Vehicle driving support device

Abstract

A vehicle driving support device performs driving support control for automatically controlling the acceleration of a vehicle to automatically drive the vehicle. The driving support control includes a first constant speed control and a second constant speed control, wherein the first constant speed control is a control for automatically controlling the acceleration of the vehicle in order to maintain the speed of the vehicle at a set speed, using a first speed range including the set speed as a reference, and the second constant speed control is a control for automatically controlling the acceleration of the vehicle in order to maintain the speed of the vehicle at the set speed, using a second speed range including the set speed as a reference. The second speed range is set to a range wider than the first speed range. The vehicle driving support device switches the driving support control between the first constant speed control and the second constant speed control according to the driving state of the vehicle.

Description

Technical Field

[0001] The present invention relates to a vehicle driving support device. Background Art

[0002] There are known vehicles that have an internal combustion engine and a motor as a drive device that outputs a driving force (vehicle driving force) applied to the vehicle. In such a vehicle, an HV mode in which the vehicle driving force is output from both the internal combustion engine and the motor, and an EV mode in which the vehicle driving force is output only from the motor can be arbitrarily selected. Japanese Patent Application Laid-Open No. 2015-182629 describes a vehicle that determines which mode to select between the HV mode and the EV mode in a manner that makes the energy efficiency of the drive device when outputting the vehicle driving force as high as possible.

[0003] A vehicle is known that is configured to perform a constant speed control, wherein the constant speed control is a control that automatically controls the acceleration of the vehicle in such a manner that the vehicle speed is controlled to a vehicle speed set by a driver (set vehicle speed). When performing this constant speed control, it is also desirable to control the acceleration of the vehicle in such a manner that the energy efficiency of the drive device when outputting the vehicle driving force is as high as possible.

[0004] The present invention provides a vehicle driving support device capable of performing a constant speed control to control a vehicle speed to a set vehicle speed with the highest possible energy efficiency.

[0005] A vehicle driving support device according to a technical solution of the present invention includes a controller, which performs driving support control for automatically controlling the acceleration of the vehicle so that the vehicle automatically drives. The driving support control includes a first constant speed control and a second constant speed control, wherein the first constant speed control is a control for automatically controlling the acceleration of the vehicle in order to maintain the speed of the vehicle at a set speed, using a first speed range including the set speed as a reference, and the second constant speed control is a control for automatically controlling the acceleration of the vehicle in order to maintain the speed of the vehicle at the set speed, using a second speed range including the set speed as a reference. In addition, the second speed range is set to a range wider than the first speed range. Furthermore, the controller is configured to switch the driving support control between the first constant speed control and the second constant speed control according to the driving state of the vehicle.

[0006] Usually, when the vehicle speed is controlled to a certain specific speed, if the vehicle speed is controlled while allowing a wide range of speed changes, the degree of freedom of control when controlling the operation of the drive device in order to output the driving force (vehicle driving force) applied to the vehicle increases. As a result, a control with higher energy efficiency can be selected as the control of the drive device. According to the above technical solution of the present invention, a first constant speed control based on a first speed range with a narrower range of allowed speed changes and a second constant speed control based on a second speed range with a wider range of allowed speed changes are prepared as driving support controls, and the second constant speed control is executed according to the driving state of the vehicle. Therefore, the vehicle can be driven while the speed of the vehicle is controlled to a set speed with higher energy efficiency.

[0007] In addition, the vehicle driving support device involved in the above technical solution of the present invention may further include a detection device, and the detection device is configured to detect a leading vehicle traveling in the same lane as the host vehicle and within a predetermined leading vehicle determination distance in front of the host vehicle, and a following vehicle traveling in the same lane as the host vehicle and within a predetermined following vehicle determination distance behind the host vehicle. The controller may be configured to execute the first constant speed control when there is no request to execute the second constant speed control when both the leading vehicle and the following vehicle do not exist. The controller may be configured to execute the second constant speed control when there is a request to execute the second constant speed control when both the leading vehicle and the following vehicle do not exist.

[0008] In the case where neither the preceding vehicle nor the following vehicle exists, even if the speed of the host vehicle is controlled while allowing a large speed variation, the distance between the host vehicle and the preceding vehicle and the distance between the host vehicle and the following vehicle will not become extremely short. According to the above configuration, when the second constant speed control is requested to be executed when neither the preceding vehicle nor the following vehicle exists, the second constant speed control is executed. Therefore, the second driving control can be executed without causing the distance between the host vehicle and the preceding vehicle and the distance between the host vehicle and the following vehicle to become extremely short.

[0009] In the vehicle driving support device, the second constant speed control may include a deceleration control for reducing the speed of the host vehicle and an acceleration control for increasing the speed of the host vehicle. The controller may be configured to, when executing the second constant speed control, execute the deceleration control when the speed of the host vehicle increases and reaches the upper limit of the second speed range, and execute the acceleration control when the speed of the host vehicle decreases and reaches the lower limit of the second speed range.

[0010] According to the above configuration, when the speed of the host vehicle increases and reaches the upper limit of the second speed range, the deceleration control is executed to reduce the speed of the host vehicle, and when the speed of the host vehicle reaches the lower limit of the second speed range, the acceleration control is executed to increase the speed of the host vehicle. Therefore, the average speed of the host vehicle is at least controlled to be near the set speed.

[0011] In addition, the vehicle driving support device according to the above technical solution of the present invention may further include a detection device, the detection device being configured to detect a preceding vehicle traveling in the same lane as the host vehicle and within a predetermined preceding vehicle determination distance in front of the host vehicle, and a following vehicle traveling in the same lane as the host vehicle and within a predetermined following vehicle determination distance behind the host vehicle. The controller may be configured to execute the first constant speed control when the execution of the second constant speed control is not requested when the preceding vehicle and the following vehicle are both absent. The controller may be configured to execute the second constant speed control when the execution of the second constant speed control is requested when the preceding vehicle and the following vehicle are both absent. Furthermore, the controller may be configured to execute a deceleration control for reducing the speed of the host vehicle when the execution of the second constant speed control is requested when the preceding vehicle exists and the following vehicle does not exist, and when the speed of the host vehicle is faster than the speed of the preceding vehicle and the difference between the speed of the host vehicle and the speed of the preceding vehicle is greater than the predetermined front approaching vehicle speed difference. The controller may be configured to, when the leading vehicle exists and the following vehicle does not exist, execute acceleration control for increasing the speed of the host vehicle when the second constant speed control is required to be executed, and the speed of the host vehicle is slower than the speed of the leading vehicle and the difference between the speed of the host vehicle and the speed of the leading vehicle is larger than a predetermined front departure speed difference and the speed of the host vehicle is slower than a lower limit of the second speed range.

[0012] When the speed of the host vehicle is faster than that of the preceding vehicle and the difference between their speeds is large, the distance between the host vehicle and the preceding vehicle may become extremely short. In such a case, the deceleration control is performed. Therefore, the distance between the host vehicle and the preceding vehicle can be prevented from becoming extremely short.

[0013] In addition, when the speed of the host vehicle is slower than that of the preceding vehicle and the difference between their speeds is large and the speed of the host vehicle is too slow (the speed of the host vehicle is slower than the lower limit of the second speed range), the distance between the host vehicle and the preceding vehicle may become extremely long. In such a case, acceleration control is performed. Therefore, it is possible to prevent the distance between the host vehicle and the preceding vehicle from becoming extremely long.

[0014] In addition, the vehicle driving support device according to the above technical solution of the present invention may further include a detection device, the detection device being configured to detect a leading vehicle traveling in the same lane as the host vehicle and within a predetermined leading vehicle determination distance in front of the host vehicle, and a following vehicle traveling in the same lane as the host vehicle and within a predetermined following vehicle determination distance behind the host vehicle. The driving support control may include, for example, a follow-up driving control, which automatically controls the acceleration of the host vehicle in order to maintain the front vehicle distance between the leading vehicle and the host vehicle at a set front vehicle distance. The controller may be configured to execute the first constant speed control when there is no request to execute the second constant speed control when there is no request to execute the second constant speed control when there is no request to execute the second constant speed control. The controller may be configured to execute the second constant speed control when there is no request to execute the second constant speed control when there is no request to execute the second constant speed control. Furthermore, the controller may be configured to execute deceleration control for reducing the speed of the host vehicle when the preceding vehicle exists and the following vehicle does not exist, and the preceding vehicle distance is longer than a predetermined preceding middle distance shorter than the predetermined preceding vehicle determination distance, and the speed of the host vehicle is faster than the speed of the preceding vehicle, and the difference between the speed of the host vehicle and the speed of the preceding vehicle is larger than a predetermined preceding approaching vehicle speed difference. The controller may be configured to execute deceleration control when the preceding vehicle exists and the following vehicle does not exist, and the preceding vehicle distance is less than the predetermined preceding middle distance and longer than a predetermined preceding short distance shorter than the predetermined preceding middle distance. The controller may be configured to execute the following driving control when the preceding vehicle exists and the following vehicle does not exist, and the preceding vehicle distance is less than the predetermined preceding short distance, even when the second constant speed control is requested.

[0015] In a situation where the distance between the host vehicle and the preceding vehicle is short (in a situation where the front inter-vehicle distance is longer than the predetermined front intermediate distance but less than the predetermined preceding vehicle determination distance), the host vehicle is likely to be very close to the preceding vehicle if the speed of the host vehicle is faster than that of the preceding vehicle and the difference between their speeds is large. In such a situation, the deceleration control is executed. Therefore, it is possible to prevent the host vehicle from being very close to the preceding vehicle.

[0016] In addition, if a change in the situation occurs when the distance between the vehicle and the preceding vehicle is very short (when the distance between the vehicles ahead is longer than the predetermined short distance ahead but less than the predetermined medium distance ahead), even if the change is small, the vehicle may approach the preceding vehicle, and depending on the situation, the vehicle may come into contact with the preceding vehicle. In such a case, it is preferred to reduce the speed of the vehicle to avoid contact between the vehicle and the preceding vehicle before considering whether the speed of the vehicle is faster than that of the preceding vehicle. According to the above configuration, deceleration control is performed. Therefore, contact between the vehicle and the preceding vehicle can be prevented.

[0017] In addition, when the distance between the host vehicle and the preceding vehicle becomes extremely short (when the distance between the preceding vehicles becomes less than the predetermined preceding short distance), even if the deceleration control is executed to simply reduce the speed of the host vehicle, if the speed of the preceding vehicle suddenly decelerates, the host vehicle may contact the preceding vehicle. In such a case, the following driving control is executed. Thus, the host vehicle decelerates according to the distance between the host vehicle and the preceding vehicle, so that the contact between the host vehicle and the preceding vehicle can be prevented.

[0018] In addition, the vehicle driving support device involved in the above technical solution of the present invention may further include a detection device, and the detection device is configured to detect a leading vehicle traveling in the same lane as the host vehicle and within a predetermined leading vehicle determination distance in front of the host vehicle, and a following vehicle traveling in the same lane as the host vehicle and within a predetermined following vehicle determination distance behind the host vehicle. The controller may be configured to execute the first constant speed control when there is no request to execute the second constant speed control when both the leading vehicle and the following vehicle do not exist. The controller may be configured to execute the second constant speed control when there is a request to execute the second constant speed control when both the leading vehicle and the following vehicle do not exist. Furthermore, the controller may be configured to, when the preceding vehicle does not exist and the following vehicle exists, perform the acceleration control for increasing the vehicle speed of the host vehicle when the second constant speed control is required and the rear vehicle distance between the host vehicle and the following vehicle is longer than a predetermined rear close distance shorter than the predetermined following vehicle determination distance and the vehicle speed of the host vehicle is slower than the vehicle speed of the following vehicle and the difference between the vehicle speed of the host vehicle and the vehicle speed of the following vehicle is larger than a predetermined rear close vehicle speed difference. The controller may be configured to, when the preceding vehicle does not exist and the following vehicle exists, perform the acceleration control when the second constant speed control is required and the rear vehicle distance is less than the predetermined rear close distance and the vehicle speed of the host vehicle is slower than the upper limit of the second vehicle speed range. The controller may be configured to, when the preceding vehicle does not exist and the following vehicle exists, when the rear vehicle distance is less than the predetermined rear close distance and the vehicle speed of the host vehicle is greater than the upper limit of the second vehicle speed range, execute the first constant speed control even when execution of the second constant speed control is requested.

[0019] In a situation where the distance between the host vehicle and the following vehicle is short (in a situation where the rear vehicle distance is longer than the predetermined rear close distance but less than the predetermined following vehicle determination distance), if the speed of the host vehicle is slower than that of the following vehicle and the difference between their speeds is large, the following vehicle may be very close to the host vehicle. In such a situation, acceleration control is performed. Therefore, it is possible to prevent the following vehicle from being very close to the host vehicle.

[0020] In addition, if a change in the situation occurs when the distance between the host vehicle and the following vehicle is very short (when the distance between the rear vehicles is less than the predetermined rear close distance), the following vehicle may approach the host vehicle even if the change is small, and depending on the situation, the following vehicle may come into contact with the host vehicle. In such a case, if the speed of the host vehicle is not faster than the allowable range (if the speed of the host vehicle is slower than the upper limit of the second speed range), it is preferred to increase the speed of the host vehicle to avoid contact between the following vehicle and the host vehicle. According to the above configuration, acceleration control is performed when the speed of the host vehicle is not faster than the allowable range. Therefore, contact between the following vehicle and the host vehicle can be prevented.

[0021] In addition, as described above, in the case where the distance between the host vehicle and the following vehicle is very short (in the case where the distance between the rear vehicles is less than the predetermined rear short distance), the following vehicle may contact the host vehicle, so it is effective to perform acceleration control in order to avoid such contact. However, at this time, if the speed of the host vehicle exceeds the upper limit of the second speed range, the speed of the host vehicle will greatly exceed the upper limit, so the average speed of the host vehicle is no longer controlled near the set speed. Therefore, from the perspective of controlling the average speed of the host vehicle near the set speed, it is not desirable to perform acceleration control. On the other hand, in the case where the distance between the host vehicle and the following vehicle is very short although the speed of the host vehicle exceeds the upper limit of the second speed range (in the case where the distance between the rear vehicles is less than the predetermined rear short distance and the speed of the host vehicle is more than the upper limit of the second speed range), the speed of the following vehicle itself may be too fast. If the upper limit and lower limit of the second speed range are used as thresholds to control the speed of the host vehicle in such a case, the variation range of the speed of the host vehicle will become larger, so it is possible to increase the possibility of the following vehicle contacting the host vehicle. In such a case, the first constant speed control is executed. Therefore, the vehicle speed of the host vehicle can be controlled to the set vehicle speed while avoiding the following vehicle from coming into contact with the host vehicle.

[0022] In addition, the vehicle driving support device involved in the above technical solution of the present invention may further include a detection device, and the detection device is configured to detect a leading vehicle traveling in the same lane as the host vehicle and within a predetermined leading vehicle determination distance in front of the host vehicle. In addition, the driving support control may include, for example, a follow-up driving control, which automatically controls the acceleration of the host vehicle in order to maintain the front vehicle distance between the leading vehicle and the host vehicle at the set front vehicle distance. In this case, the controller may be configured to execute the follow-up driving control when there is a leading vehicle and when there is no request to execute the second constant speed control.

[0023] Thus, if there is no request to execute the second constant speed control when there is a preceding vehicle, the host vehicle can be caused to travel following the preceding vehicle.

[0024] The vehicle driving support device may include a drive device that outputs a driving force applied to the host vehicle. In this case, the controller may be configured to accelerate and decelerate the host vehicle in such a manner that the speed at which the vehicle speed converges to the set vehicle speed becomes greater than a predetermined speed when the first constant speed control is executed. The controller may be configured to accelerate and decelerate the host vehicle in such a manner that the energy efficiency of the drive device when the drive device outputs the driving force becomes greater than a predetermined efficiency when the second constant speed control is executed.

[0025] Thus, when the first constant speed control is executed, the vehicle is accelerated and decelerated in such a manner that the convergence speed of the vehicle speed to the set speed becomes greater than a predetermined speed, so the vehicle speed of the vehicle can be controlled to the set speed with a small speed change amplitude compared to the case where the second constant speed control is executed. In addition, when the second constant speed control is executed, the vehicle is accelerated and decelerated in such a manner that the energy efficiency of the drive device when the drive device outputs the driving force becomes greater than a predetermined efficiency, so the vehicle speed of the vehicle can be controlled to the set speed with high energy efficiency compared to the case where the first constant speed control is executed.

[0026] 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 will be easily understood from the description of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0028] Figure 1 1 is a diagram showing a vehicle driving support device according to an embodiment of the present invention and a vehicle (host vehicle) on which the vehicle driving support device is mounted.

[0029] Figure 2 It is a diagram showing the front vehicle distance and the rear vehicle distance.

[0030] Figure 3A This is a diagram showing the vehicle speed and the like of the host vehicle when the normal constant speed control (first constant speed control) is executed.

[0031] Figure 3B This is a diagram showing the vehicle speed and the like of the host vehicle when the energy-saving constant speed control (second constant speed control) is executed.

[0032] Figure 4AThis is a diagram showing the vehicle speed of the host vehicle and the like when the first acceleration / deceleration control is executed in a state where the vehicle speed of the host vehicle is faster than the vehicle speed of the preceding vehicle.

[0033] Figure 4B This is a diagram showing the vehicle speed of the host vehicle and the like when the first acceleration / deceleration control is executed in a state where the vehicle speed of the host vehicle is slower than the vehicle speed of the preceding vehicle.

[0034] Figure 5 It is a diagram showing the preceding vehicle distance and the like when the second acceleration / deceleration control is executed.

[0035] Fig. 6A It is a diagram showing the vehicle speed and the like of the host vehicle when the third acceleration / deceleration control is executed.

[0036] Figure 6B It is a diagram showing the vehicle speed and the like of the host vehicle when the fourth acceleration / deceleration control is executed.

[0037] Figure 7 It is a diagram showing the energy efficiency of the internal combustion engine, the energy efficiency of the motor, and the required driving force.

[0038] Figure 8 This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention.

[0039] Fig. 9 This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention.

[0040] Fig.10 This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention.

[0041] Fig.11 This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention.

[0042] Fig.12 This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention.

[0043] Fig.13 This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention.

[0044] Fig.14 This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention.

[0045] Fig.15 This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention.

[0046] Fig.16This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention. DETAILED DESCRIPTION

[0047] Hereinafter, a vehicle driving support device according to an embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 2 shows a vehicle driving support device 10 according to an embodiment of the present invention. The vehicle driving support device 10 is mounted on a host vehicle 100 .

[0048] The vehicle driving support device 10 includes an electronic control unit (ECU) 90. The ECU 90 includes a microcomputer as a main part. The microcomputer includes a CPU, a ROM, a RAM, a nonvolatile memory, an interface, etc. The CPU implements various functions by executing instructions, programs, or routines stored in the ROM.

[0049] The vehicle 100 is equipped with a driving device 21 and a braking device 22 .

[0050] The drive device 21 is a device that outputs a driving force applied to the vehicle 100 in order to make the vehicle 100 travel, such as an internal combustion engine and a motor. The drive device 21 is electrically connected to the ECU 90. The ECU 90 can control the driving force output from the drive device 21 by controlling the operation of the drive device 21.

[0051] The brake device 22 is a device that outputs a braking force applied to the vehicle 100 in order to brake the vehicle 100, and is, for example, a brake device. The brake device 22 is electrically connected to the ECU 90. The ECU 90 can control the braking force output from the brake device 22 by controlling the operation of the brake device 22.

[0052] 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 , a driving support operator 41 , an energy-saving driving operator 42 , a front and rear information detection device 43 , and a vehicle speed detection device 44 .

[0053] 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 of the detected operation amount to the ECU 90. Based on the information, the ECU 90 acquires the operation amount of the accelerator pedal 31 as the accelerator pedal operation amount AP.

[0054] When the accelerator pedal operation amount AP is greater than zero, the ECU 90 obtains the required driving force Pd_req by calculation based on the accelerator pedal operation amount AP and the vehicle speed Vown of the host vehicle 100. The required driving force Pd_req is the driving force required to be output by the drive device 21. The ECU 90 controls the operation of the drive device 21 to output the required driving force Pd_req.

[0055] 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 of the detected operation amount to the ECU 90. Based on the information, the ECU 90 acquires the operation amount of the brake pedal 33 as the brake pedal operation amount BP.

[0056] When the brake pedal operation amount BP is greater than zero, the ECU 90 obtains the required braking force Pb_req by calculation based on the brake pedal operation amount BP. The required braking force Pb_req is the braking force required to be output by the brake device 22. The ECU 90 controls the operation of the brake device 22 to output the required braking force Pb_req.

[0057] The driving support operator 41 is a device operated by the driver of the vehicle 100. The driving support operator 41 is a device composed of switches, buttons, etc. These switches, buttons, etc. are provided on the steering wheel of the vehicle 100 or on a lever attached to the steering column of the vehicle 100, for example.

[0058] In this example, the driving support operator 41 includes a driving support selection switch, a vehicle speed setting switch, a vehicle speed increase button, a vehicle speed decrease button, and an inter-vehicle distance setting button. The driving support operator 41 is electrically connected to the ECU 90 .

[0059] When the driving support control described later is not being executed, the driver operates the driving support selection switch, a signal is sent from the driving support operator 41 to the ECU 90. When receiving the signal, the ECU 90 determines that the driver has requested execution of the driving support control.

[0060] On the other hand, when the driving support control is executed, if the driver operates the driving support selection switch, a signal is sent from the driving support operator 41 to the ECU 90. When receiving the signal, the ECU 90 determines that the driver requests to terminate the driving support control.

[0061] When the driver operates the vehicle speed setting switch during driving support control, a signal is sent from the driving support operator 41 to the ECU 90. Upon receiving the signal, the ECU 90 sets the vehicle speed Vown of the host vehicle 100 at that time as the set vehicle speed Vset in driving support control.

[0062] In addition, if the vehicle speed increase button is operated by the driver during the driving support control, a signal is sent from the driving support operator 41 to the ECU 90. Upon receiving the signal, the ECU 90 increases the set vehicle speed Vset. On the other hand, if the vehicle speed decrease button is operated by the driver during the driving support control, a signal is sent from the driving support operator 41 to the ECU 90. Upon receiving the signal, the ECU 90 decreases the set vehicle speed Vset.

[0063] In addition, when the driver operates the inter-vehicle distance setting button during the execution of the driving support control, a signal is sent from the driving support operator 41 to the ECU 90. This signal is a signal (required inter-vehicle distance signal) indicating the distance (required inter-vehicle distance Dfr_req) required by the driver for the distance (front inter-vehicle distance Dfr) between the host vehicle 100 and the preceding vehicle 200fr in the following driving control as the driving support control by operating the inter-vehicle distance setting button.

[0064] like Figure 2 As shown, the front vehicle distance Dfr is the distance between the host vehicle 100 and the preceding vehicle 200fr. In addition, in this example, the preceding vehicle 200fr is a vehicle traveling in front of the host vehicle 100 in the lane (host lane LN) in which the host vehicle 100 is traveling, and is a vehicle whose distance from the host vehicle 100 (front vehicle distance Dfr) is less than the predetermined preceding vehicle determination distance Dfr_th.

[0065] In this example, there are three types of required front vehicle distances Dfr_req that can be selected by the driver by operating the vehicle distance setting button: a long distance, a medium distance, and a short distance.

[0066] When receiving the required vehicle distance signal, ECU90 may also set the distance required as the required front vehicle distance Dfr_req as the set front vehicle distance Dfr_set without considering the vehicle speed Vown of the vehicle 100 at that time. However, in this example, the set front vehicle distance Dfr_set is set based on the vehicle speed Vown at that time and the required front vehicle distance Dfr_req.

[0067] Specifically, ECU90 sets the front vehicle distance Dfr in which the time (arrival prediction time TTC) obtained by dividing the vehicle speed Vown at this time becomes the pre-set time (scheduled arrival prediction time TTCref) as the set front vehicle distance Dfr_set. That is, ECU90 sets the front vehicle distance Dfr in which the relationship between the vehicle speed Vown at this time, the scheduled arrival prediction time TTCref, and the front vehicle distance Dfr becomes the relationship of the following formula 1 as the set front vehicle distance Dfr_set.

[0068] TTCref=Dfr / Vown···(1)

[0069] The estimated arrival time TTCref is a long time TTClong when the required front vehicle distance Dfr_req is a long distance, a medium time TTCmid when the required front vehicle distance Dfr_req is a medium distance, and a short time TTCshort when the required front vehicle distance Dfr_req is a short distance.

[0070] Furthermore, the scheduled preceding vehicle determination distance Dfr_th is set to a distance longer than the set preceding vehicle distance Dfr_set.

[0071] The energy-saving travel operator 42 is a device operated by the driver of the vehicle 100. The energy-saving travel operator 42 is a device composed of switches, buttons, etc. These switches, buttons, etc. are provided on the steering wheel of the vehicle 100, or on a lever mounted on the steering column of the vehicle 100, for example.

[0072] When the energy-saving travel operator 42 is operated in the state of being operated to the off position, it becomes the on position. When the energy-saving travel operator 42 is operated to the on position, it sends a specific signal to the ECU 90. When the ECU 90 receives the signal, it determines that the driver requests to execute the energy-saving constant speed control (second constant speed control) described later. When the ECU 90 determines that the driver requests to execute the energy-saving constant speed control (second constant speed control), it determines that the energy-saving travel condition Ceco is met.

[0073] On the other hand, the energy-saving travel operator 42 is in the off position when it is operated while being in the on position. When the energy-saving travel operator 42 is operated to the off position, it sends a specific signal to the ECU 90. When the ECU 90 receives the signal, it determines that the driver does not request the execution of the energy-saving constant speed control (the second constant speed control). When the ECU 90 determines that the driver does not request the execution of the energy-saving constant speed control (the second constant speed control), it determines that the energy-saving travel condition Ceco is not satisfied.

[0074] The front and rear information detection device 43 detects information in front of and behind the vehicle 100. The front and rear information detection device 43 is, for example, a camera, a radar sensor (millimeter wave radar, etc.), an ultrasonic sensor (clearance sonar), or a laser radar (LiDAR).

[0075] The front and rear information detection device 43 is electrically connected to the ECU 90. The front and rear information detection device 43 sends information about the front of the host vehicle 100 (front information) and information about the rear of the host vehicle 100 (rear information) to the ECU 90. The ECU 90 obtains the distance between the preceding vehicle 200fr and the host vehicle 100 (front inter-vehicle distance Dfr), the vehicle speed Vfr of the preceding vehicle 200fr, etc. based on the front information. In addition, the ECU 90 obtains the distance between the following vehicle 200rr and the host vehicle 100 (rear inter-vehicle distance Drr), the vehicle speed Vrr of the following vehicle 200rr, etc. based on the rear information.

[0076] like Figure 2 As shown, the rear vehicle distance Drr is the distance between the host vehicle 100 and the following vehicle 200rr. In addition, in this example, the following vehicle 200rr is a vehicle traveling behind the host vehicle 100 in the lane (host lane LN) in which the host vehicle 100 is traveling, and is a vehicle whose distance from the host vehicle 100 (rear vehicle distance Drr) is less than the predetermined following vehicle determination distance Drr_th.

[0077] The vehicle speed detection device 44 is a device for detecting the vehicle speed Vown 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 Vown of the host vehicle 100 and transmits the information of the vehicle speed Vown to the ECU 90. The ECU 90 acquires the vehicle speed Vown based on the information.

[0078] Overview of the operation of the vehicle driving support device

[0079] Next, an overview of the operation of the vehicle driving support device 10 is described. The vehicle driving support device 10 performs the driving support control when requested to perform the driving support control. The driving support control includes the normal driving support control and the energy-saving driving support control. The normal driving support control includes the following driving control and the normal constant speed control (the first constant speed control), and the energy-saving driving support control includes the energy-saving constant speed control (the second constant speed control), the first acceleration and deceleration control, the second acceleration and deceleration control, the third acceleration and deceleration control, and the fourth acceleration and deceleration control.

[0080] Normal driving support control

[0081] The vehicle driving support device 10 executes the normal driving support control when the eco-driving condition Ceco is not satisfied while the driving support execution condition Cacc is satisfied.

[0082] Although the vehicle driving assistance device 10 can be configured to determine that the driving assistance execution condition Cacc is satisfied when it is determined that the driver requests the execution of driving assistance control, regardless of whether the driver operates the accelerator pedal 31 or the brake pedal 33, in this example, when it is determined that the driver requests the execution of driving assistance control and neither the accelerator pedal 31 nor the brake pedal 33 is operated by the driver, the driving assistance execution condition Cacc is determined to be satisfied.

[0083] In addition, when the vehicle driving support device 10 determines that the driver requests to terminate the driving support control while executing the driving support control, it is determined that the driving support execution condition Cacc becomes unsatisfied, that is, the condition for terminating the driving support control (driving support control termination condition Cend) is satisfied. In addition, when the driver operates the accelerator pedal 31 or the brake pedal 33 while executing the driving support control, the vehicle driving support device 10 also determines that the driving support execution condition Cacc becomes unsatisfied.

[0084] The vehicle driving support device 10 performs the following driving control as the normal driving support control when there is a leading vehicle 200fr. In addition, when there is a vehicle traveling in front of the host vehicle 100 on the own lane LN and the front vehicle distance Dfr is less than the predetermined leading vehicle determination distance Dfr_th, the vehicle driving support device 10 determines that there is a leading vehicle 200fr.

[0085] On the other hand, when the preceding vehicle 200fr does not exist, the vehicle driving support device 10 executes the normal constant speed control (first constant speed control) as the normal travel support control.

[0086] Furthermore, when the front inter-vehicle distance Dfr is equal to or smaller than the predetermined preceding vehicle determination distance Dfr_th, the vehicle driving support device 10 determines that the preceding vehicle 200fr exists.

[0087] Follow-up driving control

[0088] When executing the following travel control, the vehicle driving support device 10 accelerates or decelerates the host vehicle 100 to maintain the front inter-vehicle distance Dfr at the set front inter-vehicle distance Dfr_set, in other words, to maintain the predicted arrival time TTC at the predetermined predicted arrival time TTCref.

[0089] In this example, when the vehicle driving support device 10 performs the following driving control, it calculates the acceleration G of the host vehicle 100 required to control the arrival prediction time TTC to the predetermined arrival prediction time TTCref as the required acceleration Greq. At this time, the vehicle driving support device 10 calculates the required acceleration Greq in such a way that the speed (convergence speed) at which the arrival prediction time TTC converges to the predetermined arrival prediction time TTCref becomes greater than the predetermined speed.

[0090] Then, the vehicle driving support device 10 calculates the required driving force Pd_req or the required braking force Pb_req for achieving the required acceleration Greq, and controls the operation of the driving device 21 and / or the braking device 22 in such a manner as to output the required driving force Pd_req or the required braking force Pb_req to accelerate or decelerate the vehicle 100. Therefore, as described above, the vehicle driving support device 10 calculates the required acceleration Greq in such a manner that the speed at which the predicted arrival time TTC converges to the predetermined predicted arrival time TTCref becomes greater than a predetermined speed, so that, as a result, acceleration or deceleration is performed in such a manner that the speed at which the predicted arrival time TTC converges to the predetermined predicted arrival time TTCref becomes greater than a predetermined speed.

[0091] Normal constant speed control (1st constant speed control)

[0092] In addition, when the vehicle driving support device 10 performs normal constant speed control (first constant speed control), the vehicle 100 is accelerated or decelerated in order to maintain the vehicle speed Vown of the vehicle 100 at the set vehicle speed Vset. Figure 3A As shown, the vehicle driving support device 10 accelerates the host vehicle 100 to increase the vehicle speed Vown when the vehicle speed Vown decreases and falls below the set vehicle speed Vset, and decelerates the host vehicle 100 to reduce the vehicle speed Vown when the vehicle speed Vown increases and exceeds the set vehicle speed Vset.

[0093] In this example, when the vehicle driving support device 10 performs normal constant speed control, it calculates the acceleration G of the host vehicle 100 required to control the vehicle speed Vown of the host vehicle 100 to the set vehicle speed Vset as the required acceleration Greq. At this time, the vehicle driving support device 10 calculates the required acceleration Greq in such a way that the speed (convergence speed) at which the vehicle speed Vown of the host vehicle 100 converges to the set vehicle speed Vset becomes greater than a predetermined speed.

[0094] Then, the vehicle driving support device 10 calculates the required driving force Pd_req or the required braking force Pb_req for achieving the required acceleration Greq, and controls the operation of the driving device 21 and / or the braking device 22 in such a manner as to output the required driving force Pd_req or the required braking force Pb_req to accelerate or decelerate the host vehicle 100. Therefore, as described above, the vehicle driving support device 10 calculates the required acceleration Greq in such a manner that the speed at which the vehicle speed Vown of the host vehicle 100 converges to the set vehicle speed Vset becomes greater than a predetermined speed, so that, as a result, acceleration or deceleration is performed in such a manner that the speed at which the vehicle speed Vown of the host vehicle 100 converges to the set vehicle speed Vset becomes greater than a predetermined speed.

[0095] In addition, in this example, although the vehicle driving support device 10 accelerates or decelerates the host vehicle 100 based on the set vehicle speed Vset when executing the normal constant speed control (first constant speed control), for example, it can also be configured so that the vehicle speed range (first vehicle speed range R1) including the set vehicle speed Vset is determined based on the set vehicle speed Vset and used as a reference for determining whether to accelerate or decelerate the host vehicle 100, when the vehicle speed Vown decreases and falls below the lower limit value Vlow1 of the first vehicle speed range R1, the host vehicle 100 is accelerated and the vehicle speed Vown is increased, and when the vehicle speed Vown increases and exceeds the upper limit value Vup1 of the first vehicle speed range R1, the host vehicle 100 is decelerated and the vehicle speed Vown is reduced. As a result, the average vehicle speed Vave (average value of the vehicle speed Vown) of the host vehicle 100 is controlled to be near the set vehicle speed Vset.

[0096] Energy-saving driving support control

[0097] On the other hand, when the energy-saving driving condition Ceco is satisfied while the driving support execution condition Cacc is satisfied, the vehicle driving support device 10 executes energy-saving driving support control. At this time, the vehicle driving support device 10 executes energy-saving driving support control according to the presence or absence of the preceding vehicle 200fr and the following vehicle 200rr.

[0098] Energy-saving constant speed control (2nd constant speed control)

[0099] When neither the preceding vehicle 200fr nor the following vehicle 200rr exists when the energy-saving travel support control is executed, the vehicle driving support device 10 executes the energy-saving constant speed control (second constant speed control) as the energy-saving travel support control.

[0100] When executing the energy-saving constant speed control (second constant speed control), the vehicle driving support device 10 determines a vehicle speed range (second vehicle speed range R2 ) including the set vehicle speed Vset based on the set vehicle speed Vset and uses it as a reference for determining whether to accelerate or decelerate the host vehicle 100 .

[0101] And, if Figure 3B As shown, when the vehicle speed Vown decreases and falls below the lower limit Vlow2 of the second vehicle speed range R2, the vehicle driving support device 10 accelerates the host vehicle 100 to increase the vehicle speed Vown, and when the vehicle speed Vown increases and exceeds the upper limit Vup2 of the second vehicle speed range R2, the vehicle driving support device 10 decelerates the host vehicle 100 to reduce the vehicle speed Vown. Thus, the average vehicle speed Vave (average value of the vehicle speed Vown) of the host vehicle 100 is controlled near the set vehicle speed Vset.

[0102] In this example, the second vehicle speed range R2 is set to a wider range than the first vehicle speed range R1. In addition, when the vehicle speed Vset is set to the same value, the upper limit value Vup2 of the second vehicle speed range R2 is set to a value greater than the upper limit value Vup1 of the first vehicle speed range R1, and the lower limit value Vlow2 of the second vehicle speed range R2 is set to a value smaller than the lower limit value Vlow1 of the first vehicle speed range R1.

[0103] In addition, in this example, when the vehicle driving assistance device 10 performs energy-saving constant speed control (second constant speed control), when accelerating the vehicle 100, the acceleration G of the vehicle 100 at which the energy efficiency of the drive device 21 outputting the driving force Pd becomes greater than the predetermined efficiency when taking into account the vehicle speed Vown of the vehicle 100 at that time is calculated as the required acceleration Greq.

[0104] Then, the vehicle driving support device 10 calculates the required driving force Pd_req for achieving the required acceleration Greq, and controls the operation of the drive device 21 in such a manner as to output the required driving force Pd_req to accelerate the host vehicle 100. Therefore, as described above, the vehicle driving support device 10 calculates the required acceleration Greq in such a manner that the energy efficiency of the drive device 21 when the drive device 21 outputs the driving force Pd becomes greater than a predetermined efficiency, so that, as a result, the host vehicle 100 is accelerated in such a manner that the energy efficiency of the drive device 21 when the drive device 21 outputs the driving force Pd becomes greater than a predetermined efficiency.

[0105] On the other hand, when executing the energy-saving constant speed control (second constant speed control) of this example, the vehicle driving support device 10 calculates the acceleration G at which the required driving force Pd_req becomes zero as the required acceleration Greq when decelerating the host vehicle 100 .

[0106] Then, the vehicle driving support device 10 calculates the required driving force Pd_req for achieving the required acceleration Greq, and decelerates the host vehicle 100 by controlling the operation of the drive device 21 in such a manner that the required driving force Pd_req is output from the drive device 21 (i.e., in such a manner that the driving force Pd output from the drive device 21 becomes zero). In other words, the vehicle driving support device 10 causes the host vehicle 100 to coast.

[0107] In addition, when the drive device 21 includes a motor, the vehicle driving support device 10 can also be configured to, when executing the energy-saving constant speed control (second constant speed control) of this example, when decelerating the vehicle 100, regenerate electric power by utilizing the running energy of the vehicle 100 to rotate the motor, thereby decelerating the vehicle 100.

[0108] Other energy-saving driving support controls

[0109] On the other hand, when the preceding vehicle 200fr exists but the following vehicle 200rr does not exist during the energy-saving travel support control, the vehicle driving support device 10 determines whether the preceding vehicle distance Dfr is longer than a predetermined preceding intermediate distance Dfr_mid, which is set to a distance shorter than the predetermined preceding vehicle determination distance Dfr_th.

[0110] 1st acceleration / deceleration control

[0111] When determining that the front inter-vehicle distance Dfr is longer than the predetermined front mid distance Dfr_mid, the vehicle driving support device 10 executes the first acceleration / deceleration control described below.

[0112] That is, when the vehicle driving support device 10 performs the first acceleration / deceleration control, it first determines whether the host vehicle 100 is approaching the leading vehicle 200fr at a faster speed. Specifically, the vehicle driving support device 10 determines whether the vehicle speed Vown of the host vehicle 100 is faster than the vehicle speed Vfr of the leading vehicle 200fr and whether the difference ΔVfr between their vehicle speeds is greater than a predetermined front approaching vehicle speed difference ΔVfr_a.

[0113] like Figure 4A As shown, when the vehicle driving support device 10 determines that the vehicle speed Vown of the host vehicle 100 is faster than the vehicle speed Vfr of the preceding vehicle 20fr and the difference ΔVfr between their vehicle speeds is greater than a predetermined preceding approaching vehicle speed difference ΔVfr_a ( Figure 4A At time t40), the host vehicle 100 is decelerated to reduce the vehicle speed Vown of the host vehicle 100.

[0114] At this time, as described above, the vehicle driving support device 10 controls the operation of the drive device 21 so that the host vehicle 100 coasts, thereby decelerating the host vehicle 100 .

[0115] On the other hand, the vehicle driving support device 10 determines whether the vehicle speed Vown of the host vehicle 100 is very slow and the host vehicle 100 is leaving the leading vehicle 200fr at a faster speed, when it is not determined that "the vehicle speed Vown of the host vehicle 100 is faster than the vehicle speed Vfr of the leading vehicle 200fr and the difference ΔVfr between their vehicle speeds is larger than the predetermined front approaching vehicle speed difference ΔVfr_a". Specifically, the vehicle driving support device 10 determines whether the vehicle speed Vown of the host vehicle 100 is lower than the lower limit value Vlow2 of the second vehicle speed range R2 and the vehicle speed Vown of the host vehicle 100 is slower than the vehicle speed Vfr of the leading vehicle 200fr and the difference ΔVfr between their vehicle speeds is larger than the predetermined front leaving vehicle speed difference ΔVfr_b.

[0116] The predetermined front departure vehicle speed difference ΔVfr_b may be the same value as or different from the predetermined front approaching vehicle speed difference ΔVfr_a.

[0117] like Figure 4B As shown, the vehicle driving support device 10 determines that the vehicle speed Vown of the host vehicle 100 is lower than the lower limit value Vlow2 of the second vehicle speed range R2, the vehicle speed Vown of the host vehicle 100 is slower than the vehicle speed Vfr of the preceding vehicle 200fr, and the difference ΔVfr between their vehicle speeds is greater than the predetermined leading departure vehicle speed difference ΔVfr_b ( Figure 4B At time t41), the host vehicle 100 is accelerated to increase the vehicle speed Vown of the host vehicle 100.

[0118] At this time, the vehicle driving support device 10 also calculates the acceleration G of the host vehicle 100 as the required acceleration Greq, which makes the energy efficiency of the drive device 21 greater than the predetermined efficiency when the drive device 21 outputs the drive force Pd in ​​consideration of the vehicle speed Vown of the host vehicle 100 at this time.

[0119] Then, the vehicle driving support device 10 calculates the required driving force Pd_req for achieving the required acceleration Greq, and accelerates the host vehicle 100 by controlling the operation of the drive device 21 so as to output the required driving force Pd_req.

[0120] On the other hand, the vehicle driving assistance device 10 continues to accelerate the vehicle 100 when it is accelerating, and continues to decelerate the vehicle 100 when it is decelerating, unless it is judged that "the vehicle speed Vown of the vehicle 100 is lower than the lower limit value Vlow2 of the second vehicle speed range R2 and the vehicle speed Vown of the vehicle 100 is slower than the vehicle speed Vfr of the leading vehicle 200fr and the difference ΔVfr between their vehicle speeds is greater than the predetermined front departure speed difference ΔVfr_b".

[0121] Second acceleration / deceleration control

[0122] Furthermore, when the vehicle driving support device 10 determines that the front inter-vehicle distance Dfr is equal to or smaller than the predetermined front mid distance Dfr_mid, the vehicle driving support device 10 executes the second acceleration / deceleration control described below.

[0123] When executing the second acceleration / deceleration control, the vehicle driving support device 10 first determines whether the front inter-vehicle distance Dfr is longer than a predetermined front short distance Dfr_short. The predetermined front short distance Dfr_short is set to a distance shorter than a predetermined front mid distance Dfr_mid.

[0124] like Figure 5 As shown, when the vehicle driving support device 10 determines that the front vehicle distance Dfr is longer than the predetermined front short distance Dfr_short ( Figure 5 Before time t50), the host vehicle 100 is decelerated to reduce the vehicle speed Vown of the host vehicle 100.

[0125] At this time, as described above, the vehicle driving support device 10 controls the operation of the drive device 21 so that the host vehicle 100 coasts, thereby decelerating the host vehicle 100 .

[0126] On the other hand, when the vehicle driving support device 10 determines that the front vehicle distance Dfr is less than or equal to the predetermined front short distance Dfr_short ( Figure 5 At time t50), the normal driving support control is executed. At this time, since the leading vehicle 200fr exists, the vehicle driving support device 10 executes the following driving control as the normal driving support control.

[0127] Only the following car exists

[0128] When the preceding vehicle 200fr does not exist but the following vehicle 200rr exists during the energy-saving travel support control, the vehicle driving support device 10 determines whether the rear vehicle distance Drr is longer than a predetermined rear short distance Drr_short set to a distance shorter than a predetermined following vehicle determination distance Drr_th.

[0129] 3rd acceleration and deceleration control

[0130] When determining that the rear inter-vehicle distance Drr is longer than the predetermined rear short distance Drr_short, the vehicle driving support device 10 executes the third acceleration / deceleration control described below.

[0131] That is, when the vehicle driving support device 10 performs the third acceleration / deceleration control, it first determines whether the vehicle 200rr following the host vehicle 100 is approaching the host vehicle 100 at a faster speed and whether the vehicle speed Vown of the host vehicle 100 is allowed to increase. Specifically, the vehicle driving support device 10 determines whether the vehicle speed Vown of the host vehicle 100 is slower than the vehicle speed Vrr of the following vehicle 200rr and the difference ΔVrr between their vehicle speeds is greater than the predetermined rear approaching vehicle speed difference ΔVrr_a and the vehicle speed Vown of the host vehicle 100 is lower than the upper limit value Vup2 of the second vehicle speed range R2.

[0132] like Fig. 6A As shown, the vehicle driving support device 10 determines that the vehicle speed Vown of the host vehicle 100 is slower than the vehicle speed Vrr of the following vehicle 200rr, and the difference ΔVrr between their vehicle speeds is larger than the predetermined rear approaching vehicle speed difference ΔVrr_a, and the vehicle speed Vown of the host vehicle 100 is lower than the upper limit value Vup2 of the second vehicle speed range R2 ( Fig. 6A At time t60), the host vehicle 100 is accelerated to increase the vehicle speed Vown of the host vehicle 100.

[0133] At this time, the vehicle driving support device 10 also calculates the acceleration G of the host vehicle 100 as the required acceleration Greq, which makes the energy efficiency of the drive device 21 greater than the predetermined efficiency when the drive device 21 outputs the drive force Pd in ​​consideration of the vehicle speed Vown of the host vehicle 100 at this time.

[0134] Then, the vehicle driving support device 10 calculates the required driving force Pd_req for achieving the required acceleration Greq, and accelerates the host vehicle 100 by controlling the operation of the drive device 21 so as to output the required driving force Pd_req.

[0135] On the other hand, the vehicle driving assistance device 10 continues to accelerate the vehicle 100 when it is accelerating, and continues to decelerate the vehicle 100 when it is decelerating, unless it is judged that "the vehicle speed Vown of the vehicle 100 is slower than the vehicle speed Vrr of the following vehicle 200rr and the difference ΔVrr between their vehicle speeds is larger than the predetermined rear approaching vehicle speed difference ΔVrr_a and the vehicle speed Vown of the vehicle 100 is lower than the upper limit value Vup2 of the second vehicle speed range R2".

[0136] 4th Acceleration and Deceleration Control

[0137] Furthermore, when the vehicle driving support device 10 determines that the rear inter-vehicle distance Drr is equal to or smaller than the predetermined rear short distance Drr_short, the vehicle driving support device 10 executes the fourth acceleration / deceleration control described below.

[0138] That is, when executing the fourth acceleration / deceleration control, the vehicle driving support device 10 first determines whether the vehicle speed Vown of the host vehicle 100 is lower than the upper limit value Vup2 of the second vehicle speed range R2.

[0139] like Figure 6B As shown, when the vehicle driving support device 10 determines that the vehicle speed Vown of the host vehicle 100 is lower than the upper limit value Vup2 of the second vehicle speed range R2 ( Figure 6B Before time t61), the host vehicle 100 is accelerated to increase the vehicle speed Vown of the host vehicle 100.

[0140] At this time, the vehicle driving support device 10 also calculates the acceleration G of the host vehicle 100 as the required acceleration Greq, which makes the energy efficiency of the drive device 21 greater than the predetermined efficiency when the drive device 21 outputs the drive force Pd in ​​consideration of the vehicle speed Vown of the host vehicle 100 at this time.

[0141] Then, the vehicle driving support device 10 calculates the required driving force Pd_req for achieving the required acceleration Greq, and accelerates the host vehicle 100 by controlling the operation of the drive device 21 so as to output the required driving force Pd_req.

[0142] On the other hand, when the vehicle driving support device 10 determines that the vehicle speed Vown of the host vehicle 100 is equal to or greater than the upper limit value Vup2 of the second vehicle speed range R2 ( Figure 6B At time t61), the normal driving support control is executed. At this time, since there is no preceding vehicle 200fr, the vehicle driving support device 10 executes the normal constant speed control (first constant speed control) as the normal driving support control.

[0143] There are leading and following vehicles

[0144] When the driving support execution condition Cacc is satisfied, even if the energy-saving driving condition Ceco is satisfied, the vehicle driving support device 10 performs the normal driving support control if there are the preceding vehicle 200fr and the following vehicle 200rr. At this time, since there is the preceding vehicle 200fr, the vehicle driving support device 10 performs the following driving control.

[0145] Effect

[0146] The energy efficiency E when the drive device 21 outputs the driving force has a characteristic that it becomes the highest (reaches a peak value) when the driving force Pd output by the drive device 21 is a specific value. For example, when the drive device 21 includes an internal combustion engine and a motor, as shown in FIG. Figure 7 As shown, the energy efficiency Eeng (especially, fuel economy) when the internal combustion engine outputs driving force is highest when the driving force Pd_eng output by the internal combustion engine is a certain value Pd_a, and the energy efficiency Emotor (especially, electric power economy) when the motor outputs driving force is highest when the driving force Pd_motor output by the motor is a value Pd_b smaller than the above value Pd_a.

[0147] Therefore, although the operation of the drive device 21 is controlled in order to output the driving force from the drive device 21 , the greater the degree of freedom in controlling the drive device 21 , the greater the ability to operate the drive device 21 with higher energy efficiency.

[0148] Generally, when the vehicle speed is controlled to a certain specific speed, when the vehicle speed is controlled while allowing a wider range of speed changes, the degree of freedom of control when controlling the operation of the drive device in order to output the driving force (vehicle driving force) applied to the vehicle increases. As a result, it is possible to select a control with higher energy efficiency as the control of the drive device. According to the vehicle driving support device 10, a normal constant speed control (first constant speed control) with a set vehicle speed Vset as a reference and a narrow range of allowed speed changes, and an energy-saving constant speed control (second constant speed control) with a second vehicle speed range R2 as a reference and a wider range of allowed speed changes are prepared as driving support controls, and the energy-saving constant speed control is performed according to the driving state of the vehicle 100. Therefore, the vehicle 100 can be driven while the vehicle speed Vown of the vehicle 100 is controlled near the set vehicle speed Vset with higher energy efficiency.

[0149] Specific operation of vehicle driving support device

[0150] Next, the 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 following operation every time a predetermined operation time has elapsed. Figure 8 Therefore, when the predetermined timing is reached, the CPU starts Figure 8 The process starts at step 800 and proceeds to step 805 to determine whether the driving support execution condition Cacc is satisfied.

[0151] When the CPU makes a “Yes” determination at step 805 , the CPU advances the process to step 810 to determine whether the energy-saving travel condition Ceco is satisfied.

[0152] When the CPU makes a “YES” determination at step 810 , the CPU advances the process to step 815 to determine whether the rear vehicle distance Drr is longer than a predetermined following vehicle determination distance Drr_th.

[0153] If the CPU determines "yes" in step 815, the process proceeds to step 820 to execute Fig. 9 Therefore, when the CPU advances the processing to step 820, Fig. 9 The process starts at step 900 and proceeds to step 905 to determine whether the front vehicle distance Dfr is longer than a predetermined preceding vehicle determination distance Dfr_th.

[0154] If the CPU determines "yes" in step 905, the process proceeds to step 910, and the CPU executes Fig.10 Therefore, when the CPU advances the processing to step 910, the energy-saving constant speed control (second constant speed control) is performed according to the routine shown in FIG. Fig.10 The process starts at step 1000 and proceeds to step 1005 to determine whether the vehicle speed Vown of the host vehicle 100 is faster than the upper limit value Vup2 of the second vehicle speed range R2.

[0155] When the CPU makes a “YES” determination at step 1005 , the CPU proceeds to step 1010 , and executes deceleration control to decelerate the host vehicle 100 .

[0156] In this example, the deceleration control executed in step 1010 and the steps described later is a control to decelerate the host vehicle 100 by controlling the operation of the drive device 21 so that the host vehicle 100 coasts. Therefore, the deceleration control can also be called coasting control.

[0157] Thereafter, the CPU causes the processing to proceed to steps 1095 and Fig. 9 Step 995 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0158] On the other hand, when the CPU makes a “No” determination in step 1005 , the CPU advances the process to step 1015 to determine whether the vehicle speed Vown of the host vehicle 100 is lower than the lower limit value Vlow2 of the second vehicle speed range R2 .

[0159] When the CPU makes a “YES” determination at step 1015 , the CPU proceeds to step 1020 , and executes acceleration control to accelerate the host vehicle 100 .

[0160] In this example, the acceleration control performed in step 1020 and the subsequent steps is the following control: the acceleration G of the vehicle 100 at which the energy efficiency of the drive device 21 outputs the driving force Pd while taking into account the vehicle speed Vown of the vehicle 100 at this time becomes greater than a predetermined efficiency is calculated as the required acceleration Greq, and then the vehicle driving assistance device 10 calculates the required driving force Pd_req for achieving the required acceleration Greq, and accelerates the vehicle 100 by controlling the operation of the drive device 21 in such a manner as to output the required driving force Pd_req.

[0161] Thereafter, the CPU causes the processing to proceed to steps 1095 and Fig. 9 Step 995 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0162] On the other hand, if the CPU makes a "No" determination in step 1015, the processing proceeds to steps 1095 and 1096. Fig. 9 Step 995 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0163] In addition, the CPU Fig. 9 If it is determined as "NO" in step 905, the process proceeds to step 915 to determine whether the front vehicle distance Dfr is longer than a predetermined front mid distance Dfr_mid.

[0164] If the CPU determines "yes" in step 915, the process proceeds to step 920, and the CPU executes Fig.11 Therefore, when the CPU advances the processing to step 920, the first acceleration / deceleration control is performed by the routine shown in FIG. Fig.11 The process starts at step 1100 and proceeds to step 1105 to determine whether the vehicle speed Vown of the host vehicle 100 is faster than the vehicle speed Vfr of the preceding vehicle 200fr and whether the difference ΔVfr between their vehicle speeds is greater than a predetermined preceding approaching vehicle speed difference ΔVfr_a.

[0165] When the CPU makes a “YES” determination at step 1105 , the CPU proceeds to step 1110 , and executes deceleration control to decelerate the host vehicle 100 .

[0166] Thereafter, the CPU causes the processing to proceed to steps 1195 and Fig. 9 Step 995 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0167] On the other hand, if the CPU determines as "No" in step 1105, it proceeds to step 1115 to determine whether the vehicle speed Vown of the vehicle 100 is slower than the lower limit value Vlow2 of the second vehicle speed range R2 and the vehicle speed Vown of the vehicle 100 is slower than the vehicle speed Vfr of the leading vehicle 200fr and the difference ΔVfr between their vehicle speeds is greater than the predetermined front departure speed difference ΔVfr_b.

[0168] When the CPU makes a “YES” determination at step 1115 , the CPU proceeds to step 1120 , and executes acceleration control to accelerate the host vehicle 100 .

[0169] Thereafter, the CPU causes the processing to proceed to steps 1195 and Fig. 9 Step 995 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0170] On the other hand, if the CPU makes a "No" determination in step 1115, the CPU causes the processing to proceed to steps 1195 and 1196. Fig. 9 Step 995 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0171] In addition, the CPU Fig. 9 If the judgment is "No" in step 915, the process proceeds to step 925, and the Fig.12 Therefore, when the CPU advances the processing to step 925, the second acceleration / deceleration control is performed by the routine shown in FIG. Fig.12 The process starts at step 1200 and proceeds to step 1205 to determine whether the front vehicle distance Dfr is longer than a predetermined front short distance Dfr_short.

[0172] When the CPU makes a “YES” determination at step 1205 , the CPU proceeds to step 1210 , and executes deceleration control to decelerate the host vehicle 100 .

[0173] Afterwards, the CPU goes through steps 1295 and Fig. 9 Step 995 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0174] On the other hand, when the CPU makes a "NO" determination at step 1205, the CPU advances the process to step 1215 to execute the follow-up travel control.

[0175] Thereafter, the CPU causes the processing to proceed to steps 1295 and Fig. 9 Step 995 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0176] In addition, the CPU Figure 8 If the determination at step 815 is "NO", the process proceeds to step 825 to determine whether the front vehicle distance Dfr is longer than a predetermined preceding vehicle determination distance Dfr_th.

[0177] If the CPU determines "yes" in step 825, the process proceeds to step 830, and the CPU executes Fig.13 Therefore, when the CPU advances the processing to step 830, Fig.13 The process starts at step 1300 and proceeds to step 1305 to determine whether the rear vehicle distance Drr is longer than a predetermined rear short distance Drr_short.

[0178] If the CPU determines "yes" in step 1305, the process proceeds to step 1310, and the CPU executes Fig.14 Therefore, when the CPU advances the processing to step 1310, the third acceleration / deceleration control is performed by the routine shown in FIG. Fig.14 The processing starts at step 1400 and proceeds to step 1405 to determine whether the vehicle speed Vown of the host vehicle 100 is lower than the upper limit value Vup2 of the second vehicle speed range R2 and the vehicle speed Vown of the host vehicle 100 is slower than the vehicle speed Vrr of the following vehicle 200rr and the difference ΔVrr between their vehicle speeds is greater than the predetermined rear approaching vehicle speed difference ΔVrr_a.

[0179] When the CPU makes a “YES” determination at step 1405 , the CPU proceeds with the process to step 1410 , and executes acceleration control to accelerate the host vehicle 100 .

[0180] Thereafter, the CPU causes the processing to proceed to steps 1495 and Fig.13 Step 1395 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0181] On the other hand, if the CPU makes a "No" determination in step 1405, the processing proceeds to steps 1495 and 1496. Fig.13 Step 1395 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0182] If the CPU determines "No" in step 1305, the process proceeds to step 1315, and the CPU executes Fig.15 Therefore, when the CPU advances the processing to step 1315, it performs the fourth acceleration and deceleration control. Fig.15 The process starts at step 1500 and proceeds to step 1505 to determine whether the vehicle speed Vown of the host vehicle 100 is lower than the upper limit value Vup2 of the second vehicle speed range R2.

[0183] When the CPU makes a “YES” determination at step 1505 , the CPU proceeds with the process to step 1510 , and executes acceleration control to accelerate the host vehicle 100 .

[0184] Thereafter, the CPU causes the processing to proceed to steps 1595 and Fig.13 Step 1395 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0185] On the other hand, when the CPU makes a "NO" determination at step 1505, the CPU advances the process to step 1515 to execute normal constant speed control (first constant speed control).

[0186] Thereafter, the CPU causes the processing to proceed to steps 1595 and Fig.13 Step 1395 proceeds to Figure 8 Step 895 temporarily ends this routine.

[0187] In addition, the CPU Figure 8 If the determination in step 825 is "No", the processing proceeds to step 835 and the following driving control is executed.

[0188] Thereafter, the CPU advances the processing to step 895 and temporarily ends this routine.

[0189] If the CPU determines "No" in step 810, the process proceeds to step 840, and the CPU executes Fig.16 Therefore, when the CPU advances the processing to step 840, Fig.16 The process starts at step 1600 and proceeds to step 1605 to determine whether the front vehicle distance Dfr is longer than a predetermined preceding vehicle determination distance Dfr_th.

[0190] When the CPU makes a “YES” determination at step 1605 , the CPU proceeds with the process to step 1610 to execute follow-up travel control.

[0191] After that, the CPU advances the processing to step 1695. Figure 8 Step 895 temporarily ends this routine.

[0192] On the other hand, when the CPU makes a "NO" determination at step 1605, the CPU advances the process to step 1615 to execute normal constant speed control (first constant speed control).

[0193] After that, the CPU advances the processing to step 1695. Figure 8 Step 895 temporarily ends this routine.

[0194] In addition, the CPU Figure 8 If the determination in step 805 is "No", the processing proceeds to step 895 and temporarily ends this routine.

[0195] The above is the specific operation of the vehicle driving support device 10 .

[0196] 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.

[0197] For example, the vehicle driving support device 10, when executing the energy-saving driving support control and there is a leading vehicle 200fr but there is no following vehicle 200rr, executes the first acceleration / deceleration control or the second acceleration / deceleration control according to whether the front vehicle distance Dfr is longer than the predetermined front middle distance Dfr_mid. However, it can also be configured such that when there is a leading vehicle 200fr but there is no following vehicle 200rr during the execution of the energy-saving driving support control, the first acceleration / deceleration control or the second acceleration / deceleration control is executed regardless of whether the front vehicle distance Dfr is longer than the predetermined front middle distance Dfr_mid.

[0198] In addition, the vehicle driving support device 10, when there is no leading vehicle 200fr but there is a following vehicle 200rr during the execution of energy-saving driving support control, performs the third acceleration / deceleration control or the fourth acceleration / deceleration control according to whether the rear vehicle distance Drr is longer than the predetermined rear short distance Drr_short. However, it can also be configured that when there is no leading vehicle 200fr but there is a following vehicle 200rr during the execution of energy-saving driving support control, the third acceleration / deceleration control or the fourth acceleration / deceleration control is performed regardless of whether the rear vehicle distance Drr is longer than the predetermined rear short distance Drr_short.

Claims

1. A vehicle driving support device comprising a controller and a detection device, The controller performs driving support control for automatically controlling the acceleration of the host vehicle so that the host vehicle automatically drives. The detection device detects a preceding vehicle traveling in the same lane as the host vehicle and within a predetermined preceding vehicle determination distance in front of the host vehicle, The driving support control includes a first constant speed control and a second constant speed control, wherein the first constant speed control is a control for automatically controlling the acceleration of the host vehicle with a first speed range including the set speed as a reference in order to maintain the vehicle speed of the host vehicle at the set speed, and the second constant speed control is a control for automatically controlling the acceleration of the host vehicle with a second speed range including the set speed as a reference in order to maintain the vehicle speed of the host vehicle at the set speed, The second vehicle speed range is set to be wider than the first vehicle speed range. The controller is configured to switch the driving support control between the first constant speed control and the second constant speed control according to the driving state of the host vehicle, The controller is configured as follows: When the second constant speed control is requested to be executed and the detection device does not detect the preceding vehicle, the second constant speed control is executed; When the second constant speed control is requested to be executed and the detection device detects the preceding vehicle, (i) when the front inter-vehicle distance between the preceding vehicle and the host vehicle is longer than a predetermined front intermediate distance that is shorter than the predetermined preceding vehicle determination distance, executing a first acceleration / deceleration control as the second constant speed control, (ii) When the front vehicle distance is equal to or less than the predetermined front intermediate distance, a second acceleration / deceleration control different from the first acceleration / deceleration control is executed as the second constant speed control.

2. The vehicle driving support device according to claim 1, The detection device is configured to detect a following vehicle traveling in the same lane as the host vehicle and within a predetermined following vehicle determination distance behind the host vehicle, The controller is configured to execute the first constant speed control when there is no request to execute the second constant speed control when neither the preceding vehicle nor the following vehicle exists, The controller is configured to execute the second constant speed control when execution of the second constant speed control is requested when neither the preceding vehicle nor the following vehicle exists.

3. The vehicle driving support device according to claim 1 or 2, The second constant speed control includes a deceleration control for reducing the vehicle speed of the host vehicle and an acceleration control for increasing the vehicle speed of the host vehicle. The controller is configured to, when executing the second constant speed control, execute the deceleration control when the vehicle speed increases and reaches the upper limit value of the second vehicle speed range, and execute the acceleration control when the vehicle speed decreases and reaches the lower limit value of the second vehicle speed range.

4. The vehicle driving support device according to claim 1, The detection device is configured to detect a following vehicle traveling in the same lane as the host vehicle and within a predetermined following vehicle determination distance behind the host vehicle, The controller is configured to execute the first constant speed control when there is no request to execute the second constant speed control when neither the preceding vehicle nor the following vehicle exists, The controller is configured to execute the second constant speed control when execution of the second constant speed control is requested when neither the preceding vehicle nor the following vehicle exists, The controller is configured to execute a deceleration control for reducing the speed of the host vehicle when, in the case where the preceding vehicle exists and the following vehicle does not exist, the second constant speed control is required to be executed, the front vehicle distance is longer than the predetermined front intermediate distance, the speed of the host vehicle is faster than the speed of the preceding vehicle, and the difference between the speed of the host vehicle and the speed of the preceding vehicle is greater than a predetermined front approaching vehicle speed difference, The controller is configured to perform acceleration control for increasing the speed of the host vehicle when, in the case where the leading vehicle exists but the following vehicle does not exist, execution of the second constant speed control is required, the front vehicle distance is longer than the predetermined front middle distance, the speed of the host vehicle is slower than the speed of the leading vehicle, the difference between the speed of the host vehicle and the speed of the leading vehicle is greater than a predetermined front departure speed difference, and the speed of the host vehicle is slower than the lower limit of the second speed range.

5. The vehicle driving support device according to claim 1, The detection device is configured to detect a following vehicle traveling in the same lane as the host vehicle and within a predetermined following vehicle determination distance behind the host vehicle, The driving support control includes a following driving control, wherein the following driving control automatically controls the acceleration of the host vehicle so as to maintain the preceding vehicle distance at a set preceding vehicle distance. The controller is configured to execute the first constant speed control when there is no request to execute the second constant speed control when neither the preceding vehicle nor the following vehicle exists, The controller is configured to execute the second constant speed control when execution of the second constant speed control is requested when neither the preceding vehicle nor the following vehicle exists, The controller is configured to execute a deceleration control for reducing the speed of the host vehicle when, in the case where the preceding vehicle exists and the following vehicle does not exist, the second constant speed control is requested to be executed, and the front vehicle distance is longer than the predetermined front intermediate distance, the speed of the host vehicle is faster than the speed of the preceding vehicle, and the difference between the speed of the host vehicle and the speed of the preceding vehicle is greater than a predetermined front approaching vehicle speed difference, The controller is configured to execute the deceleration control when the preceding vehicle exists and the following vehicle does not exist and the second constant speed control is required to be executed and the front vehicle distance is less than the predetermined front middle distance and longer than a predetermined front short distance that is shorter than the predetermined front middle distance, The controller is configured to execute the following travel control even when execution of the second constant speed control is requested when the preceding vehicle is present and the following vehicle is not present and the front vehicle distance is equal to or less than the predetermined front short distance.

6. The vehicle driving support device according to claim 1, The detection device is configured to detect a following vehicle traveling in the same lane as the host vehicle and within a predetermined following vehicle determination distance behind the host vehicle, The controller is configured to execute the first constant speed control when there is no request to execute the second constant speed control when neither the preceding vehicle nor the following vehicle exists, The controller is configured to execute the second constant speed control when execution of the second constant speed control is requested when neither the preceding vehicle nor the following vehicle exists, The controller is configured to, when the preceding vehicle does not exist and the following vehicle exists, execute acceleration control for increasing the vehicle speed of the host vehicle when the second constant speed control is required to be executed and the rear vehicle distance between the host vehicle and the following vehicle is longer than a predetermined rear approach distance that is shorter than the predetermined following vehicle determination distance and the vehicle speed of the host vehicle is slower than the vehicle speed of the following vehicle and the vehicle speed difference between the vehicle speed of the host vehicle and the following vehicle is greater than a predetermined rear approach vehicle speed difference, The controller is configured to execute the acceleration control when the preceding vehicle does not exist and the following vehicle exists, and when the second constant speed control is required to be executed, and the rear vehicle distance is less than the predetermined rear close distance and the vehicle speed of the host vehicle is slower than the upper limit of the second vehicle speed range, The controller is configured to execute the first constant speed control even when execution of the second constant speed control is requested, when the preceding vehicle does not exist and the following vehicle exists, and when the rear vehicle distance is less than the predetermined rear close distance and the vehicle speed of the host vehicle is greater than the upper limit value of the second vehicle speed range.

7. The vehicle driving support device according to claim 1, The driving support control includes a following driving control, wherein the following driving control automatically controls the acceleration of the host vehicle so as to maintain the preceding vehicle distance at a set preceding vehicle distance. The controller is configured to execute the following travel control when there is no request to execute the second constant speed control when the preceding vehicle is present.

8. The vehicle driving support device according to any one of claims 1 to 2 and 4 to 7, A driving device is further provided, the driving device being configured to output a driving force applied to the host vehicle, The controller is configured to accelerate and decelerate the host vehicle so that the speed at which the vehicle speed converges to the set vehicle speed becomes equal to or greater than a predetermined speed when executing the first constant speed control. The controller is configured to accelerate and decelerate the host vehicle so that the energy efficiency of the drive device when the drive device outputs the drive force becomes equal to or higher than a predetermined efficiency when executing the second constant speed control.

9. The vehicle driving support device according to claim 3, A driving device is further provided, the driving device being configured to output a driving force applied to the host vehicle, The controller is configured to accelerate and decelerate the host vehicle so that the speed at which the vehicle speed converges to the set vehicle speed becomes equal to or greater than a predetermined speed when executing the first constant speed control. The controller is configured to accelerate and decelerate the host vehicle so that the energy efficiency of the drive device when the drive device outputs the drive force becomes equal to or higher than a predetermined efficiency when executing the second constant speed control.

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