the vehicle 100 is traveling on a road with a road gradient θ of zero, i.e., a flat road, and optimal power running control is being executed. Consequently, the vehicle speed V gradually increases until time t60. Furthermore, the optimal power running acceleration Ga and the coasting acceleration Gd at this time are the first optimal power running acceleration Ga1 and the first coasting acceleration Gd1, respectively. The first optimal power running acceleration Ga1 is a positive value, while the first coasting acceleration Gd1 is a negative value.

[0191] Then, at time t60, the vehicle 100 starts traveling downhill. Figure 9 In the example shown, the road gradient θ decreases continuously from time t60 to time t62, and then reaches a constant value θ2 after time t62. Therefore, from time t60 to time t62, the optimal power running acceleration Ga and the coasting acceleration Gd gradually increase. In other words, the absolute value of the optimal power running acceleration Ga gradually increases. Meanwhile, the coasting acceleration Gd is negative until time t61, so its absolute value gradually decreases. After time t61, it becomes positive, so its absolute value gradually increases. Then, after time t62, the optimal power running acceleration Ga and the coasting acceleration Gd remain constant at the third optimal power running acceleration Ga3 and the third coasting acceleration Gd3, respectively.

[0192] exist Figure 9In the example shown, optimal power running control continues from time t60 to time t61. Furthermore, because the vehicle 100 is traveling downhill, its own vehicle speed V continues to increase at a relatively high rate. At time t61, coasting acceleration condition C6 is satisfied. At this point, since the own vehicle speed V is less than the set vehicle speed V_S, economic autonomous driving control ends and coasting control begins. As a result, the rate of increase in the own vehicle speed V decreases, but the own vehicle speed V continues to increase.

[0193] Then, at time t62, when the vehicle speed V reaches the set speed V_S, the coasting control ends and the normal speed control begins. Thus, after the vehicle speed V reaches the set speed V_S, the acceleration and deceleration of the vehicle 100 are controlled so as to be maintained at the set speed V_S.

[0194] For example, if the vehicle 100 is coasting down a hill, it may accelerate rather than decelerate, causing the vehicle speed V to become excessively high. Consequently, the vehicle speed V may not be maintained within the set vehicle speed range R_V or the preceding vehicle distance DF may not be maintained within the set preceding vehicle distance range R_DF under the economic autonomous driving control. In such a situation, it is undesirable to continue the economic autonomous driving control.

[0195] According to the vehicle driving assistance device 10 , the economic autonomous driving control is terminated when the coasting acceleration condition C6 is satisfied. Therefore, it is possible to prevent the economic autonomous driving control from being continued in a situation where the economic autonomous driving control is not desired.

[0196] In addition, when the determination result in step S735 is "No", the vehicle driving assistance device 10 proceeds to step S755. Figure 5 In step S505 of the routine shown, the processing is executed as described above, and then the processing of this routine is temporarily terminated.

[0197] If the vehicle driving assistance device 10 determines "No" in step S715, the process proceeds to step S760 to execute engine continuous operation control. The process then proceeds to step S795, temporarily terminating the processing of this routine. Engine continuous operation control is a mode in which the vehicle 100 is driven in engine drive mode. Engine drive mode is a mode in which the internal combustion engine 21 is continuously operated.

[0198] Furthermore, the vehicle driving assistance device 10 executes the Figure 10 Therefore, when a predetermined timing comes, the vehicle driving assistance device 10 starts Figure 10The process of the routine shown starts at step S1000, and the process proceeds to step S1005, where it is determined whether the internal combustion engine continuous operation condition C8 is satisfied.

[0199] Internal combustion engine continuous operation condition C8 is a condition that is satisfied when it is necessary to continue operating the internal combustion engine 21. For example, when the charge level of the power storage device 41 falls below a predetermined level (predetermined charge level), and the internal combustion engine 21 needs to be operated to charge the power storage device 41, the need to continue operating the internal combustion engine 21 arises.

[0200] When the determination in step S1005 is "NO", the vehicle driving support device 10 advances the process to step S1010 to determine whether the requested power P_REQ is equal to or greater than a predetermined requested power P_REQ_T.

[0201] If the determination in step S1010 is "YES," the vehicle driving assistance device 10 proceeds to step S1015, where the hybrid drive mode flag X_HV is set to "1" and the motor drive mode flag X_EV is set to "0." The device then proceeds to step S1095, temporarily terminating the present routine. In this case, the vehicle 100 is traveling in the hybrid drive mode.

[0202] On the other hand, if the determination in step S1010 is "No," the vehicle driving assistance device 10 proceeds to step S1020, where the hybrid drive mode flag X_HV is set to "0" and the motor drive mode flag X_EV is set to "1." The process then proceeds to step S1095, temporarily terminating the present routine. In this case, the vehicle 100 is traveling in the motor drive mode.

[0203] If the determination in step S1005 is "YES," the vehicle driving assistance device 10 proceeds to step S1025, where the hybrid drive mode flag X_HV is set to "0" and the motor drive mode flag X_EV is set to "0." The device then proceeds to step S1095, temporarily terminating the present routine. In this case, the vehicle 100 is traveling in the engine drive mode.

[0204] Furthermore, the vehicle driving assistance device 10 executes the Figure 11 Therefore, when a predetermined timing comes, the vehicle driving assistance device 10 starts Figure 11 The process of the routine shown starts at step S1100 , and the process proceeds to step S1105 , where it is determined whether or not the economical vehicle speed control is being executed.

[0205] If the determination in step S1105 is “YES”, the vehicle driving assistance device 10 proceeds to step S1110 to determine whether the value of the hybrid drive mode flag X_HV is “1”. In other words, the vehicle driving assistance device 10 determines whether the vehicle 100 is currently traveling in the hybrid drive mode.

[0206] When the determination in step S1110 is “YES”, the vehicle driving assistance device 10 advances the process to step S1115 to determine whether the economy level LV is the high economy level LV_H.

[0207] like Figure 1 As shown, the vehicle 100 is equipped with an economy level setting operator 73 such as an economy level setting button. The economy level setting operator 73 is electrically connected to the ECU 90. By operating the economy level setting operator 73, the driver can set the economy level LV (energy efficiency level) to one of the high economy level LV_H, the medium economy level LV_M, and the low economy level LV_L.

[0208] The economy level LV is a level requested by the driver as a level for improving the energy efficiency of the power unit 20 (energy efficiency improvement level). When the economy level LV is set to the high economy level LV_H, the driver has requested the maximum energy efficiency improvement level. When the economy level LV is set to the low economy level LV_L, the driver has requested the minimum energy efficiency improvement level. When the economy level LV is set to the medium economy level LV_M, the driver has requested an energy efficiency improvement level that is less than the maximum energy efficiency improvement level but greater than the minimum energy efficiency improvement level.

[0209] As described below, the vehicle driving assistance device 10 sets the set vehicle speed range R_V based on the economy level LV. In general, the higher the economy level LV, the larger the set vehicle speed range R_V and the set preceding vehicle distance range R_DF. In particular, in this example, when the vehicle 100 is traveling in hybrid drive mode, the set vehicle speed range R_V and the set preceding vehicle distance range R_DF can be changed by a setting operation performed by the driver of the vehicle 100.

[0210] When the determination in step S1115 is YES, the vehicle driving assistance device 10 advances the process to step S1120 to determine whether the rear detection normal condition C9 is satisfied.

[0211] The normal rear detection condition C9 is satisfied when the rear information detection device 52 functions normally and normally detects the rear detection information IR used to detect the following vehicle 300. Therefore, the normal rear detection condition C9 is not satisfied when the rear detection information IR used to detect the following vehicle 300 cannot be detected due to a malfunction of the rear information detection device 52 or other reasons. Alternatively, the normal rear detection condition C9 may not be satisfied when the own vehicle 100 is not equipped with the rear information detection device 52.

[0212] If the determination in step S1120 is "YES," the vehicle driving assistance device 10 proceeds to step S1125, sets the controlled vehicle speed range dV to the first vehicle speed range dV1, and then proceeds to step S1195, temporarily terminating the processing of this routine. The first vehicle speed range dV1 is set to a value greater than zero.

[0213] On the other hand, if the determination in step S1120 is "No," the vehicle driving assistance device 10 proceeds to step S1130, sets the controlled vehicle speed range dV to the second vehicle speed range dV2, and then proceeds to step S1195, temporarily terminating the processing of this routine. The second vehicle speed range dV2 is set to a value greater than zero and smaller than the first vehicle speed range dV1.

[0214] Like this, the vehicle driving assistance device 10 is configured so that, during the execution of the economical vehicle speed control (vehicle speed increase and decrease control), when the rear detection normal condition C9 is not satisfied (when the control range change condition that the subsequent vehicle detection device that detects the subsequent vehicle 300 has an abnormality is satisfied), the set vehicle speed range R_V is set to a smaller range than when the rear detection normal condition C9 is satisfied (when the control range change condition is not satisfied).

[0215] In other words, the vehicle driving assistance device 10 is configured so that when an abnormality occurs in the rear information detection device 52 (a subsequent vehicle detection device that detects the subsequent vehicle 300) while the own vehicle 100 is driving autonomously through the economic vehicle speed control in the hybrid driving mode (autonomous driving control in the first driving mode), the set vehicle speed range R_V (set control range) is set to a smaller range than when the rear information detection device 52 is normal.

[0216] If the vehicle 100 is autonomously traveling under economical speed control and a following vehicle 300 is present, if the vehicle speed V of the vehicle 100 increases or decreases excessively, the following vehicle 300 will significantly increase or decrease its speed, potentially disrupting the smooth flow of surrounding vehicles, including the following vehicle 300. Therefore, to maintain smooth flow of surrounding vehicles, it is desirable to autonomously travel the vehicle 100 under economical speed control while taking into account the presence of the following vehicle 300 when the following vehicle 300 is present. However, if the rear information detection device 52 experiences an abnormality or other reason and cannot detect the following vehicle 300, economical speed control cannot be executed while taking into account the presence of the following vehicle 300. Consequently, the vehicle 100 cannot autonomously travel under economical speed control in a manner that maintains smooth flow of surrounding vehicles.

[0217] According to the vehicle driving assistance device 10, when an abnormality occurs in the rear information detection device 52, the set vehicle speed range R_V is set to a smaller range than when the rear information detection device 52 is normal. This prevents excessive fluctuations in the own vehicle speed V. Therefore, even when the following vehicle 300 cannot be detected, the own vehicle 100 can be driven autonomously through economical speed control without disrupting the smooth flow of surrounding vehicles.

[0218] Furthermore, when the determination result in step S1115 is "NO", the vehicle driving assistance device 10 advances the process to step S1135 to determine whether the economy level LV is the middle economy level LV_M.

[0219] When the determination in step S1135 is YES, the vehicle driving assistance device 10 advances the process to step S1140 to set the controlled vehicle speed range dV to the second vehicle speed range dV2, and then advances the process to step S1195 to temporarily terminate the process of this routine.

[0220] On the other hand, if the determination in step S1135 is "No," the vehicle driving assistance device 10 proceeds to step S1145, sets the control vehicle speed range dV to the third vehicle speed range dV3, and then proceeds to step S1195, temporarily terminating the processing of this routine. The third vehicle speed range dV3 is set to a value greater than zero and smaller than the second vehicle speed range dV2.

[0221] Furthermore, when the determination in step S1110 is "NO", the vehicle driving assistance device 10 advances the process to step S1150 to determine whether the value of the motor drive mode flag X_EV is "1".

[0222] If the determination in step S1150 is "YES," the vehicle driving assistance device 10 proceeds to step S1155, where the control vehicle speed range dV is set to the fourth vehicle speed range dV4. The device then proceeds to step S1195, temporarily terminating the present routine. The fourth vehicle speed range dV4 is set to a value greater than zero and smaller than the third vehicle speed range dV3.

[0223] In this way, the vehicle driving assistance device 10 is configured to be able to perform economical vehicle speed control (vehicle speed increase and decrease control) in a hybrid driving mode (first driving mode) in which both the internal combustion engine 21 and the electric motor 22 or only the internal combustion engine 21 are operated to apply power to the own vehicle 100 to cause the own vehicle 100 to move, and in a motor driving mode (second driving mode) in which only the electric motor 22 is operated to apply power to the own vehicle 100 to cause the own vehicle 100 to move.

[0224] Furthermore, the set vehicle speed range R_V when executing the economical vehicle speed control in the motor drive mode (second drive mode) is set to a smaller range than when executing the economical vehicle speed control (vehicle speed increase / decrease control) in the hybrid drive mode (first drive mode).

[0225] Furthermore, the condition for reducing the controlled vehicle speed amplitude dV includes the condition of performing economical vehicle speed control (vehicle speed increase and decrease control) in the hybrid drive mode (first drive mode). The vehicle driving assistance device 10 is configured such that when performing economical vehicle speed control in the motor drive mode (second drive mode), the set vehicle speed range R_V is not changed even if the rear detection normal condition C9 does not meet (even if the control range change condition meets).

[0226] In other words, the vehicle driving assistance device 10 is configured such that, during the execution of the economical vehicle speed control in the motor drive mode (autonomous driving control in the second drive mode), even if an abnormality occurs in the rear information detection device 52 (a subsequent vehicle detection device that detects the subsequent vehicle 300), the control vehicle speed amplitude dV (the set control range) is not changed.

[0227] According to the vehicle driving assistance device 10, when the self-vehicle 100 is autonomously driven using economical speed control in motor drive mode, the set speed range R_V is set to a relatively small range. Therefore, if the rear information detection device 52 experiences an abnormality and cannot detect the following vehicle 300, even if the self-vehicle 100 continues to autonomously drive using economical speed control without changing the set speed range R_V, the self-vehicle speed V will not increase or decrease significantly, and the following vehicle 300 will not significantly increase or decrease its speed. Therefore, the possibility of obstructing the smooth flow of surrounding vehicles is minimized. Therefore, the self-vehicle 100 can be autonomously driven using economical speed control without changing the set speed range R_V, maintaining smooth flow of surrounding vehicles.

[0228] In addition, the vehicle driving assistance device 10 is configured so that, during the execution of the economical vehicle speed control, when the driving mode is a hybrid driving mode (a first driving mode that can use power other than power generated by the electricity of the storage device 41), the controlled vehicle speed amplitude dV (set control range) is set to a larger range than when it is a motor driving mode (a second driving mode that only uses power generated by the electricity of the storage device 41).

[0229] In addition, the vehicle driving assistance device 10 is configured to, when the rear detection normal condition C9 is satisfied (the control range change condition is not satisfied) while selectively executing idling control (power control in the first state) and optimal power operation control (power control in the second state) while executing economic vehicle speed control (vehicle speed increase and decrease control), when the own vehicle 100 is driven autonomously by the economic vehicle speed control in the hybrid drive mode (vehicle speed increase and decrease control in the first drive mode), the set vehicle speed range R_V is set to a larger range than when the own vehicle 100 is driven autonomously in the second drive mode by the economic vehicle speed control in the motor drive mode (vehicle speed increase and decrease control in the second drive mode).

[0230] When autonomous driving control is executed, that is, when the vehicle 100 is autonomously driven using economical vehicle speed control while selectively executing coasting control and optimal acceleration control, the energy consumption reduction effect generally increases when the set vehicle speed range R_V is set to a wider range when the vehicle 100 is autonomously driven in hybrid drive mode. However, when the vehicle 100 is autonomously driven in motor drive mode, even if the set vehicle speed range R_V is set to a wider range, the energy consumption reduction effect is not significantly increased, but the possibility of obstructing the smooth flow of surrounding vehicles increases.

[0231] According to the vehicle driving assistance device 10, when the vehicle 100 autonomously drives through economical speed control while selectively executing coasting control and optimal power running control, and the rear detection normal condition C9 is satisfied, the set vehicle speed range R_V is set to a wider range when the drive mode is the hybrid drive mode than when the drive mode is the motor drive mode. This allows for a consistent energy consumption reduction effect according to the drive mode while suppressing obstruction to smooth traffic flow of surrounding vehicles.

[0232] On the other hand, if the vehicle driving assistance device 10 determines "No" in step S1150, the process proceeds to step S1160, where the controlled vehicle speed width dV is set to zero. The process then proceeds to step S1195, temporarily terminating the present routine. In this case, the drive mode is neither hybrid drive mode nor motor drive mode, so engine continuous operation control is executed as previously described.

[0233] Furthermore, if the vehicle driving assistance device 10 determines "No" in step S1105, the process proceeds to step S1160, where the controlled vehicle speed width dV is set to zero. The process then proceeds to step S1195, temporarily terminating the present routine. In this case, if there is no preceding vehicle 200, normal vehicle speed control is executed.

[0234] Furthermore, the vehicle driving assistance device 10 executes the Figure 12 Therefore, when a predetermined timing comes, the vehicle driving assistance device 10 starts Figure 12 The routine shown starts processing at step S1200 and proceeds to step S1205 to determine whether the economic autonomous driving condition C3 is satisfied. That is, the vehicle driving assistance device 10 determines whether the economic autonomous driving control is being executed.

[0235] If the determination in step S1205 is “YES”, the vehicle driving assistance device 10 proceeds to step S1210 to determine whether the value of the hybrid drive mode flag X_HV is “1”. That is, the vehicle driving assistance device 10 determines whether the drive mode is the hybrid drive mode.

[0236] If the vehicle driving assistance device 10 determines "YES" in step S1210, the process proceeds to step S1215, where the optimal power running power P_OPT is set based on the vehicle's own speed V. The process then proceeds to step S1295, temporarily terminating the present routine. In this case, the economic autonomous driving control is executed based on the optimal power running power P_OPT set in step S1215.

[0237] On the other hand, if the determination in step S1210 is “No”, the vehicle driving assistance device 10 proceeds to step S1220 to determine whether the value of the motor driving mode flag X_EV is “1”. In other words, the vehicle driving assistance device 10 determines whether the driving mode is the motor driving mode.

[0238] If the vehicle driving assistance device 10 determines "YES" in step S1220, the process proceeds to step S1225, where the optimal power running power P_OPT is set based on the vehicle's own speed V. The process then proceeds to step S1295, temporarily terminating the present routine. In this case, economic autonomous driving control is executed based on the optimal power running power P_OPT set in step S1225.

[0239] On the other hand, if the vehicle driving assistance device 10 determines "No" in step S1220, the process proceeds to step S1230, where the optimal power operating power P_OPT is set to zero. The process then proceeds to step S1295, temporarily terminating the present routine. In this case, the drive mode is neither the hybrid drive mode nor the motor drive mode, so the engine continuous operation control is executed as previously described.

[0240] If the vehicle driving assistance device 10 determines "No" in step S1205, the process proceeds to step S1230, where the optimal power running power P_OPT is set to zero. The process then proceeds to step S1295, temporarily terminating the present routine. In this case, the economic autonomous driving condition C3 is not met, so normal autonomous driving control is executed.

[0241] Furthermore, the vehicle driving assistance device 10 executes the Figure 13 Therefore, when a predetermined timing comes, the vehicle driving assistance device 10 starts Figure 13 The routine shown starts processing at step S1300 and proceeds to step S1305 to determine whether the economic autonomous driving condition C3 is satisfied. That is, the vehicle driving assistance device 10 determines whether the economic autonomous driving control is currently being executed.

[0242] If the determination in step S1305 is “YES”, the vehicle driving assistance device 10 proceeds to step S1310 to determine whether the value of the hybrid drive mode flag X_HV is “1”. In other words, the vehicle driving assistance device 10 determines whether the vehicle 100 is currently traveling in the hybrid drive mode.

[0243] When the determination in step S1310 is YES, the vehicle driving assistance device 10 advances the process to step S1315 to determine whether the rear detection normal condition C9 is satisfied.

[0244] If the determination in step S1315 is "YES," the vehicle driving assistance device 10 proceeds to step S1320, where the control inter-vehicle distance width dD is set to the first inter-vehicle distance width dD1. The process then proceeds to step S1395, temporarily terminating the present routine. The first inter-vehicle distance width dD1 is set to a value greater than zero. In this case, when executing economic inter-vehicle distance control, economic inter-vehicle distance control is executed based on the set vehicle speed range R_V set based on the first inter-vehicle distance width dD1.

[0245] On the other hand, if the determination in step S1315 is "No," the vehicle driving assistance device 10 proceeds to step S1325, where the control inter-vehicle distance width dD is set to the second inter-vehicle distance width dD2. The process then proceeds to step S1195, temporarily terminating the present routine. The second inter-vehicle distance width dD2 is set to a value greater than zero and smaller than the first inter-vehicle distance width dD1. In this case, when executing economic inter-vehicle distance control, economic inter-vehicle distance control is executed based on the set vehicle speed range R_V, which is set based on the second inter-vehicle distance width dD2, which is smaller than the first inter-vehicle distance width dD1.

[0246] Like this, the vehicle driving assistance device 10 is configured so that, during the execution of the economical vehicle distance control (vehicle distance increase and decrease control), when the rear detection normal condition C9 is not satisfied (when the control range change condition that the subsequent vehicle detection device that detects the subsequent vehicle 300 has an abnormality is satisfied), the leading vehicle distance range R_DF is set to a smaller range than when the rear detection normal condition C9 is satisfied (when the control range change condition is not satisfied).

[0247] In other words, the vehicle driving assistance device 10 is configured so that, when an abnormality occurs in the rear information detection device 52 (a subsequent vehicle detection device that detects the subsequent vehicle 300) while the own vehicle 100 is driving autonomously through the economical vehicle distance control in the hybrid driving mode (autonomous driving control in the first driving mode), the preceding vehicle distance range R_DF (set control range) is set to a smaller range than when the rear information detection device 52 is normal.

[0248] If the following vehicle 300 is present while the own vehicle 100 is autonomously traveling using economical distance control, and the preceding vehicle distance DF increases or decreases excessively, the following vehicle 300 may significantly increase or decrease its speed, potentially disrupting the smooth flow of surrounding vehicles, including the following vehicle 300. Therefore, to maintain smooth flow of surrounding vehicles, it is desirable to autonomously travel the own vehicle 100 using economical distance control while the following vehicle 300 is present. However, if the rear information detection device 52 experiences an abnormality or is unable to detect the following vehicle 300, economical distance control cannot be executed while taking into account the presence of the following vehicle 300. Consequently, autonomous travel of the own vehicle 100 using economical distance control cannot be performed in a manner that maintains smooth flow of surrounding vehicles.

[0249] According to the vehicle driving assistance device 10, if an abnormality occurs in the rear information detection device 52, the preceding vehicle distance range R_DF is set to a smaller range than when the rear information detection device 52 is normal. This prevents excessive increases or decreases in the preceding vehicle distance DF. Therefore, even if an abnormality occurs in the rear information detection device 52, the vehicle 100 can be driven autonomously using economical inter-vehicle distance control without disrupting the smooth flow of surrounding vehicles.

[0250] If the determination in step S1310 is "No," the vehicle driving assistance device 10 proceeds to step S1330 to determine whether the value of the motor drive mode flag X_EV is "1." In other words, the vehicle driving assistance device 10 determines whether the vehicle 100 is currently traveling in the motor drive mode.

[0251] If the determination in step S1330 is "YES," the vehicle driving assistance device 10 proceeds to step S1335, where the control inter-vehicle distance width dD is set to the third inter-vehicle distance width dD3. The process then proceeds to step S1395, temporarily terminating the present routine. The third inter-vehicle distance width dD3 is set to a value greater than zero and smaller than the second inter-vehicle distance width dD2. In this case, when executing economic inter-vehicle distance control, economic inter-vehicle distance control is executed based on the set vehicle speed range R_V, which is set based on the third inter-vehicle distance width dD3, which is smaller than the second inter-vehicle distance width dD2.

[0252] In this way, the vehicle driving assistance device 10 is configured to be able to perform economical vehicle distance control (vehicle distance increase and decrease control) in a hybrid drive mode (first drive mode) in which both the internal combustion engine 21 and the electric motor 22 or only the internal combustion engine 21 is operated to apply power to the own vehicle 100 to cause the own vehicle 100 to move, and in a motor drive mode (second drive mode) in which only the electric motor 22 is operated to apply power to the own vehicle 100 to cause the own vehicle 100 to move.

[0253] Furthermore, the set preceding vehicle distance range R_DF when executing the economical inter-vehicle distance control in the motor drive mode (second drive mode) is set to a smaller range than when executing the economical inter-vehicle distance control (inter-vehicle distance increase / decrease control) in the hybrid drive mode (first drive mode).

[0254] Furthermore, the condition for reducing the controlled vehicle distance amplitude dD includes the condition of executing economical vehicle distance control (vehicle distance increase and decrease control) in the hybrid drive mode (first drive mode). The vehicle driving assistance device 10 is configured such that when executing economical vehicle distance control (vehicle distance increase and decrease control) in the motor drive mode (second drive mode), even if the rear detection normal condition C9 does not meet (even if the control range change condition meets), the set leading vehicle distance range R_DF (set vehicle distance range) is not changed.

[0255] In other words, the vehicle driving assistance device 10 is configured such that, during the execution of the economical vehicle distance control in the motor drive mode (second drive mode), even if an abnormality occurs in the rear information detection device 52 (a subsequent vehicle detection device that detects the subsequent vehicle 300), the controlled vehicle distance amplitude dD (the set control range) is not changed.

[0256] According to the vehicle driving assistance device 10, when the self-vehicle 100 is autonomously driven using economical inter-vehicle distance control in motor drive mode, the preceding vehicle distance range R_DF is set to a relatively small range. Therefore, if the rear information detection device 52 experiences an abnormality and cannot detect the following vehicle 300, even if the self-vehicle 100 continues autonomously driving using economical inter-vehicle distance control without changing the preceding vehicle distance range R_DF, the preceding vehicle distance DF will not increase or decrease significantly, and the following vehicle 300 will not significantly increase or decrease its speed. Therefore, the possibility of disrupting the smooth flow of surrounding vehicles is minimized. Therefore, the self-vehicle 100 can be autonomously driven using economical inter-vehicle distance control without changing the preceding vehicle distance range R_DF, maintaining the smooth flow of surrounding vehicles.

[0257] In addition, the vehicle driving assistance device 10 is configured so that, during the execution of the economical vehicle distance control, when the driving mode is a hybrid driving mode (a first driving mode that can use power other than power generated by the electricity of the storage device 41), the controlled vehicle distance amplitude dD (set control range) is set to a larger range than when it is a motor driving mode (a second driving mode that only uses power generated by the electricity of the storage device 41).

[0258] In addition, the vehicle driving assistance device 10 is configured to, when the rear detection normal condition C9 is satisfied (the control range change condition is not satisfied) while selectively executing coasting control (power control in the first state) and optimal power operation control (power control in the second state) while executing economic vehicle distance control (vehicle distance increase and decrease control), when the own vehicle 100 is driven autonomously by the economic vehicle distance control in the hybrid drive mode (vehicle distance increase and decrease control in the first drive mode), the set leading vehicle distance range R_DF (set vehicle distance range) is set to a larger range than when the own vehicle 100 is driven autonomously in the second drive mode by the economic vehicle distance control in the motor drive mode (vehicle distance increase and decrease control in the second drive mode).

[0259] When autonomous driving control is executed, that is, when the vehicle 100 autonomously drives by selectively executing coasting control and optimal acceleration control while using economical inter-vehicle distance control, if the preceding vehicle distance range R_DF is set to a larger range when the vehicle 100 autonomously drives in hybrid drive mode, the energy consumption reduction effect generally increases. However, when the vehicle 100 autonomously drives in motor drive mode, even if the preceding vehicle distance range R_DF is set to a larger range, the energy consumption reduction effect is not significantly increased, but the possibility of obstructing the smooth flow of surrounding vehicles increases.

[0260] According to the vehicle driving assistance device 10, when the vehicle 100 autonomously drives through economical inter-vehicle distance control while selectively executing coasting control and optimal power running control, and a normal rear detection condition C9 is satisfied, the preceding vehicle distance range R_DF is set to a larger range when the drive mode is the hybrid drive mode than when the drive mode is the motor drive mode. This allows for a consistent energy consumption reduction effect according to the drive mode while preventing obstruction to the smooth flow of surrounding vehicles.

[0261] On the other hand, if the vehicle driving assistance device 10 determines "No" in step S1330, the process proceeds to step S1340, where the controlled inter-vehicle distance width dD is set to zero. The process then proceeds to step S1395, temporarily terminating the present routine. In this case, the drive mode is neither hybrid drive mode nor motor drive mode, so engine continuous operation control is executed as previously described.

[0262] Furthermore, when the determination in step S1305 is "No", the vehicle driving assistance device 10 also advances the processing to step S1340 to set the controlled inter-vehicle distance width dD to zero, and then advances the processing to step S1195 to temporarily terminate the processing of this routine.

[0263] In addition, the present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention.

[0264] For example, the vehicle driving assistance device 10 may be configured to execute the economic vehicle speed control when the own vehicle speed V increases and reaches an upper limit vehicle speed V_U described later during execution of the economic vehicle distance control.

[0265] In addition, in Figure 3A As shown, when there is a following vehicle 300, the vehicle driving assistance device 10 may also be configured to execute optimal power running control and accelerate the host vehicle 100 when the following vehicle distance DR becomes less than the predetermined following vehicle distance DR_T, even if the preceding vehicle distance DF is less than the upper limit preceding vehicle distance DF_U during execution of the economical inter-vehicle distance control. In this case, after starting the optimal power running control, the vehicle driving assistance device 10 continues the optimal power running control until the preceding vehicle distance DF reaches the lower limit preceding vehicle distance DF_L, even if the following vehicle distance DR becomes greater than the predetermined following vehicle distance DR_T.

[0266] In addition, when there is a following vehicle 300, the vehicle driving assistance device 10 can also be configured to consider the difference between the own vehicle speed V and the driving speed of the following vehicle 300 during the execution of the economical vehicle distance control, so as to determine the timing of starting the optimal power operation control in a manner that prevents the own vehicle 100 from getting too close to the following vehicle 300.

[0267] In addition, in Figure 3BAs shown, when there is a following vehicle 300 as another vehicle surrounding the own vehicle 100, the vehicle driving assistance device 10 may be configured to execute optimal power running control and accelerate the own vehicle 100 when the distance between the own vehicle 100 and the following vehicle 300 (the following vehicle distance DR) becomes less than a predetermined distance (the predetermined following vehicle distance DR_T) even if the own vehicle speed V exceeds the lower speed limit V_L during execution of the economical speed control. In this case, after starting the optimal power running control, the vehicle driving assistance device 10 continues the optimal power running control until the own vehicle speed V reaches the upper speed limit V_U, even if the following vehicle distance DR becomes greater than the predetermined following vehicle distance DR_T.

[0268] In addition, when there is a following vehicle 300, the vehicle driving assistance device 10 can also be configured to consider the difference between the own vehicle speed V and the driving speed of the following vehicle 300 during the execution of economical vehicle speed control, so as to determine the timing of starting optimal power operation control in a manner that prevents the own vehicle 100 from getting too close to the following vehicle 300. Description of Reference Numerals

[0269] 10…Vehicle driving assistance device, 20…Power unit, 41…Power storage device, 52…Rear information detection device, 90…ECU, 100…Own vehicle, 200…Front vehicle, 300…Following vehicle

Claims

1. A vehicle driving assistance device comprising a control device configured to execute autonomous driving control for causing a vehicle to autonomously drive in a first driving mode, wherein in the first driving mode, power control is selectively executed in a first state in which power generation loss in a power unit or power transmission loss from the power unit to drive wheels is reduced, and in a second state in which the power unit is mechanically or electrically connected to the drive wheels to apply power to the drive wheels, thereby increasing or decreasing a control value of the vehicle within a set control range, wherein: The control device is configured to, during execution of the autonomous driving control in the first driving mode, set the set control range to a larger range when the driving mode is a first driving mode in which power other than power generated by the electric power of the storage device can be used, compared to a second driving mode in which the driving mode only uses power generated by the electric power.

2. The vehicle driving assistance device according to claim 1, wherein: When the own vehicle is autonomously traveling by the autonomous traveling control in the first drive mode, the set control range can be changed by a setting operation performed by a driver of the own vehicle.

3. The vehicle driving assistance device according to claim 1, wherein: The control device is configured to set the set control range to a smaller range when an abnormality occurs in a subsequent vehicle detection device that detects a subsequent vehicle when the own vehicle is driving autonomously through the autonomous driving control in the first driving mode, compared to a case where the subsequent vehicle detection device is normal.

4. The vehicle driving assistance device according to claim 3, wherein: The control device is configured to be capable of executing the autonomous travel control in a second travel mode in which the control value is maintained at a set control value, The control device is configured to switch the mode of the autonomous driving control from the first driving mode to the second driving mode when, during the execution of the autonomous driving control in the first driving mode, the subsequent vehicle detection device is normal, detects the subsequent vehicle, and the distance between the subsequent vehicle and the own vehicle is less than a specified distance or the time required for the own vehicle to travel the distance between the subsequent vehicle and the own vehicle is less than a specified time, and this driving mode switching condition is met.

5. The vehicle driving assistance device according to claim 3 or 4, wherein: The set control range when the autonomous travel control is executed in the second drive mode is set to a smaller range than when the autonomous travel control is executed in the first drive mode. The control device is configured not to change the set control range even if an abnormality occurs in the following vehicle detection device during execution of the autonomous travel control in the second drive mode.

6. The vehicle driving assistance device according to claim 1, wherein: The control device is configured to, when a first condition is satisfied, suspend the autonomous travel control in the first travel mode and execute the autonomous travel control by the power control in the first state. The first condition is set to a condition that is easily satisfied when the own vehicle is traveling on a downhill road, and is more likely to be satisfied when the own vehicle is autonomously traveling by the autonomous traveling control in the first driving mode than when the own vehicle is autonomously traveling by the autonomous traveling control in the second driving mode.

7. The vehicle driving assistance device according to claim 1, wherein: The control device is configured to be capable of executing the autonomous driving control in a constant speed mode for maintaining the vehicle speed of the own vehicle at a set vehicle speed. The control device is configured to, when a second condition is satisfied, terminate the autonomous driving control in the first driving mode and execute the autonomous driving control in the constant speed mode. The second condition is set to a condition that is easily satisfied when the own vehicle is traveling on an uphill road or when the own vehicle is traveling at a speed greater than a specified speed, and is more easily satisfied when the own vehicle is autonomously traveling by the autonomous driving control in the first driving mode than when the own vehicle is autonomously traveling by the autonomous driving control in the second driving mode.

8. A vehicle driving assistance method, comprising: executing autonomous driving control for causing a vehicle to autonomously drive in a first driving mode, wherein in the first driving mode, power control is selectively executed in a first state in which power generation loss in a power unit or power transmission loss from the power unit to drive wheels is reduced, and in a second state in which the power unit is mechanically or electrically connected to the drive wheels to apply power to the drive wheels, so as to increase or decrease a control value of the vehicle within a set control range, wherein: The vehicle driving assistance method includes the following steps: in the execution of the autonomous driving control in the first driving mode, when the driving mode is a first driving mode in which power other than power generated by the electricity of the storage device can be used, the set control range is set to a larger range than when the driving mode is a second driving mode in which only power generated by the electricity is used.

9. A vehicle driving assistance program that performs autonomous driving control for causing a vehicle to autonomously drive in a first driving mode, wherein in the first driving mode, power control is selectively performed in a first state in which power generation loss in a power unit or power transmission loss from the power unit to drive wheels is reduced, and in a second state in which the power unit is mechanically or electrically connected to the drive wheels to apply power to the drive wheels, so as to increase or decrease a control value of the vehicle within a set control range, wherein: The vehicle driving assistance program is configured to, during execution of the autonomous driving control in the first driving mode, set the set control range to a larger range when the driving mode is a first driving mode in which a power other than the power generated by the electric power of the storage device is used, as compared to a second driving mode in which the driving mode only uses the power generated by the electric power.

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