JP7610178B2 - Vehicle Driving Assistance Device - Google Patents

Description

The present invention relates to a vehicle driving assistance device.

There is a known vehicle driving assistance device that performs automatic acceleration/deceleration control to automatically accelerate and decelerate the host vehicle so that the host vehicle follows the preceding vehicle when a preceding vehicle is traveling ahead of the host vehicle, and performs automatic acceleration/deceleration control to automatically accelerate and decelerate the host vehicle so that the host vehicle travels at a preset vehicle speed (set vehicle speed) when there is no preceding vehicle traveling ahead of the host vehicle (see, for example, Patent Document 1).

JP 2007-168788 A

For example, when the vehicle is traveling on a main lane of a highway and automatic acceleration/deceleration control is being performed, the vehicle travels at a speed equal to that of the preceding vehicle if there is a preceding vehicle, and travels at a set speed if there is no preceding vehicle. Therefore, the vehicle speed when the vehicle approaches the exit road of the highway is either equal to that of the preceding vehicle or is the set speed. For this reason, the driver must brake the vehicle relatively strongly when the vehicle enters the exit road. This results in a large loss of energy in the vehicle, and as a result, the energy consumption of the vehicle increases. In particular, when the driver wishes to drive the vehicle in a so-called eco mode to keep the energy consumption of the vehicle low, it is desirable to avoid driving the vehicle in a way that increases the energy consumption of the vehicle.

The object of the present invention is to provide a vehicle driving assistance device that can suppress the increase in the energy consumption of the vehicle caused by executing automatic acceleration/deceleration control.

The vehicle driving assistance device according to the present invention is a device that executes automatic acceleration/deceleration control for automatically accelerating and decelerating the host vehicle so that a forward vehicle distance, which is a distance between the host vehicle and a preceding vehicle traveling in front of the host vehicle on a lane in which the host vehicle is traveling, is maintained at a set forward vehicle distance. The vehicle driving assistance device according to the present invention is configured to interrupt the automatic acceleration/deceleration control and coast the host vehicle when the host vehicle is traveling on a highway during execution of the automatic acceleration/deceleration control, and when a branch road that branches off from a main road of the highway exists ahead of the host vehicle and is a point where the host vehicle is predicted to decelerate, and when the host vehicle is traveling on one of a plurality of lanes on the main road on which the branch road is located, and when the distance to the branch road becomes equal to or shorter than a predetermined distance, a request for the host vehicle to travel in an eco mode is made.

If automatic acceleration/deceleration control is executed until the host vehicle reaches a branching road on a highway where the host vehicle decelerates, when the host vehicle reaches the branching road on the highway , the host vehicle's speed is controlled so that the host vehicle follows the vehicle ahead , so that the host vehicle's speed is relatively high when the host vehicle reaches the branching road on the highway, and it becomes necessary to brake the host vehicle relatively strongly, resulting in large energy consumption by the host vehicle.

According to the present invention, when the distance to the branch road of the expressway, where the host vehicle is predicted to decelerate, is less than a predetermined distance, if the host vehicle is requested to run in the eco mode, the automatic acceleration/deceleration control is interrupted and the host vehicle is coasted. Therefore, when the host vehicle reaches the branch road of the expressway , the vehicle speed is relatively low, so there is no need to brake the host vehicle heavily. Therefore, it is possible to suppress an increase in the energy consumption of the host vehicle when the host vehicle is requested to run in the eco mode.

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

FIG. 1 is a diagram showing a vehicle driving assistance device according to an embodiment of the present invention and a vehicle (host vehicle) on which the vehicle driving assistance device is mounted. FIG. 2 is a diagram showing the forward inter-vehicle distance and the rear inter-vehicle distance, etc. FIG. 3 is a diagram showing a branch road of an expressway. FIG. 4 is a time chart showing changes in vehicle speed and the like when the vehicle driving assistance device according to the embodiment of the present invention executes automatic acceleration/deceleration control and the like. FIG. 5 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention.

Hereinafter, a vehicle driving assistance device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a vehicle driving assistance device 10 according to an embodiment of the present invention. The vehicle driving assistance device 10 is mounted on a host vehicle 100.

<ECU>
The vehicle driving assistance device 10 includes an ECU 90. ECU is an abbreviation for electronic control unit. The ECU 90 includes a microcomputer as a main component. The microcomputer includes a CPU, ROM, RAM, non-volatile memory, and an interface. The CPU executes instructions, programs, or routines stored in the ROM to realize various functions.

<Drive device, etc.>
The host vehicle 100 is equipped with a drive device 21 and a braking device 22 .

<Drive unit>
The drive device 21 is a device that outputs a drive force provided to the host vehicle 100 to drive the host vehicle 100, and is, for example, an internal combustion engine, a motor, etc. The drive device 21 is electrically connected to the ECU 90. The ECU 90 can control the drive force output from the drive device 21 by controlling the operation of the drive device 21.

<Braking device>
The braking device 22 is a device, such as a brake device, that outputs a braking force applied to the host vehicle 100 in order to brake the host vehicle 100. The braking device 22 is electrically connected to the ECU 90. The ECU 90 can control the braking force output from the braking device 22 by controlling the operation of the braking device 22.

<Sensors, etc.>
Furthermore, the vehicle 100 is equipped with an accelerator pedal 31, an accelerator pedal operation amount sensor 32, a brake pedal 33, a brake pedal operation amount sensor 34, an automatic acceleration/deceleration operator 41, an eco-driving operator 42, a front/rear information detection device 43, a vehicle speed detection device 44, and a road information acquisition device 50.

<Accelerator pedal operation amount sensor>
The accelerator pedal operation amount sensor 32 is electrically connected to the ECU 90. The accelerator pedal operation amount sensor 32 detects the operation amount of the accelerator pedal 31 and transmits information on the detected operation amount to the ECU 90. The ECU 90 obtains the operation amount of the accelerator pedal 31 as the accelerator pedal operation amount AP based on that information. The ECU 90 obtains the requested driving force Pd_req by calculation from the accelerator pedal operation amount AP and the vehicle speed V0 of the host vehicle 100. The requested driving force Pd_req is the driving force that the drive device 21 is required to output.

<Brake pedal operation amount sensor>
The brake pedal operation amount sensor 34 is electrically connected to the ECU 90. The brake pedal operation amount sensor 34 detects the operation amount of the brake pedal 33 and transmits information on the detected operation amount to the ECU 90. The ECU 90 obtains the operation amount of the brake pedal 33 as a brake pedal operation amount BP based on the information. The ECU 90 obtains a required braking force Pb_req from the brake pedal operation amount BP by calculation. The required braking force Pb_req is a braking force that the braking device 22 is required to output.

<Automatic acceleration/deceleration controller>
The automatic acceleration/deceleration operation device 41 is a device operated by the driver of the vehicle 100, and is composed of, for example, switches and buttons. These switches and buttons are provided, for example, on the steering wheel of the vehicle 100. Alternatively, it may be provided on a lever attached to the steering column of the vehicle 100 .

In this example, the automatic acceleration/deceleration operation device 41 includes an automatic acceleration/deceleration selection switch, a vehicle speed setting switch, a vehicle speed increase button, a vehicle speed decrease button, and a vehicle distance setting button. The automatic acceleration/deceleration operation device 41 is electrically connected to the ECU 90.

When the driver operates the automatic acceleration/deceleration selection switch when the automatic acceleration/deceleration control described below is not being executed, a signal is sent from the automatic acceleration/deceleration operation device 41 to the ECU 90. When the ECU 90 receives this signal, it determines that the driver is requesting that automatic acceleration/deceleration control be executed. On the other hand, when the driver operates the automatic acceleration/deceleration selection switch when automatic acceleration/deceleration control is being executed, a signal is sent from the automatic acceleration/deceleration operation device 41 to the ECU 90. When the ECU 90 receives this signal, it determines that the driver is requesting that automatic acceleration/deceleration control be terminated.

In addition, when the driver operates the vehicle speed setting switch while automatic acceleration/deceleration control is being performed, a signal is sent from the automatic acceleration/deceleration operation device 41 to the ECU 90. When the ECU 90 receives this signal, it sets the vehicle speed V0 of the vehicle 100 at that time as the set vehicle speed Vset for the automatic acceleration/deceleration control.

In addition, when the driver operates the vehicle speed increase button while automatic acceleration/deceleration control is being executed, a signal is sent from the automatic acceleration/deceleration operation device 41 to the ECU 90. When the ECU 90 receives this signal, it increases the set vehicle speed Vset. On the other hand, when the driver operates the vehicle speed decrease button while automatic acceleration/deceleration control is being executed, a signal is sent from the automatic acceleration/deceleration operation device 41 to the ECU 90. When the ECU 90 receives this signal, it decreases the set vehicle speed Vset.

In addition, when the driver operates the following distance setting button while automatic acceleration/deceleration control is being performed, a signal is sent from the automatic acceleration/deceleration operation device 41 to the ECU 90. This signal is a signal (required following distance signal) that indicates the distance (forward following distance D1) that the driver requests between the vehicle 100 and the preceding vehicle 101 in automatic acceleration/deceleration control by operating the following distance setting button. In this example, the driver can select one of a long distance, a medium distance, and a short distance as the forward following distance D1 by operating the following distance setting button.

As shown in FIG. 2, the forward vehicle distance D1 is the distance between the host vehicle 100 and the preceding vehicle 101. In this example, the preceding vehicle 101 is a vehicle traveling ahead of the host vehicle 100 in the lane in which the host vehicle 100 is traveling (host lane LN0), and whose distance from the host vehicle 100 (forward vehicle distance D1) is less than or equal to a predetermined preceding vehicle judgment distance D1th.

When the ECU 90 receives the required vehicle distance signal, it sets the distance indicated by the signal as the set vehicle distance ahead D1set. The specified preceding vehicle determination distance D1th is set to be longer than the set vehicle distance ahead D1set.

<Eco driving operation device>
The eco-driving operation device 42 is a device operated by the driver of the vehicle 100, and is composed of, for example, switches, buttons, etc. These switches, buttons, etc. are provided, for example, on the steering wheel of the vehicle 100, or on a lever attached to the steering column of the vehicle 100.

When the eco-driving operation device 42 is operated while it is in the off position, it changes to the on position. When the eco-driving operation device 42 is operated to the on position, it transmits a signal to the ECU 90. When the ECU 90 receives the signal, it determines that the driver has requested that the vehicle 100 be driven in eco mode. When the ECU 90 determines that the driver has requested that the vehicle 100 be driven in eco mode, it determines that the eco-driving condition Ceco is satisfied.

On the other hand, when the eco-driving operation device 42 is operated while it is in the on position, it is put into the off position. When the eco-driving operation device 42 is operated into the off position, it transmits a signal to the ECU 90. When the ECU 90 receives the signal, it determines that the driver has not requested that the vehicle 100 be driven in eco mode. In other words, the ECU 90 determines that the driver has requested that the vehicle 100 be driven in normal mode. When the ECU 90 determines that the driver has not requested that the vehicle 100 be driven in eco mode, it determines that the eco-driving condition Ceco is not satisfied.

The running of the vehicle 100 in the eco mode is the running of the vehicle 100 in which the amount of energy consumed for running the vehicle 100 is as small as possible. For example, when the power output from an internal combustion engine is used as the energy for running the vehicle 100, the running of the vehicle 100 in the eco mode is the running of the vehicle 100 in which the fuel efficiency is as high as possible, and when the power output from a motor is used as the energy for running the vehicle 100, the running of the vehicle 100 in the eco mode is the running of the vehicle 100 in which the electricity efficiency is as high as possible.

<Front and rear information detection device>
The front-rear information detection device 43 is a device that detects information in front of and behind the host vehicle 100. The front-rear information detection device 43 is, for example, a camera, a radar sensor (such as a millimeter wave radar), an ultrasonic sensor (clearance sonar), a laser radar (LiDAR), or the like.

The front-rear information detection device 43 is electrically connected to the ECU 90. The front-rear information detection device 43 transmits information ahead of the host vehicle 100 (front information) and information behind the host vehicle 100 (rear information) to the ECU 90. The ECU 90 can obtain the distance between the preceding vehicle 101 and the host vehicle 100 (forward inter-vehicle distance D1) and the vehicle speed V1 of the preceding vehicle 101 from the forward information. The ECU 90 can also obtain the distance between the following vehicle 102 and the host vehicle 100 (rear inter-vehicle distance D2) and the vehicle speed V2 of the following vehicle 102 from the rear information.

As shown in FIG. 2, the rear vehicle distance D2 is the distance between the host vehicle 100 and the following vehicle 102. In this example, the following vehicle 102 is a vehicle traveling behind the host vehicle 100 in the lane in which the host vehicle 100 is traveling (host lane LN0), and whose distance from the host vehicle 100 (rear vehicle distance D2) is less than or equal to a predetermined following vehicle judgment distance D2th.

<Vehicle speed detection device>
The vehicle speed detection device 44 is a device that detects the vehicle speed V0 of the host vehicle 100, and is, for example, a wheel speed sensor. The vehicle speed detection device 44 is electrically connected to the ECU 90. The vehicle speed detection device 44 detects the vehicle speed V0 of the host vehicle 100, and transmits information on the vehicle speed V0 to the ECU 90. The ECU 90 can obtain the vehicle speed V0 based on the information.

<Road information acquisition device>
The road information acquisition device 50 is a device that acquires information about the road on which the vehicle 100 is currently traveling, and in this example, includes a GPS device 51 , a database 52 and a receiving device 53 .

<GPS device>
The GPS device 51 is electrically connected to the ECU 90. The GPS device 51 receives a GPS signal and transmits the received GPS signal to the ECU 90. The ECU 90 can obtain the current position of the host vehicle 100 based on the GPS signal.

<Database>
Map data Dmap is stored in the database 52. The vehicle driving support device 10 may be configured to wirelessly acquire the map data Dmap from a database external to the host vehicle 100.

The database 52 is electrically connected to the ECU 90. The ECU 90 can compare the current position of the vehicle 100 with the map data Dmap and obtain information about the road on which the vehicle 100 is currently traveling (road information Iroad).

The ECU 90 can determine the type of road on which the vehicle 100 is traveling (for example, whether the road on which the vehicle 100 is traveling is a general road or an expressway) based on the road information Iroad.

In addition, as shown in FIG. 2, when the vehicle 100 is traveling on a road with multiple lanes LN1, LN2, and LN3, the ECU 90 can identify which lane the vehicle 100 is traveling in based on the road information Iroad and the current position of the vehicle 100. In the example shown in FIG. 2, the ECU 90 can identify the lane the vehicle 100 is traveling in as lane LN1 based on the road information Iroad and the current position of the vehicle 100.

In addition, if the front/rear information detection device 43 includes a camera, the ECU 90 may be configured to determine which of multiple lanes the vehicle 100 is traveling in based on an image captured by the camera.

The ECU 90 can also obtain the following information based on the road information Iroad, the current position of the vehicle 100, etc.: "The distance between the vehicle 100 and the branch road Rbranch when there is a branch road Rbranch ahead of the vehicle 100 (branch road reach distance D11)," "The distance between the vehicle 100 and the toll gate when the vehicle 100 is traveling on the main road Rmain of the expressway Rhigh and there is a toll gate on the main road Rmain of the expressway Rhigh ahead of the vehicle 100 (toll gate reach distance D12)," and "The distance between the vehicle 100 and the downhill slope when there is a downhill slope ahead of the vehicle 100 (downhill slope reach distance D13)."

In this example, the branch road Rbranch is a road that branches off from the main road Rmain of the expressway Rhigh, as shown in FIG. 3, and is, for example, "a road that connects the main road Rmain of the expressway Rhigh with an exit of the expressway Rhigh", "a road that connects the main road Rmain of the expressway Rhigh with a service area, a parking area, etc.", and "a road that connects the main road Rmain of the expressway Rhigh with the main road Rmain of another expressway Rhigh".

<Receiving device>
The receiving device 53 is a device that receives a wireless signal coming from outside the vehicle 100, and in this example, receives a wireless signal representing information on traffic congestion on the road. The receiving device 53 is electrically connected to the ECU 90. The receiving device 53 transmits the received wireless signal to the ECU 90. The ECU 90 can identify the location of traffic congestion when traffic congestion occurs at a point ahead of the vehicle 100 based on the information (road information Iroad) represented by the wireless signal. Furthermore, the ECU 90 can obtain the distance (traffic congestion reach distance D14) between the vehicle 100 and the location of traffic congestion based on the location of traffic congestion and the current position of the vehicle 100, etc.

<Overview of operation of vehicle driving assistance device>
Next, there will be described an overview of the operation of the vehicle driving support device 10. The vehicle driving support device 10 determines whether or not the automatic acceleration/deceleration condition Cacc is satisfied, and if the automatic acceleration/deceleration condition Cacc is not satisfied, executes normal acceleration/deceleration control.

Normal acceleration/deceleration control is a control that controls the operation of the drive device 21 so that the required driving force Pd_req is output when the required driving force Pd_req obtained from the accelerator pedal operation amount AP and the vehicle speed V0 of the vehicle 100 is greater than zero, and controls the operation of the brake device 22 so that the required braking force Pb_req is output when the required braking force Pb_req obtained from the brake pedal operation amount BP is greater than zero.

On the other hand, the vehicle driving assistance device 10 executes automatic acceleration/deceleration control when the automatic acceleration/deceleration condition Cacc is satisfied. When the vehicle driving assistance device 10 determines that the driver has requested the execution of automatic acceleration/deceleration control, the vehicle driving assistance device 10 may be configured to determine that the automatic acceleration/deceleration condition Cacc is satisfied regardless of whether the accelerator pedal 31 or the brake pedal 33 is being operated by the driver. However, in this example, the vehicle driving assistance device 10 determines that the automatic acceleration/deceleration condition Cacc is satisfied if the driver has not operated either the accelerator pedal 31 or the brake pedal 33 when it determines that the driver has requested the execution of automatic acceleration/deceleration control.

When the vehicle driving assistance device 10 determines that the driver has requested the end of the automatic acceleration/deceleration control while the automatic acceleration/deceleration control is being executed, the vehicle driving assistance device 10 determines that the automatic acceleration/deceleration condition Cacc has not been satisfied (i.e., the condition for terminating the automatic acceleration/deceleration control (automatic acceleration/deceleration end condition Cend) has been satisfied). The vehicle driving assistance device 10 also determines that the automatic acceleration/deceleration condition Cacc has not been satisfied if the driver operates the accelerator pedal 31 or the brake pedal 33 while the automatic acceleration/deceleration control is being executed.

When automatic acceleration/deceleration control is being performed and a preceding vehicle 101 is present, the vehicle driving assistance device 10 performs follow-up driving control as the automatic acceleration/deceleration control. Follow-up driving control is a control that automatically accelerates or decelerates the host vehicle 100 so that the forward inter-vehicle distance D1 is maintained at the set forward inter-vehicle distance D1set.

When performing follow-up cruise control, the vehicle driving assistance device 10 calculates the acceleration G of the host vehicle 100 required to control the forward inter-vehicle distance D1 to the set forward inter-vehicle distance D1set as the required acceleration Greq. The vehicle driving assistance device 10 then calculates the required driving force Pd_req or the required braking force Pb_req to achieve the required acceleration Greq, and automatically accelerates or decelerates the host vehicle 100 by controlling the operation of the driving device 21 and/or the braking device 22 so that the required driving force Pd_req or the required braking force Pb_req is output.

As a result, the host vehicle 100 travels following the preceding vehicle 101. In other words, the host vehicle 100 is automatically accelerated or decelerated so that the vehicle speed V0 of the host vehicle 100 becomes equal to the vehicle speed V1 of the preceding vehicle 101. Therefore, the following travel control can be said to be automatic acceleration/deceleration control that controls the vehicle speed V0 of the host vehicle 100 to a target vehicle speed (vehicle speed V1 of the preceding vehicle 101).

On the other hand, when automatic acceleration/deceleration control is being performed, if there is no preceding vehicle 101, the vehicle driving assistance device 10 performs constant speed control. Constant speed control is a control that automatically accelerates or decelerates the host vehicle 100 so that the vehicle speed V0 of the host vehicle 100 is maintained at the set vehicle speed Vset.

When performing constant speed control, the vehicle driving assistance device 10 calculates the acceleration G of the host vehicle 100 required to control the vehicle speed V0 of the host vehicle 100 to the set vehicle speed Vset as the required acceleration Greq. The vehicle driving assistance device 10 then calculates the required driving force Pd_req or the required braking force Pb_req to achieve the required acceleration Greq, and accelerates or decelerates the host vehicle 100 by controlling the operation of the driving device 21 and/or the braking device 22 so that the required driving force Pd_req or the required braking force Pb_req is output.

As a result, the host vehicle 100 travels at the set vehicle speed Vset. In other words, the host vehicle 100 is automatically accelerated or decelerated so that the vehicle speed V0 of the host vehicle 100 becomes the set vehicle speed Vset. Therefore, the constant speed control can be said to be automatic acceleration/deceleration control that controls the vehicle speed V0 of the host vehicle 100 to the target vehicle speed (set vehicle speed Vset).

Furthermore, the vehicle driving assistance device 10 determines whether the deceleration condition Cdec is satisfied while the automatic acceleration/deceleration control is being executed. The deceleration condition Cdec is satisfied when it is predicted that the host vehicle 100 will decelerate when the host vehicle 100 has traveled a predetermined distance (predicted predetermined deceleration distance Dth), and is not satisfied when it is no longer predicted that the host vehicle 100 will decelerate.

For example, as shown in FIG. 3, the highway Rhigh has a road (branch road Rbranch) that branches off from the main road Rmain. When a vehicle enters the branch road Rbranch from the main road Rmain of the highway Rhigh, the vehicle may be decelerated.

In this example, when the vehicle driving assistance device 10 determines based on the road information Iroad that the branch road Rbranch exists ahead of the vehicle 100 while the vehicle 100 is traveling on the main road Rmain of the expressway Rhigh, the vehicle driving assistance device 10 determines whether the vehicle 100 is traveling in the lane on the side where the branch road Rbranch is provided (the leftmost lane LN1 in the example shown in FIG. 3) among the multiple lanes LN1 to LN3 provided on the main road Rmain. When the vehicle driving assistance device 10 determines that the vehicle 100 is traveling in the lane on the side where the branch road Rbranch is provided, the vehicle driving assistance device 10 acquires the distance from the current position of the vehicle 100 to the branch road Rbranch (branch road reaching distance D11) as the deceleration prediction distance Ddec. Then, when the deceleration prediction distance Ddec becomes equal to a predetermined distance (predetermined deceleration prediction distance Dth), the vehicle driving assistance device 10 predicts that the vehicle 100 will decelerate when the vehicle 100 has traveled the predetermined deceleration prediction distance Dth.

Furthermore, if a toll booth is installed on the main road Rmain of the expressway Rhigh on which the vehicle is traveling, the vehicle may also slow down when it approaches the toll booth. Furthermore, if the road ahead of the vehicle is downhill, the vehicle may also slow down when it approaches the downhill slope and while it is traveling downhill. Furthermore, if there is a traffic jam ahead of the vehicle, the vehicle may also slow down when it approaches the area where the traffic jam is occurring.

When the vehicle driving assistance device 10 determines that a toll gate is present ahead of the vehicle 100 based on the road information Iroad while the vehicle 100 is traveling on the main lane Rmain of the expressway Rhigh, the vehicle driving assistance device 10 acquires the distance from the vehicle 100 to the toll gate (toll gate arrival distance D12) as the predicted deceleration distance Ddec. Then, when the predicted deceleration distance Ddec becomes equal to the predetermined predicted deceleration distance Dth, the vehicle driving assistance device 10 predicts that the vehicle 100 will decelerate when it has traveled the predetermined predicted deceleration distance Dth.

When the vehicle driving assistance device 10 determines that a downhill slope exists ahead of the vehicle 100 based on the road information Iroad, it acquires the distance from the vehicle 100 to the downhill slope (downhill reach distance D13) as the deceleration prediction distance Ddec. Then, when the deceleration prediction distance Ddec becomes equal to the predetermined deceleration prediction distance Dth, the vehicle driving assistance device 10 predicts that the vehicle 100 will decelerate when it has traveled the predetermined deceleration prediction distance Dth.

When the vehicle driving assistance device 10 determines that a traffic jam has occurred ahead of the vehicle 100 based on the road information Iroad, it acquires the distance from the vehicle 100 to the location where the traffic jam has occurred (traffic jam arrival distance D14) as the deceleration prediction distance Ddec. Then, when the deceleration prediction distance Ddec becomes equal to the predetermined deceleration prediction distance Dth, the vehicle driving assistance device 10 predicts that the vehicle 100 will decelerate when it has traveled the predetermined deceleration prediction distance Dth.

In addition to the above conditions, the deceleration condition Cdec may also include a condition that no following vehicle 102 is present.

When the deceleration condition Cdec is met while automatic acceleration/deceleration control is being performed, the vehicle driving assistance device 10 determines whether the eco-driving condition Ceco is met.

When the eco-driving condition Ceco is satisfied, the vehicle driving assistance device 10 suspends the automatic acceleration/deceleration control and calculates the acceleration G at which the required driving force Pd_req becomes zero as the required acceleration Greq. The vehicle driving assistance device 10 then calculates the required driving force Pd_req to achieve the required acceleration Greq, and executes coasting control to coast the host vehicle 100 by controlling the operation of the drive device 21 so that the required driving force Pd_req is output from the drive device 21 (i.e., so that the driving force output from the drive device 21 becomes zero). This causes the host vehicle 100 to decelerate.

In addition, when the drive device 21 includes a motor, the vehicle driving assistance device 10 may be configured to execute coasting control to coast the host vehicle 100 by rotating the motor using the running energy of the host vehicle 100 to regenerate power when coasting the host vehicle 100.

In addition, if the eco-driving condition Ceco is not met, the vehicle driving assistance device 10 continues automatic acceleration/deceleration control.

According to the vehicle driving assistance device 10, for example, when the deceleration condition Cdec and the eco-driving condition Ceco are satisfied while constant speed control is being executed, the vehicle speed V0 of the host vehicle 100 changes as shown in FIG. 4. In the example shown in FIG. 4, the automatic acceleration/deceleration condition Cacc and the eco-driving condition Ceco are satisfied at time t40. At this time, the preceding vehicle 101 is not present, so constant speed control is started. Then, since the vehicle speed V0 of the host vehicle 100 is lower than the set vehicle speed Vset at this time, the host vehicle 100 is automatically accelerated, and the vehicle speed V0 of the host vehicle 100 reaches the set vehicle speed Vset at time t41. Thereafter, the vehicle speed V0 of the host vehicle 100 is maintained at the set vehicle speed Vset.

Then, at time t42, the deceleration condition Cdec is met. At this time, the eco-driving condition Ceco is met, so the constant speed control is interrupted and coasting control is started. Therefore, the vehicle speed V0 of the host vehicle 100 gradually decreases.

＜Effects＞
According to the vehicle driving assistance device 10, when it is predicted that the host vehicle 100 will decelerate when the host vehicle 100 has traveled a predetermined deceleration predicted distance Dth, the host vehicle 100 starts coasting. Therefore, the vehicle speed V0 is relatively small when the host vehicle 100 approaches a place where deceleration will occur. Therefore, the degree of braking required to reduce the vehicle speed V0 of the host vehicle 100 to a desired vehicle speed at that time is small, and as a result, the energy consumption of the host vehicle 100 can be suppressed to a low level.

<Specific Operation of Vehicle Driving Assistance Device>
Next, a specific operation of the vehicle driving support device 10 will be described. The CPU of the ECU 90 of the vehicle driving support device 10 executes the routine shown in Fig. 5 every time a predetermined calculation time elapses. Therefore, at a predetermined timing, the CPU starts the process from step 500 in Fig. 5, and advances the process to step 510 to determine whether the automatic acceleration/deceleration condition Cacc is satisfied.

If the CPU judges "Yes" in step 510, the process proceeds to step 520, where it judges whether the deceleration condition Cdec is satisfied. If the CPU judges "Yes" in step 520, the process proceeds to step 530, where it judges whether the eco-driving condition Ceco is satisfied. If the CPU judges "Yes" in step 530, the process proceeds to step 540, where it executes coasting control. This causes the host vehicle 100 to decelerate, and the vehicle speed V0 becomes smaller. Next, the CPU proceeds to step 595, where it temporarily ends this routine.

On the other hand, if the CPU determines "No" in step 530, the process proceeds to step 550, where it determines whether or not a preceding vehicle 101 is present. If the CPU determines "Yes" in step 550, the process proceeds to step 560, where it executes follow-up cruise control. Next, the CPU proceeds to step 595, where it temporarily ends this routine.

On the other hand, if the CPU determines "No" in step 550, the process proceeds to step 570 and executes constant speed control. Next, the CPU proceeds to step 595 and ends this routine.

Even if the CPU judges "No" in step 520, it advances the process to step 550 and judges whether or not a preceding vehicle 101 is present. If the CPU judges "Yes" in step 550, it advances the process to step 560 and executes follow-up cruise control, and if the CPU judges "No" in step 550, it advances the process to step 570 and executes constant speed control. Next, the CPU advances the process to step 595 and temporarily ends this routine.

If the CPU determines "No" in step 510, the CPU advances the process to step 580 and executes normal acceleration/deceleration control. Next, the CPU advances the process to step 595 and ends this routine.

The above is the specific operation of the vehicle driving assistance device 10.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

10...vehicle driving support device, 21...drive device, 22...braking device, 41...automatic acceleration/deceleration control device, 42...eco-driving control device, 43...front/rear information detection device, 50...road information acquisition device, 90...ECU, 100...own vehicle, 101...preceding vehicle, 102...following vehicle, Rhigh...expressway, Rmain...main line of expressway, Rbranch...branch road

Claims (1)

1. A vehicle driving assistance device that performs automatic acceleration/deceleration control to automatically accelerate and decelerate a host vehicle so that a forward vehicle distance, which is a distance between the host vehicle and a preceding vehicle traveling in front of the host vehicle on a lane in which the host vehicle is traveling, is maintained at a set forward vehicle distance ,
When the host vehicle is traveling on a highway during execution of the automatic acceleration/deceleration control, and a branch road that branches off from a main road of the highway is present ahead of the host vehicle and is a point where the host vehicle is predicted to decelerate , and the host vehicle is traveling in a lane on the side of a plurality of lanes on the main road on which the branch road is located, and when the distance to the branch road becomes equal to or shorter than a predetermined distance, if a request is made for the host vehicle to travel in an eco mode, the automatic acceleration/deceleration control is interrupted and the host vehicle is coasted.
Vehicle driving assistance device.

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