阅读说明：本技术 车辆的控制装置、车辆的控制方法及存储介质 (Vehicle control device, vehicle control method, and storage medium ) 是由 宫冈史滋 于 2021-03-04 设计创作，主要内容包括：本发明提供一种车辆的控制装置、车辆的控制方法及存储介质,其当在自动驾驶过程中预测到要求驱动力的增加时,可减低由降档引起的振动、噪音及变速冲击。当在实施自动驾驶控制的过程中预测到要求驱动力的增加时,搭载有自动变速器(TM)的能够进行自动驾驶控制的车辆的控制装置(100)在要求驱动力的增加时机之前,维持或者减少所述车辆的车速同时在要求驱动力的增加时机之前的待机期间内使所述发动机的转速上升,根据发动机转速的上升使发动机的扭矩下降,使自动变速器的变速档向下方换档。(The invention provides a control device of a vehicle, a control method of the vehicle and a storage medium, which can reduce vibration, noise and shift shock caused by downshift when the increase of the required driving force is predicted in the automatic driving process. When an increase in the required driving force is predicted during execution of the automatic driving control, a control device (100) of a vehicle equipped with an automatic Transmission (TM) and capable of performing the automatic driving control increases the rotation speed of the engine during a standby period before the increase timing of the required driving force while maintaining or reducing the vehicle speed of the vehicle before the increase timing of the required driving force, and shifts the gear of the automatic transmission downward by decreasing the torque of the engine according to the increase in the rotation speed of the engine.)

1. A control device for a vehicle, which is equipped with an automatic transmission and is capable of performing automatic driving control for automatically controlling at least acceleration and deceleration of the vehicle,

maintaining or reducing a vehicle speed of the vehicle prior to an increase timing of the required driving force when an increase in the required driving force is predicted in implementing the automatic driving control,

while increasing the rotational speed of the engine during a standby period before the timing of increase in the required driving force,

the torque of the engine is reduced in accordance with the increase in the engine speed, and the gear stage of the automatic transmission is shifted downward.

2. The control device for a vehicle according to claim 1, wherein the increase in the engine speed is performed during a period shorter than the standby period and longer than a normal shift time.

3. The control device for a vehicle according to claim 1, wherein when the increase in the required driving force is suspended, the rotation speed of the engine increased so far is reduced by shifting the shift stage of the automatic transmission upward.

4. The control device for a vehicle according to claim 3, wherein the shift stage of the automatic transmission is shifted upward so that a decrease in the rotation speed of the engine becomes a smaller amount of change than that in an increase.

5. The vehicle control device according to claim 1, wherein the required driving force needs to be increased at the time of passing, and when there is a possibility of collision with a vehicle ahead or behind a passing lane when the passing is performed, the passing control is made to stand by until the passing is possible.

6. A control method for a vehicle, which is equipped with an automatic transmission and is capable of automatically controlling at least acceleration and deceleration of the vehicle, is characterized in that,

maintaining or reducing a vehicle speed of the vehicle prior to an increase timing of the required driving force when an increase in the required driving force is predicted in implementing the automatic driving control,

while increasing the rotational speed of the engine during a standby period before the timing of increase in the required driving force,

the torque of the engine is reduced in accordance with the increase in the engine speed, and the gear stage of the automatic transmission is shifted downward.

7. The control method of a vehicle according to claim 6, characterized in that the increase in the engine speed is performed during a period shorter than the standby period and longer than a normal shift time.

8. The method of controlling a vehicle according to claim 6, characterized in that when the increase in the required driving force is suspended, the rotational speed of the engine that has been increased so far is reduced by shifting a gear position of the automatic transmission upward.

9. The method of controlling a vehicle according to claim 8, wherein the shift stage of the automatic transmission is shifted upward so that a decrease in the rotation speed of the engine becomes a smaller amount of change than that in an increase.

10. The method according to claim 6, wherein the required driving force needs to be increased at the time of passing, and when there is a possibility of collision with a vehicle ahead or behind a passing lane when the passing is performed, the passing control is made to stand by until the passing is possible.

11. A storage medium storing a program for causing a processor to function as a control device of a vehicle equipped with an automatic transmission and capable of automatic driving control for automatically controlling at least acceleration and deceleration of the vehicle, the program being characterized in that the processor implements:

maintaining or reducing a vehicle speed of the vehicle prior to an increase timing of the required driving force when an increase in the required driving force is predicted in implementing the automatic driving control,

while increasing the rotational speed of the engine during a standby period before the timing of increase in the required driving force,

the torque of the engine is reduced in accordance with the increase in the engine speed, and the gear stage of the automatic transmission is shifted downward.

Technical Field

The present invention relates to a vehicle equipped with an automatic transmission (hereinafter referred to as an automatic transmission vehicle), and more particularly to a control technique of an automatic transmission vehicle during automatic driving, a vehicle control device, a vehicle control method, and a storage medium.

Background

In a vehicle capable of automatic driving, by recognizing the traveling state of the vehicle and the surrounding situation, the next action can be calculated in advance and executed. For example, when the autonomous vehicle is overtaking, it is determined whether or not overtaking is to be performed based on the surrounding situation, and when overtaking is to be performed, control necessary for overtaking is performed by acceleration calculation or the like.

According to the travel control device disclosed in patent document 1, when the autonomous vehicle performs overtaking travel, it is determined whether overtaking is to be performed or not based on the travel state of the rear vehicle, and when the rear vehicle approaches, it is calculated in advance what degree of acceleration travel is required, and appropriate travel control is performed.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent application laid-open No. 2019-119303

Disclosure of Invention

[ problems to be solved by the invention ]

In an automatic transmission vehicle, a downshift may be required when the required driving force is increased during automatic driving, when there is a downhill, or the like. In the case where acceleration for overtaking is required as described above, a large drive torque is required, and therefore downshifting can be performed. In addition, in order to keep the vehicle speed constant when descending a slope, a downshift may be performed. However, when such a shift is performed in a short time, the driving torque increases rapidly, and the so-called shift shock increases. Such a shift shock gives an uncomfortable feeling to the occupant, and may deteriorate ride comfort. Further, the engine speed may be greatly changed by the downshift, and the large change in the sound may give an uncomfortable feeling to the occupant.

In general, in the automatic driving control, the occupant does not drive the vehicle by himself or herself, and therefore the occupant is more sensitive to discomfort such as vibration, noise, or shift shock of the vehicle caused by the operation of the engine or the transmission at the time of acceleration or deceleration. Therefore, particularly in the case of automatic driving, measures for reducing Vibration, Noise reduction performance (Noise Vibration (NV) reduction performance) and shift shock are required to be higher than those in the case of manual driving.

An object of the present invention is to provide a control device of a vehicle, a control method of a vehicle, and a storage medium that can reduce vibration, noise, and shift shock caused by a downshift when an increase in required driving force is predicted during automatic driving.

[ means for solving problems ]

A control device for a vehicle according to a first embodiment of the present invention is a control device 100 for a vehicle 1 equipped with an automatic transmission and capable of performing automatic driving control for automatically controlling at least acceleration and deceleration of the vehicle 1, wherein when an increase in required driving force is predicted while the automatic driving control is being performed, the vehicle speed of the vehicle 1 is maintained or reduced before an increase timing of the required driving force, the engine speed is increased during a standby period before the increase timing of the required driving force, the engine torque is decreased in accordance with the increase in the engine speed, and the shift stage of the automatic transmission is shifted downward.

A control method of a vehicle according to a second embodiment of the present invention is a control method of a vehicle 1 in which an automatic transmission is mounted and at least acceleration and deceleration of the vehicle 1 can be automatically controlled, wherein when an increase in required driving force is predicted while the automatic driving control is being performed, the vehicle speed of the vehicle 1 is maintained or reduced before the increase timing of the required driving force, the rotation speed of the engine is increased during a standby period before the increase timing of the required driving force, and the torque of the engine is decreased in accordance with the increase in the rotation speed of the engine, so that the gear stage of the automatic transmission is shifted downward.

A storage medium according to a third embodiment of the present invention stores a program that causes a processor to function as a control device 100 of a vehicle 1 that is equipped with an automatic transmission and that is capable of performing automatic driving control that automatically controls at least acceleration and deceleration of the vehicle 1, and the program causes the processor to function as: when an increase in the required driving force is predicted while the automatic driving control is being executed, the vehicle speed of the vehicle 1 is maintained or reduced before the increase timing of the required driving force, the engine speed is increased during a standby period before the increase timing of the required driving force, the engine torque is decreased in accordance with the increase in the engine speed, and the shift stage of the automatic transmission is shifted downward.

Accordingly, the engine speed is increased, the engine torque is decreased, and the shift stage is downshifted during the standby period, so that a sudden increase in the engine speed and a feeling of incongruity due to a shift shock when the driving force is actually increased can be greatly alleviated.

Preferably, the increase in the engine speed is performed during a period shorter than the standby period and longer than a normal shift time. As a result, the engine speed gradually increases during the standby for passing control, and thus the passenger is less likely to notice the increase.

When the increase in the required driving force is suspended, the speed stage of the automatic transmission is shifted upward to reduce the number of revolutions of the engine that has been increased so far. In this case, it is preferable that the shift of the automatic transmission from the gear position to the upper side is performed so that the rotation speed of the engine decreases by a smaller amount of change than that in the case of the increase. When the increase in the required driving force is suspended, the engine speed gradually decreases by a smaller amount than when it increases, and therefore it is difficult for the occupant to notice.

It is desirable that the required driving force be increased at the time of passing, and the passing control be made to stand by until the passing is possible when there is a possibility of collision with a vehicle ahead or behind a passing lane when the passing is performed. Accordingly, the engine speed is increased, the engine torque is decreased, and the shift stage is downshifted during the standby period, so that the sense of incongruity due to the rapid increase in the engine speed and the shift shock when overtaking is actually performed can be greatly alleviated.

[ Effect of the invention ]

As described above, according to the present invention, it is possible to reduce vibration, noise, and shift shock caused by downshifting when an increase in required driving force is predicted during automatic driving.

Drawings

Fig. 1 is a functional configuration diagram related to automatic driving control in a vehicle control device according to an embodiment of the present invention.

Fig. 2 is a block diagram schematically showing an example of the internal structure of an automatic transmission vehicle (multi-speed transmission vehicle) using a control device according to a first embodiment of the present invention.

Fig. 3 is a schematic diagram showing a sequence of the overtaking travel for explaining the control method of the automatic transmission vehicle shown in fig. 2.

Fig. 4 is a flowchart showing control performed during the acceleration standby and the acceleration execution based on the control method of the automatic transmission vehicle shown in fig. 2.

Fig. 5 (a) to 5 (f) are waveform diagrams illustrating control states of the first gear shift during the acceleration standby time and the acceleration execution time based on the control method of the automatic transmission vehicle shown in fig. 2.

Fig. 6 (a) to 6 (f) are waveform diagrams illustrating control states of multi-stage shift during the time of the acceleration standby and the acceleration execution based on the control method of the automatic transmission vehicle shown in fig. 2.

Fig. 7 is a flowchart showing the downhill prediction and the control during the downhill control based on the control method of the automatic transmission vehicle shown in fig. 2.

Fig. 8 (a) to 8 (e) are waveform diagrams illustrating control states in downhill prediction and downhill control based on the control method of the automatic transmission vehicle shown in fig. 2.

Fig. 9 is a block diagram schematically showing an example of the internal structure of an automatic transmission vehicle (continuously variable transmission vehicle) using a control device according to a first embodiment of the present invention.

Fig. 10 (a) to 10 (f) are flowcharts showing control during the acceleration standby and acceleration execution based on the control method of the automatic transmission vehicle shown in fig. 9.

Fig. 11 (a) to 11 (f) are waveform diagrams illustrating control states at the time of acceleration suspension based on the control method of the automatic transmission vehicle shown in fig. 9.

Fig. 12 (a) to 12 (f) are waveform diagrams showing control states at the time of an acceleration standby and at the time of acceleration execution for explaining a Rubber belt (Rubber Band) restraining effect by the control method of the automatic transmission vehicle shown in fig. 9.

Fig. 13 (a) to 13 (e) are waveform diagrams illustrating control states in downhill prediction and downhill control based on the control method of the automatic transmission vehicle shown in fig. 9.

[ description of symbols ]

1: vehicle with a steering wheel

100: vehicle control device

110: automatic driving control part

120: running control unit

EG: engine (internal combustion engine)

TM: step automatic transmission

CVT: continuously variable transmission

Detailed Description

1. Brief description of the embodiments

In a vehicle equipped with an automatic transmission, when there is time before a drive force is required during automatic driving, the drive force and the vehicle speed are maintained constant for a predetermined period before the increase timing of the drive force is required, the engine speed is increased, the engine torque is decreased according to the increase in the engine speed, and the shift stage is downshifted. This can greatly alleviate the feeling of incongruity caused by a sudden increase in the engine speed and a shift shock when the driving force is actually increased.

An example of an automatic drive control and automatic transmission vehicle on which the present invention is based will be described below with reference to fig. 1 and 2, and embodiments of the present invention will be described in detail below.

2. Automatic driving control

As illustrated in fig. 1, the vehicle 1 is a two-wheel, three-wheel, four-wheel, or the like automobile, and in the present embodiment, as described later, is a vehicle including an automatic transmission. However, the application of the automatic driving control may be an automobile using a diesel engine, a gasoline engine, or the like as a drive source, or an electric automobile that drives a motor using electric power obtained from a secondary battery, a hydrogen fuel cell, a metal fuel cell, an alcohol fuel cell, or the like.

< device structure of vehicle >

The vehicle 1 is equipped with the following devices and equipment groups in addition to the vehicle control device 100 that performs vehicle control including automatic driving control.

Means for acquiring various information from outside the vehicle 1 (including the external situation acquisition unit 12, the route information acquisition unit 13, the driving state acquisition unit 14, and the like, and other buttons, dial switches, Graphical User Interface (GUI) switches, and the like),

Operating devices (an accelerator pedal 70, a brake pedal 72, a steering wheel 74, a changeover switch 80, and the like),

an operation detection sensor (an accelerator opening sensor 71 for detecting the accelerator opening of the accelerator pedal 70, a brake depression amount sensor (brake switch) 73 for detecting the depression amount of the brake pedal 72, a steering angle sensor (or steering torque sensor) 75 for detecting the steering angle of the steering wheel 74), and a control unit (a control unit) for controlling the operation of the steering wheel,

A reporting device (output unit) 82,

Devices (driving force output device (driving device) 90, steering device 92, and brake device 94) for driving or steering the vehicle 1, and

a communication line and a Network (Controller Area Network (CAN), a wireless communication Network, and the like) for connecting these devices or apparatuses.

The external situation acquisition unit 12 is configured to acquire external situations of the vehicle 1, for example, environmental information around the vehicle such as a lane of a traveling road or an object around the vehicle, and includes, for example: various cameras (monocular camera, stereo camera, infrared camera, etc.) or various radars (millimeter wave radar, microwave radar, laser radar, etc.), and the like. In addition, a fusion sensor (fusion sensor) that integrates information obtained by a camera and information obtained by a radar may also be used.

The route information acquiring unit 13 includes a navigation device. The Navigation device includes a Global Navigation Satellite System (GNSS) receiver, map information (Navigation map), a touch panel display device functioning as a user interface, a speaker, a microphone, and the like. The navigation device determines the position of the vehicle 1 by the GNSS receiver, and derives a route from the position to a destination specified by the user. The route derived by the navigation device is stored in the storage unit 140 as route information 144. The position of the vehicle 1 may be determined or supplemented by an Inertial Navigation System (INS) using the output of the traveling state acquiring unit 14. In addition, when the vehicle control device 100 is executing manual driving control, the navigation device guides a route to a destination by sound or navigation display. Further, the structure for determining the position of the vehicle 1 may also be provided independently of the navigation device. The navigation device may be realized by a function of a terminal device such as a smartphone or a tablet terminal held by a user. In this case, information is transmitted and received between the terminal device and the vehicle control device 100 by wireless or wired communication.

The traveling state acquisition unit 14 is configured to acquire the current traveling state of the vehicle 1. The running state acquisition unit 14 includes: a travel position acquisition unit 26, a vehicle speed acquisition unit 28, a yaw rate acquisition unit 30, a steering angle acquisition unit 32, and a travel track acquisition unit 34.

The traveling position acquisition unit 26 is configured to acquire a traveling position of the vehicle 1 and a posture (traveling direction) of the vehicle 1, which are one of traveling states. The travel position acquisition unit 26 includes various Positioning devices, for example, a device (a Global Positioning System (GPS) receiver, a GNSS receiver, a beacon (beacon) receiver, or the like) that receives electromagnetic waves transmitted from satellites or on-road devices to acquire position information (latitude, longitude, altitude, coordinates, or the like), a gyro sensor, an acceleration sensor, and the like. The traveling position of the vehicle 1 is measured with reference to a specific portion of the vehicle 1.

The vehicle speed acquisition unit 28 is configured to acquire a speed of the vehicle 1 (hereinafter, referred to as a vehicle speed) which is one of the traveling states. The vehicle speed acquisition unit 28 includes, for example, a speed sensor or the like provided on one or more wheels.

The yaw rate acquisition unit 30 is configured to acquire the yaw rate of the vehicle 1, which is one of the traveling states. The yaw rate acquisition unit 30 includes, for example, a yaw rate sensor.

The steering angle obtaining unit 32 is configured to obtain a steering angle that is one of the traveling states. The steering angle acquiring unit 32 includes, for example, a steering angle sensor provided on a steering shaft (steering shaft). Here, the steering angular velocity and the steering angular acceleration are also acquired from the acquired steering angle.

The travel track acquisition unit 34 is configured to acquire information (actual travel track) of an actual travel track of the vehicle 1, which is one of the travel states. The actual travel track includes a track (track) on which the vehicle 1 has actually traveled, and may include a predetermined track to be traveled, for example, an extension line on the front side in the travel direction of the track (track) on which the vehicle has traveled. The travel track acquisition unit 34 includes a memory. The memory stores position information of a series of dot sequences included in the actual travel track. In addition, the extension line can be predicted by a computer or the like.

The accelerator opening sensor 71, the brake depression amount sensor 73, and the steering angle sensor 75, which are operation detection sensors, output the detected accelerator opening, brake depression amount, and steering angle to the vehicle control device 100.

The changeover switch 80 is a switch operated by an occupant of the vehicle 1. The changeover switch 80 receives an operation by the occupant, and switches the driving mode (for example, automatic driving control and manual driving control) according to the received operation content. The changeover switch 80 generates a driving mode designation signal that designates the driving mode of the vehicle 1 in accordance with the operation content of the occupant, and outputs it to the vehicle control device 100.

In addition, the vehicle 1 includes a shift device 60 that is operated by a driver via a shift lever (shift lever). As shown in fig. 1, the shift lever (not shown) of the shift device 60 is positioned, for example, at P (parking), R (reverse travel), N (neutral), D (forward travel in the automatic shift mode (normal mode)), S (forward travel in the sport mode), and the like. A shift position sensor 205 is provided in the vicinity of the shifting device 60. The shift position sensor 205 detects the position of a shift lever operated by the driver. The vehicle control device 100 inputs information of the gear position detected by the gearshift position sensor 205.

Further, the vehicle 1 of the present embodiment includes a paddle switch 65 provided near the steering wheel 74. The paddle switch 65 includes: a-switch (negative button) 66 for instructing a downshift in a manual shift mode (manual mode) at the time of manual driving (manual driving mode), and a + switch (positive button) 67 for instructing an upshift in the manual shift mode. In the manual shift mode of the automatic transmission TM in the manual drive mode, operation signals of the negative button 66 and the positive button 67 are output to the electronic control unit (vehicle control device) 100, and an upshift or a downshift of the set shift stage is performed by the automatic transmission TM in accordance with the running state of the vehicle 1 and the like. In the present embodiment, during manual driving, for example, when the automatic shift mode is set at the position of the shift lever in the D range or the S range, when the driver operates either paddle switch 66 or paddle switch 67, the automatic shift mode is switched to the manual shift mode (manual mode). In addition, at the time of automatic driving, a function (a function different from that at the time of manual driving) to be described in detail below is given to the operation of the paddle switch 65.

The reporting device 82 is a device or a group of machines that can output various information. The reporting device 82 outputs information for urging a transition from the automatic driving control to the manual driving control to an occupant of the vehicle 1, for example. As the reporting device 82, for example, at least one of a speaker, a vibrator, a display device, a light-emitting device, and the like can be used.

The occupant recognition unit 15 includes, for example, an in-vehicle camera that can photograph the interior of the vehicle 1. The in-vehicle camera may be a digital camera using a solid-state imaging Device such as a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS), or a near-infrared camera combined with a near-infrared light source. The vehicle control device 100 can acquire an image captured by the occupant recognition unit 15 (in-vehicle camera), and recognize the current driver of the vehicle 1 from the image of the face of the driver of the vehicle 1 included in the image.

As illustrated in fig. 2, the driving force output device (driving device) 90 for running includes an internal combustion engine (engine) EG as a driving source, an Automatic Transmission TM connected to the engine EG via a torque converter TC with a lock-up clutch (lock-up clutch), a Fuel Injection (FI) -Electronic Control Unit (ECU) 4 for controlling the engine EG, and an Automatic Transmission (AT) -ECU 5 for controlling the Automatic Transmission TM. In the case where the driving force output device 90 for running is configured to include the engine EG and the automatic transmission TM, the FI-ECU 4 and the AT-ECU 5 control the driving force (torque) for running the vehicle 1 by controlling the throttle opening of the engine EG and the shift stage of the automatic transmission TM in accordance with information input from a running control unit 120 described later in fig. 1.

The steering device 92 includes, for example, an electric motor. The electric motor changes the direction of the steering wheel by applying a force to a rack and pinion (rack and pinion) mechanism, for example. The steering device 92 drives the electric motor to change the direction of the steered wheels in accordance with information input from the travel control unit 120.

The brake device 94 is, for example, an electric servo brake device including: the brake caliper includes a brake caliper, a cylinder for transmitting hydraulic pressure to the brake caliper, an electric motor for generating hydraulic pressure in the cylinder, and a brake control unit for controlling the cylinder and the electric motor to control braking of the brake caliper. The electric servo brake device is a braking force output device, and the brake control unit controls the electric motor in accordance with information input from the travel control unit 120, and controls so that a braking torque that outputs a braking force corresponding to a braking operation is output to each wheel. The electric servo brake device may include a mechanism that transmits hydraulic pressure generated by operation of the brake pedal 72 to the cylinder via the master cylinder as a backup element. The brake device 94 is not limited to the electric servo brake device described above, and may be an electronically controlled hydraulic brake device. The electronic control type hydraulic brake device controls the actuator according to information input from the travel control unit 120, and transmits the hydraulic pressure of the master cylinder to the cylinder.

< control device >

Next, the vehicle control device 100 will be explained. The vehicle control device 100 includes: an automatic driving control unit 110, a travel control unit 120, and a storage unit 140. Each Unit of the automatic driving control Unit 110 and a part or all of the travel control Unit 120 are realized by executing a program by a processor such as a Central Processing Unit (CPU). Some or all of them may be realized by hardware such as a Large Scale Integration (LSI) or an Application Specific Integrated Circuit (ASIC). The storage unit 140 is implemented by a Read Only Memory (ROM), a Random Access Memory (RAM), a Hard Disk Drive (HDD), a flash Memory, or the like. The program executed by the processor may be stored in the storage unit 140 in advance, or may be downloaded from an external device via an in-vehicle internet device or the like. The program may be installed in the storage unit 140 by installing a portable storage medium storing the program in a drive device not shown. Further, the vehicle control device 100 may be distributed by a plurality of computer devices. Thus, the hardware functional unit described above can be realized in cooperation with software including a program and the like in the vehicle-mounted computer of the vehicle 1 to realize various processes in the present embodiment.

The storage unit 140 stores map information 142, route information 144, and action plan information 146.

The map information 142 is, for example, map information having higher accuracy than the navigation map of the route information acquisition unit 13, and includes information on the center of a lane, information on the boundary of a lane, and the like. More specifically, the map information 142 includes road information, traffic control information, address information (address/postal code), facility information, telephone number information, and the like. The road information includes information indicating the type of road such as a highway, a toll road, a national road, and a prefecture road, and information such as the number of lanes on the road, the width of each lane, the gradient of the road, the position of the road (including three-dimensional coordinates of longitude, latitude, and height), the curvature of a turn of the lane, the positions of merging and diverging points of the lane, and a sign provided on the road. The traffic control information includes information such as that a lane is blocked due to a construction, a traffic accident, or a traffic jam.

The route information 144 is an element stored in the storage unit 140, and is a route from which a route to a destination designated by the user is derived by specifying the position of the vehicle 1 by, for example, a GNSS receiver of the navigation device constituting the route information acquisition unit 13.

The action plan information 146 is an element stored in the storage unit 140, and is information indicating an action plan generated by the action plan generating unit 116 of the automated driving control unit 110 based on the map information acquired by the route information acquiring unit 13.

The automatic driving control portion 110 includes: a vehicle position recognition unit 112, an external environment recognition unit 114, an action plan generation unit 116, and a target traveling state setting unit 118.

The automatic driving control unit 110 switches the driving mode and controls the driving mode in accordance with the input of a signal from the changeover switch 80. The driving mode includes an automatic driving mode (automatic driving control) in which acceleration/deceleration and steering of the vehicle 1 are automatically controlled, and a manual driving mode (manual driving control) in which acceleration/deceleration of the vehicle 1 is controlled by a manual operation of an operation device such as the accelerator pedal 70 or the brake pedal 72, and steering is controlled by a manual operation of an operation device such as the steering wheel 74. As another driving mode, for example, a semi-automatic driving mode (semi-automatic driving control) may be included in which one of acceleration and deceleration and steering of the vehicle 1 is automatically controlled and the other is controlled by a human operation on an operation device.

The vehicle position recognition unit 112 recognizes the lane in which the vehicle 1 is traveling (traveling lane) and the relative position of the vehicle 1 with respect to the traveling lane, based on the map information 142 stored in the storage unit 140 and the information input from the external situation acquisition unit 12, the route information acquisition unit 13, or the traveling state acquisition unit 14. The vehicle position recognition unit 112 recognizes, for example, a deviation of a reference point (for example, the center of gravity) of the vehicle 1 from the center of the traveling lane and an angle formed by the traveling direction of the vehicle 1 with respect to a line connecting the centers of the traveling lanes as the relative position of the vehicle 1 with respect to the traveling lane. Alternatively, the vehicle position recognition unit 112 may recognize the position of the reference point of the vehicle 1 with respect to either side end of the own lane, as the relative position of the vehicle 1 with respect to the traveling lane.

The environment recognition unit 114 recognizes the state of the peripheral vehicle such as the position, speed, and acceleration based on the information input from the external situation acquisition unit 12. The peripheral vehicle in the present embodiment is another vehicle that travels in the periphery of the vehicle 1, and is a vehicle that travels in the same direction as the vehicle 1. In particular, the peripheral vehicle in the present embodiment refers to a front vehicle that the vehicle 1 is about to pass over and a rear vehicle that the vehicle 1 is about to pass over. The position of the nearby vehicle may be represented by a representative point such as the center of gravity or an angle of the vehicle 1, or may be represented by a region expressed by the outline of the vehicle 1. The "state" of the nearby vehicle may include whether or not the acceleration change or the lane change of the nearby vehicle is being performed (or whether or not the lane change is being performed) based on the information of the various devices. In addition to the surrounding vehicles, the environment recognition unit 114 may recognize the position of other objects such as guard rails, utility poles, parking vehicles, and pedestrians.

The action plan generating unit 116 sets a start point of the automated driving, a scheduled end point of the automated driving, and/or a destination of the automated driving. The starting point of the automated driving may be the current position of the vehicle 1, or may be a point at which an operation for instructing the automated driving is performed by a passenger of the vehicle 1.

The action plan generated by the action plan generating unit 116 includes, for example, a plurality of events that are executed in sequence for predetermined points on the road on which the vehicle will travel next. Among the events, for example, are: a deceleration event for decelerating the vehicle 1 or an acceleration event for accelerating the vehicle 1, a lane-keeping event for driving the vehicle 1 without departing from the driving lane, a lane-changing event for changing the driving lane, a passing event for passing the vehicle 1 over a preceding vehicle, a diversion event for changing the lane to a desired lane at a diversion point or driving the vehicle 1 without departing from the current driving lane, a merging event for accelerating or decelerating the vehicle 1 on a merging lane for merging with the main road and changing the driving lane, and the like.

The target traveling state setting unit 118 is configured as follows: the target traveling state, which is the target traveling state of the vehicle 1, is set based on the action plan determined by the action plan generating unit 116 and the various information acquired by the external situation acquiring unit 12, the route information acquiring unit 13, and the traveling state acquiring unit 14. The target traveling state setting unit 118 includes a target value setting unit 52, a target trajectory setting unit 54, a deviation acquiring unit 42, and a correcting unit 44.

The target value setting unit 52 is configured as follows: information of a traveling position (latitude, longitude, altitude, coordinates, etc.) targeted by the vehicle 1 (also simply referred to as a target position), target value information of a vehicle speed (also simply referred to as a target vehicle speed), and target value information of a yaw rate (also simply referred to as a target yaw rate) are set.

The target trajectory setting unit 54 is configured as follows: information of a target track (also simply referred to as a target track) of the vehicle 1 is set based on the external situation acquired by the external situation acquisition unit 12 and the travel route information acquired by the route information acquisition unit 13. The target track contains information of the target position per unit time. The posture information (traveling direction) of the vehicle 1 is associated with each target position. In addition, target value information such as vehicle speed, acceleration, yaw rate, lateral acceleration, steering angle, steering angular velocity, and steering angular acceleration may be associated with each target position. The target position, the target vehicle speed, the target yaw rate, and the target track described above are information indicating the target running state.

The deviation acquisition unit 42 is configured as follows: the deviation of the target running state from the actual running state is acquired based on the target running state set by the target value setting unit 52 and the target trajectory setting unit 54 of the target running state setting unit 118 and the actual running state acquired by the running state acquisition unit 14.

The correction unit 44 is configured to correct the target traveling state in accordance with the deviation acquired by the deviation acquisition unit 42. Specifically, the correction unit 44 sets a new target traveling state such that the target traveling state set by the target traveling state setting unit 118 is closer to the actual traveling state acquired by the traveling state acquisition unit 14 as the deviation becomes larger.

The travel control unit 120 includes an acceleration/deceleration command unit 56 and a steering command unit 58, and is configured to control the travel of the vehicle 1. Specifically, the travel control unit 120 outputs the command value for travel control to the above-described driving force output device for traveling 90, steering device 92, and braking device 94 so that the actual traveling state of the vehicle 1 matches or approaches the target traveling state set by the target traveling state setting unit 118 or the new target traveling state set by the correction unit 44.

The acceleration/deceleration command unit 56 is configured to perform acceleration/deceleration control in the travel control of the vehicle 1. Specifically, the acceleration/deceleration command unit 56 calculates an acceleration/deceleration command value for matching the running state of the vehicle 1 with the target running state, based on the target running state (target acceleration/deceleration) set by the target running state setting unit 118 or the correction unit 44 and the actual running state (actual acceleration/deceleration).

The steering command unit 58 is configured to perform steering control in the running control of the vehicle 1. Specifically, the steering command unit 58 calculates a steering angular velocity command value for matching the actual running state of the vehicle 1 with the target running state, based on the target running state and the actual running state set by the target running state setting unit 118 or the correction unit 44.

3. First embodiment (drive system with automatic transmission)

Fig. 2 schematically shows the configuration of a driving force output device (driving device) 90 for running of the vehicle 1. The rotation of the engine EG is output to a crankshaft (output shaft of the engine EG) 221, and is transmitted to an input shaft 227 of the automatic transmission TM via a torque converter TC. The automatic transmission TM is a stepped automatic transmission that is capable of setting a plurality of shift stages for forward travel and a first shift stage for reverse travel, and that shifts the rotation transmitted from the engine EG to the input shaft 227 and outputs the rotation from the output shaft 228 to the drive wheel side.

Further, the driving force output device for running 90 includes: an FI-ECU (fuel injection control device) 4 that electronically controls the engine EG; an AT-ECU (automatic transmission control device) 5 that electronically controls an automatic transmission TM including a torque converter TC; and a hydraulic control device 6 that hydraulically controls rotation driving and lock-up control of the torque converter TC and engagement (engagement)/release of a plurality of friction engagement mechanisms included in the automatic transmission TM, in accordance with control of the AT-ECU 5.

The vehicle 1 includes: a crank speed sensor 201, an input shaft speed sensor 202, and an output shaft speed sensor 203. The crank rotation speed sensor 201 detects a rotation speed Ne of the crankshaft 221 (engine EG) and outputs the rotation speed Ne to the AT-ECU 5 and the FI-ECU (fuel injection control device) 4. The input shaft rotation speed sensor 202 detects the rotation speed Ni of the input shaft 227 (the input shaft rotation speed of the automatic transmission TM) and outputs the rotation speed Ni to the AT-ECU 5. The output shaft rotation speed sensor 203 detects the rotation speed No of the output shaft 228 (the output shaft rotation speed of the automatic transmission TM) and outputs the rotation speed No to the AT-ECU 5. The AT-ECU 5 calculates vehicle speed data from the rotation speed data Ne, the rotation speed data Ni, and the rotation speed data No detected by the sensors 201 to 203. In addition, the vehicle 1 includes a throttle opening sensor 206. The throttle opening sensor 206 detects a throttle opening TH of the engine EG and outputs data of the throttle opening TH to the FI-ECU 4.

The AT-ECU 5 that controls the automatic transmission TM has a shift map (shift characteristics) 55, and the shift map (shift characteristics) 55 determines a range of a gear that can be set by the automatic transmission TM, based on the vehicle speed detected by the vehicle speed sensor of the vehicle speed acquisition unit 28 and the accelerator opening detected by the accelerator opening sensor 71. The shift map 55 includes an upshift line and a downshift line set for each shift stage, and a plurality of kinds of shift maps having different characteristics are prepared in advance. In the shift control of the automatic transmission TM, the AT-ECU 5 performs control for switching the shift stage of the automatic transmission TM in accordance with a shift map selected from the plurality of shift maps.

< automatic Driving control >

In the vehicle 1, when the automated driving mode is selected by the operation of the changeover switch 80 by the driver, the automated driving control portion 110 performs automated driving control of the vehicle 1. In the automatic driving control, the automatic driving control unit 110 grasps the current driving state (actual driving track, driving position, etc.) of the vehicle 1 based on information acquired from the external situation acquisition unit 12, the route information acquisition unit 13, the driving state acquisition unit 14, etc., or information recognized by the own vehicle position recognition unit 112 and the external world recognition unit 114. The target traveling state setting unit 118 sets a target traveling state (target trajectory or target position) which is a target traveling state of the vehicle 1, based on the action plan generated by the action plan generating unit 116. The deviation acquisition unit 42 acquires a deviation of the actual running state from the target running state. When the deviation is acquired by the deviation acquisition unit 42, the travel control unit 120 performs travel control so that the travel state of the vehicle 1 matches or approaches the target travel state.

The correction unit 44 corrects the target track or the target position based on the travel position acquired by the travel position acquisition unit 26. The travel control unit 120 performs acceleration/deceleration control of the vehicle 1 using the driving force output device for travel 90 and the brake device 94 so that the vehicle 1 follows a new target trajectory or target position, based on the vehicle speed and the like acquired by the vehicle speed acquisition unit 28.

The correction unit 44 corrects the target track based on the travel position acquired by the travel position acquisition unit 26. The travel control unit 120 performs steering control by the steering device 92 so that the vehicle 1 follows a new target trajectory, based on the steering angular velocity acquired by the steering angle acquisition unit 32.

Here, the vehicle 1 has a braking function by a brake device (mechanical braking mechanism) 94 and a braking function by an engine brake (internal combustion engine braking mechanism) that generates a braking force using the engine EG and the automatic transmission TM.

4. Control method

Hereinafter, a control method according to a first embodiment of the present invention will be described in detail. The control method according to the present embodiment may be installed in the system described above. The acceleration/driving force control during passing is described here, but the present invention is applicable not only to the case of passing, but also to a situation in which a sudden increase in driving force is expected.

4.1) Overtaking control

In fig. 3, a vehicle a is the vehicle 1 to which the control method according to the present embodiment is mounted, a vehicle B is a preceding vehicle that should be overtaken, and a vehicle C is a rear vehicle that is approaching the vehicle a to overtake the vehicle a or a preceding vehicle that is traveling on a passing lane. Such a nearby vehicle is identified by the outside world identification portion 114 as described above.

In the normal travel 301, it is assumed that the external world identification unit 114 has identified the approach of the rear vehicle C when a determination is made that the vehicle a passes the front vehicle B based on the present embodiment. When it is determined that the rear vehicle C is approaching to overtake the own vehicle, the vehicle control apparatus 100 suspends the acceleration for overtaking (the acceleration standby 302 and the acceleration standby 303) until the rear vehicle C overtakes. Then, after the vehicle C overtakes, when it is determined that overtaking is possible, the vehicle control device 100 changes the lane to the overtaking lane, increases the required driving force and accelerates to perform overtaking (acceleration overtaking 304). If the preceding vehicle C traveling on the passing lane is recognized, the passing may be performed when the preceding vehicle C returns to the passing lane.

According to the present embodiment, during the time when the acceleration standby state 302 and the acceleration standby state 303 in fig. 3 are in progress, the downshift of the automatic transmission TM is performed more slowly than usual. Since the action plan is followed during the automatic driving as described above, the shifting of the automatic transmission TM during the acceleration standby may be performed more slowly than the usual shifting. That is, in order to perform the downshift, the vehicle control device 100 executes control to gradually increase the engine speed and reduce the engine torque while maintaining the driving force and the vehicle speed constant. By performing the downshift in this manner, the shift shock can be eliminated or alleviated, and the feeling of discomfort of the occupant due to sudden changes in engine sound and vibration can be suppressed.

The control method according to the present embodiment is implemented by the vehicle control device 100 described above. The control function thereof may be realized by executing a program stored in a memory on a processor of the vehicle control device 100. An example of the control method according to the present embodiment will be described below with reference to fig. 4.

In fig. 4, when it is determined that the preceding vehicle B has overtaken (YES in act 401), the automatic driving control portion 110 first calculates a target acceleration/driving force (required driving force) (act 402), and then recognizes the surrounding situation based on the information from the external situation acquisition portion 12, and determines whether or not there is a following vehicle C approaching the overtaking lane (act 403). If there is a rear vehicle C (yes in act 403), the automatic driving control unit 110 waits for execution of overtaking acceleration (act 404).

When the shift-up standby state is established, vehicle control device 100 increases engine speed NE to a target value while decreasing engine torque so as to maintain constant driving force of engine EG and vehicle speed V during shift time Ts2, and executes a downshift when engine speed NE reaches a speed corresponding to the gear ratio after the shift (act 405). The shift time Ts2 is set to be longer than the normal shift time Ts1 by slowing engagement of the clutch in the automatic transmission TM and the lock-up clutch of the torque converter TC. The vehicle speed V of the vehicle a may be reduced during the acceleration standby period so as not to excessively approach the front vehicle B or so as to allow the rear vehicle C to pass through as quickly as possible.

When it is determined that the vehicle can overtake without the rear vehicle (NO in act 403), the automatic drive control unit 110 executes the acceleration/drive force control with the target acceleration/drive force calculated in act 402 in accordance with the operation schedule (act 407). Acceleration/drive force control is performed (act 407) until the end of the cut-in (act 408).

If it is determined that overtaking is not to be performed (no in act 401), the vehicle control apparatus 100 determines whether or not downshift for automatic driving is completed (act 409). When the downshift for automatic driving is completed (yes in act 409), vehicle control device 100 determines that acceleration is suspended, decreases engine speed NE and increases engine torque so that the driving force of engine EG and vehicle speed V are maintained constant, and executes an upshift when engine speed NE reaches a speed corresponding to the gear ratio after the shift (act 410). If the automatic drive downshift is not executed (no in act 409), the steps 401 and 409 are repeated until the next passing determination (no in act 401 and no in act 409).

Although the control during overtaking has been described as an example, the present invention is applicable to a situation in which a sudden increase in driving force is predicted and time has elapsed until then. Hereinafter, assuming a general case, a change in the state of the vehicle 1 when acceleration is performed after the acceleration standby will be described with reference to fig. 5 (a) to 5 (f).

4.2) accelerated standby and accelerated execution (first gear downshift)

As illustrated in fig. 5 (a) to 5 (f), it is assumed that the accelerated standby is determined at time t 1. The vehicle control device 100 calculates a required driving force in advance, and gradually increases (c) the engine speed NE and gradually decreases (d) the engine torque during the period when the shift time Ts2 elapses from the start of the acceleration standby. For example, the engine torque may be reduced by reducing the throttle opening. Since the engine torque decreases even when the engine rotation speed NE increases, the vehicle control device 100 can maintain the vehicle speed V and the driving force constant ((b) of fig. 5 and (f) of fig. 5).

When the downshift is performed at the time point t2, the engine speed NE and the speed change ratio of the automatic transmission TM are in a state in which the actual acceleration can be performed. Therefore, when the actual acceleration is performed at time t3, the vehicle control device 100 increases the engine torque to the target value (d) and increases the driving force required for acceleration to the required value (b). The engine torque can be raised by raising the throttle opening. At this time, the speed ratio of the automatic transmission TM and the engine speed NE do not change.

Conventionally, between time t3 and time t4, the engine speed NE is increased during the normal shift time Ts1 (broken line in fig. 5 c), and the downshift (e) is executed. Therefore, the engine sound and vibration suddenly change during the shift time Ts1, which causes a large discomfort to the occupant. In contrast, according to the present embodiment, the downshift is performed at the shift time Ts2 that is longer than the normal shift time Ts 1. Since the shift time Ts2 can be set during the acceleration standby, the engine speed NE can be increased more gradually, and the discomfort of the conventional art can be greatly reduced.

4.3) accelerated standby and accelerated execution (Multi-gear downshift)

In the above-described control illustrated in fig. 5 (a) to 5 (f), the downshift of the first gear is performed during the upshift standby, but there may be cases where a multiple gear shift is required. Hereinafter, a case of shifting down two stages from the N stage to the (N-2) stage will be described as an example.

As illustrated in fig. 6 (a) to 6 (f), it is assumed that the accelerated standby is determined at time t 1. The vehicle control apparatus 100 calculates the required driving force in advance, downshifts from the N-speed to the N-1 speed at a time point t2 when a shift time Ts2 elapses from the start of the on-standby, and then downshifts from the N-1 speed to the N-2 speed at a time point t3 when a shift time Ts2 elapses. During this period, the engine speed NE is gradually increased (c) and the engine torque is gradually decreased (d). In this way, the vehicle control device 100 can perform control so that the vehicle speed V and the driving force are maintained constant ((b) of fig. 5 and (f) of fig. 5).

At time t3, the downshift to the N-2 speed occurs, so that the engine speed NE and the speed ratio of the automatic transmission TM are in a state where the actual acceleration can be performed. Therefore, when the actual acceleration is started at time t4, the vehicle control device 100 increases the engine torque to the target value (d) and increases the driving force required for acceleration to the required value (b). At this time, the speed ratio of the automatic transmission TM does not change from the engine speed NE.

In the above example, since the two-speed downshift is performed within 2 times the shift time Ts2, the engine speed NE changes more slowly, and the sense of incongruity as in the conventional art is greatly reduced. Further, although the two-speed downshift is described in the above example, a downshift of three or more gears may be performed, and if the downshift is completed to two speeds during the upshift standby, the number of final downshift stages may be reduced in accordance with the number of stages, and the same effect may be obtained.

Further, the output of the engine EG may be lowered by environmental conditions, and conventionally, as shown by a broken line in fig. 6 (d), when the engine torque reaches the upper limit at time t5, the engine speed NE is abruptly increased in order to perform a downshift at the shift time Ts 1. This gives a sense of incongruity to the occupant. In contrast, according to the present embodiment, since the downshift is performed during the acceleration standby, such a sharp increase in the engine rotation speed NE can be avoided.

In addition, conventionally, during automatic driving, when driving at high speed with a high frequency of use, there is a case where a shift busy state occurs in which downshifts or upshifts are frequently repeated.

4.4) downhill control

The control method according to the present embodiment is applicable as long as the condition of downshift is predicted. For example, when it is recognized from the map information that there is a downward slope ahead, the sense of incongruity as in the conventional art can be greatly reduced by performing the smooth gear shift described above before the downward slope is reached. The following description will be made with reference to fig. 7 and 8 (a) to 8 (e).

In fig. 7, when it is predicted that there is a downward slope ahead ("yes" in act 501), the automatic drive control unit 110 calculates a target acceleration/driving force (required driving force) (act 502), and determines whether or not a downshift should be started in advance from a time before the downward slope (act 503). If the start is to be made (yes in act 503), the vehicle control device 100 increases the engine rotation speed NE to a target value while decreasing the engine torque so as to maintain the vehicle speed V constant during the shift time Ts2 (act 504), and executes a downshift when the engine rotation speed NE reaches a rotation speed corresponding to the gear ratio after the shift (act 505). As described above, the shift time Ts2 is set to be longer than the normal shift time Ts1 by slowing the engagement of the clutch in the automatic transmission TM and the lock-up clutch of the torque converter TC. Then, downhill control is performed in downhill (action 506).

As illustrated in fig. 8 (a) to 8 (e), it is assumed that the downhill prediction is determined at time t 1. The vehicle control device 100 calculates the required driving force in advance, and gradually increases (b) the engine speed NE and gradually decreases (c) the engine torque during the elapse of the shift time Ts2 from the time point t 1. For example, the engine torque may be reduced by reducing the throttle opening. Since the engine torque decreases even if the engine speed NE increases, the vehicle control device 100 can control the vehicle speed V to be constant.

When the downshift is performed at the time point t2, the engine speed NE and the speed change ratio of the automatic transmission TM are in a state in which the actual downhill control can be performed. Therefore, when the actual downhill slope is reached at time t3, the vehicle control device 100 executes Fuel Cut (FC) control for stopping the supply of fuel to the engine EG based on the braking force determined based on the action plan and causing the engine to brake. At this time, the speed ratio of the automatic transmission TM and the engine speed NE do not change.

Conventionally, between time t3 and time t4, the engine speed NE is increased during the normal shift time Ts1 (broken line in fig. 8 b), and the downshift (d) is executed. Therefore, the engine sound and vibration suddenly change during the shift time Ts1, causing a large discomfort to the occupant. In contrast, according to the present embodiment, since the downshift is performed for the shift time Ts2 that is longer than the normal shift time Ts1, the engine speed NE changes more slowly, and the sense of incongruity as in the past is greatly reduced.

5. Second embodiment

The present invention is applicable not only to a vehicle equipped with a multi-stage Transmission but also to a vehicle equipped with a Continuously Variable Transmission (CVT) known as a Continuously Variable Transmission (CVT). Next, a continuously variable transmission vehicle according to a second embodiment of the present invention will be described.

A CVT is a winding type automatic transmission in which a winding member such as a metal belt or a chain is wound between pulleys disposed to face each other. Since the gear ratio can be adjusted steplessly, there is an advantage that the power band of the engine can be effectively utilized as compared with a stepped transmission, but deterioration of drivability (drivability) called a rubber belt feel is also pointed out.

5.1) drive System with CVT

Fig. 9 schematically shows the configuration of a driving force output device (driving device) 90 for running in the vehicle 1 according to the present embodiment. Vehicle 1 includes a drive wheel 612, and engine 610 as an internal combustion engine is mounted on vehicle 1.

A throttle valve (not shown) disposed in an intake system of the engine 610 is connected to a Drive By Wire (DBW) mechanism 618 including an actuator such as an electric motor, and is opened and closed By the DBW mechanism 618.

The intake air adjusted by the throttle valve flows through the intake manifold, is mixed with the fuel injected from the injector 620 in the vicinity of the intake port of each cylinder to form an air-fuel mixture, and flows into the combustion chamber of the cylinder when the intake valve is opened. In the combustion chamber, the air-fuel mixture is ignited by a spark plug and burned, and after driving the piston to rotate the crankshaft 622, the air-fuel mixture becomes exhaust gas and is discharged to the outside of the engine 610.

The rotation of the crankshaft 622 is input to a CVT 626 via a torque converter 624. That is, the rotation of the output shaft of the engine 610 determined by the throttle opening degree adjusted by the DBW mechanism 618 according to the operation of the accelerator pedal 616 by the driver is input to the CVT 626 via the torque converter 624.

The crankshaft 622 of the engine 610 is connected to a pump/impeller 624a of a torque converter 624. On the other hand, a turbine runner 624b, which is disposed opposite to the turbine runner and receives fluid (hydraulic oil), is connected to the main shaft (input shaft) MS. The torque converter 624 includes a lockup clutch 624 c.

The CVT 626 includes: an input pulley (Drive pulley) 626a disposed on the spindle MS; an output pulley (driven (DN) pulley) 626b disposed in parallel with the main shaft MS and on an intermediate shaft (output shaft) CS coupled to the drive wheels 612; and a loop-shaped transmission member, for example, a metal band 626c, wound around and suspended therebetween.

CVT 626 is connected to the engine 610 via a forward-reverse switching mechanism 628. The forward/reverse switching mechanism 628 includes: a forward clutch 628a that enables the vehicle 1 to travel in a forward direction; a reverse brake clutch 628b that enables the vehicle 1 to travel in a reverse direction; and a planetary gear mechanism 628c disposed therebetween.

The rotation of the intermediate shaft CS is transmitted from a countershaft (intermediate shaft) SS to the drive wheels 612 via gears. That is, the rotation of the intermediate shaft CS is transmitted to the counter shaft SS via the gears 630a and 630b, and the rotation is transmitted from the differential mechanism (differential mechanism)632 to the left and right drive wheels (only the right side is shown) 612 via the drive shaft (drive draft) 634 via the gear 630 c. In the above description, the gear 630a, the gear 630b, and the gear 630c are collectively referred to as "output gear 630".

Disc brakes 636 are disposed near four wheels including the drive wheels (front wheels) 612 and the driven wheels (rear wheels, not shown), and a brake pedal 640 is disposed on a vehicle driving floor.

In the forward/reverse switching mechanism 628, the forward clutch 628a and the reverse brake clutch 628b are switched by the driver operating a range selector 644 provided in the driver's seat of the vehicle to select any one of ranges such as P, R, N, D. The range selection based on the operation of the driver's range selector 644 is transmitted to the manual valve of the hydraulic pressure supply mechanism 646.

Although not shown, the hydraulic pressure supply mechanism 646 includes: a hydraulic pump that draws up hydraulic oil from a reservoir (reservoir) and discharges the hydraulic oil to an oil passage, various control valves and electromagnetic valves disposed in the oil passage, which are driven by the engine 610, supplies hydraulic pressure obtained by adjusting the pressure of the discharged hydraulic oil to the lock-up clutch 624c of the torque converter 624, and engages/disengages the lock-up clutch 624 c.

The hydraulic pressure supply mechanism 646 supplies hydraulic pressure to piston chambers of the pulleys 626a and 626b of the CVT 626. As a result, the pulley width between the pulleys 626a and 626b changes, and the winding radius of the belt 626c changes, so that the speed ratio (ratio) at which the rotation of the engine 610 is transmitted to the drive wheels 612 continuously changes.

Further, the hydraulic pressure supply mechanism 646 supplies hydraulic pressure to the piston chambers of the forward clutch 628a or the reverse brake clutch 628b of the forward/reverse switching mechanism 628 via the manual valves operated in accordance with the position of the range selector 644 operated by the driver, and the vehicle 1 can be made to travel in the forward direction or the reverse direction.

A crank angle sensor 650 is provided at an appropriate position such as near a camshaft (not shown) of the engine 610, and outputs a signal indicating the engine speed NE for each predetermined crank angle position of the piston. In the intake system, an absolute pressure sensor 652 is provided at an appropriate position downstream of the throttle valve, and outputs a signal proportional to an intake pipe absolute pressure (engine load) PBA.

The actuator of the DBW mechanism 618 is provided with a throttle opening sensor 654, and a signal proportional to the opening TH of the throttle valve is output by the amount of rotation of the actuator.

Further, an accelerator opening sensor 660 is provided in the vicinity of the accelerator pedal 616 to output a signal proportional to the accelerator opening AP corresponding to the depression amount (accelerator pedal operation amount) of the driver by the accelerator pedal 616, and a brake switch 662 is provided in the vicinity of the brake pedal 640 to output an on signal in accordance with the operation of the brake pedal 640 by the driver.

The output of the crank angle sensor 650 and the like is sent to the engine controller 666. The engine controller 666 includes a microcomputer including a Central Processing Unit (CPU), a Read Only Memory (ROM), a Random Access Memory (RAM), an Input/Output (I/O), and the like, and controls the operation of the DBW mechanism 618 based on these sensor outputs, and also controls fuel injection by the injector 620 and ignition timing by a spark plug and the like.

An NT sensor (rotation speed sensor) 670 is provided on the main shaft MS, and outputs a pulse signal indicating the rotation speed of the turbine/runner 624b, specifically, the rotation speed NT of the main shaft MS, more specifically, the rotation speed of the transmission input shaft (and the rotation speed of the input shaft of the forward clutch 628 a).

An NDR sensor (rotational speed sensor) 672 is provided at an appropriate position near the input pulley 626a of the CVT 626 and outputs a pulse signal corresponding to the rotational speed NDR of the input pulley 626a, in other words, the rotational speed of the output shaft of the forward clutch 628 a.

An NDN sensor (rotational speed sensor) 674 is provided at an appropriate position near the output pulley 626b and outputs a pulse signal indicating the rotational speed NDN of the output pulley 626b, specifically the rotational speed of the intermediate shaft CS, more specifically the rotational speed of the transmission output shaft.

A vehicle speed sensor (rotation speed sensor) 676 is provided near the gear 630b of the sub-shaft SS and outputs a pulse signal indicating the rotation speed and the rotation direction of the sub-shaft SS (specifically, a pulse signal indicating the vehicle speed V).

A range selector switch 680 is provided in the vicinity of the range selector 644, and outputs a signal corresponding to the R, N, D equivalent range selected by the driver.

A hydraulic pressure sensor 682 is disposed in an oil passage of the hydraulic pressure supply mechanism 646, and outputs a signal corresponding to the hydraulic pressure supplied to the output pulley 626 b. An oil temperature sensor 684 is disposed in the reservoir and outputs a signal corresponding to the oil temperature.

The output of the NT sensor 670 and the like is sent to the shift controller 690. Shift controller 690 also includes a microcomputer including a CPU, ROM, RAM, I/O, etc., and is configured to communicate with engine controller 666.

Based on these detection values, shift controller 690 controls forward/reverse switching mechanism 628, CVT 626, and torque converter 624 by exciting and deexciting the electromagnetic valves of hydraulic pressure supply mechanism 646.

That is, shift controller 690 calculates the friction coefficient between output pulley 626b and belt 626c according to a predetermined relational expression based on the driving state (input pulley rotation speed NDR, input torque, vehicle speed V, etc.) detected and calculated by various sensors, the shaft thrust force pressing input pulley 626a and output pulley 626b in the axial direction of main shaft MS and intermediate shaft CS, and the shaft force indicating the force with which main shaft MS and intermediate shaft CS cooperate with each other. Further, by performing feedback control of the shaft thrust force applied to the output pulley 626b using the calculated value of the friction coefficient, improvement of the power transmission efficiency and suppression of wear of the belt 626c are achieved.

6. Control method

Hereinafter, a control method according to a second embodiment of the present invention will be described in detail. The control method according to the present embodiment is mountable to the CVT vehicle 1 described above. Here, the acceleration/driving force control at the time of passing is described, but the present invention is applicable not only to the case of passing, but also to a situation where a sudden increase in driving force is expected.

6.1) Overtaking control

In this embodiment, the above-described cut-in scenario of fig. 3 is also considered. According to the present embodiment, during the state of the acceleration standby 302 and the acceleration standby 303 in fig. 3, the downshift of the CVT is performed more slowly than usual. Since the action plan is followed during the automatic driving as described above, the shift of the CVT during the acceleration standby may be performed more slowly than the usual shift. That is, vehicle control device 100 executes control for gradually increasing engine speed NE and gradually decreasing engine torque while shifting down the CVT so as to maintain the driving force and the vehicle speed constant. By performing the downshift in this manner, the feeling of strangeness of the occupant due to sudden changes in engine sound and vibration can be suppressed, and the feeling of the rubber belt can be suppressed as described later.

The control method according to the present embodiment is implemented by the vehicle control device 100 described above. The control function thereof may be realized by executing a program stored in a memory on a processor of the vehicle control device 100. The control method according to the present embodiment can be realized by the same control as the flow of fig. 4 described above, and thus the details of the flow are omitted.

6.2) accelerated Standby and accelerated execution

As illustrated in fig. 10 (a) to 10 (f), it is assumed that the accelerated standby is determined at time t 1. The vehicle control device 100 calculates a required driving force in advance, and gradually increases the engine speed NE while downshifting the CVT (c) and gradually decreases the engine torque (d) so as to maintain the driving force and the vehicle speed constant during the acceleration standby (b, f). For example, the engine torque may be reduced by reducing the throttle opening. In this way, vehicle control device 100 can control the CVT, the engine speed NE, and the engine torque so that the vehicle speed V and the driving force are maintained constant.

When actual acceleration is performed at time t2, vehicle control device 100 increases engine speed NE, engine torque, and ratio to target values and increases the driving force required for acceleration to required values. The engine torque can be raised by raising the throttle opening. At time t2, the CVT ratio is shifted down and the engine speed NE also increases, so the magnitude of the increase during the period until time t3 is small.

Conventionally, since the downshift is performed between time t2 and time t3 and the engine speed NE increases (broken lines in fig. 10 (c) and 10 (e)), the engine sound and vibration suddenly change between time t2 and time t3, which causes a large sense of discomfort to the occupant. In contrast, according to the present embodiment, since the downshift is performed gradually during the acceleration standby, the engine speed NE changes more gradually, and the sense of incongruity as in the conventional art is greatly reduced. Further, at time t2, the CVT ratio is shifted down and the engine speed NE is also increased, so acceleration can be performed quickly.

6.3) accelerated termination

As illustrated in fig. 11 (a) to 11 (f), it is assumed that the acceleration standby is determined at time t1, but the acceleration is determined to be stopped at time t 4. In this case, the CVT is downshifted before time t4, and the engine speed NE is increased to cause the engine to run fasterThe engine torque decreases, and therefore the vehicle control device 100 performs control so as to gradually return them to the original state. According to the present embodiment, the engine speed NE is increased by Δ NE when the engine speed NE is increased in proportion to the engine speed_UPSmall Δ NE_DOWNThe gear is shifted up in a descending manner so as to maintain the driving force and the vehicle speed constant. By gradually decreasing the engine speed NE more slowly than when it is increased, the sense of incongruity of the occupant can be eliminated.

6.4) suppression of rubber Belt feel

In the conventional control shown by the broken line in fig. 12 (a) to 12 (f), acceleration is performed at time t2 to increase the engine speed NE and the engine torque, and downshift is performed. However, as shown by the broken line in fig. 12 (d), when the engine torque reaches the upper limit at time point t3, the driving force is compensated only by the ratio. Therefore, the engine speed NE is increased by downshifting the ratio between time t3 and time t4, and the acceleration is performed. Between the time point t3 and the time point t4, the rise in the engine rotation speed NE is greater than the rise in the vehicle speed V, and a rubber belt feeling, which is a feeling that the vehicle speed does not rise with respect to a large engine sound, is generated.

In contrast, according to the present embodiment shown by the solid line in fig. 12 (a) to 12 (f), the downshift is performed to such an extent that there is no sense of incongruity during the acceleration standby, and the engine speed NE is increased, so that a rubber belt feel can be avoided in which only the engine speed NE is rapidly increased.

6.5) downhill control

The control method according to the present embodiment is applicable as long as the condition of downshift is predicted. For example, when it is recognized from the map information that there is a downward slope ahead, the sense of incongruity as in the conventional art can be greatly reduced by performing the smooth gear shift described above before the downward slope is reached. Since the flow of the downhill control in the present embodiment is basically the same as that shown in fig. 7, the description thereof will be omitted, and the state of the downhill control will be described with reference to fig. 13 (a) to 13 (e).

As illustrated in fig. 13 (a) to 13 (e), it is assumed that the downhill prediction is determined at time t 1. The vehicle control device 100 calculates the required driving force in advance, and gradually increases the engine speed NE by a downshift between time t1 and time t2 (b) and gradually decreases the engine torque (c). For example, the engine torque may be decreased by decreasing the throttle opening. Since the engine torque decreases even if the engine speed NE increases, the vehicle control device 100 can control the vehicle speed V to be constant.

When the downhill control is started at time t2, the vehicle control device 100 executes Fuel Cut (FC) control for stopping the supply of fuel to the engine EG based on the braking force determined based on the action plan and causing the engine to brake. At this time, the variator ratio of the CVT and the engine speed NE do not vary greatly.

Conventionally, the engine speed NE is increased between time t2 and time t3 (broken line in fig. 13 b), and the downshift (d) is performed. Therefore, the engine sound and vibration change suddenly, which causes a large discomfort to the occupant. In contrast, according to the present embodiment, since the downshift is performed during the downhill prediction, the engine speed NE changes more gradually, and the sense of incongruity as in the conventional art is greatly reduced.

7. Effect

As described above, according to the embodiments and examples of the present invention, when the automatic transmission vehicle has time before the change timing of the required driving force during automatic driving, by executing the downshift of gradually increasing the engine speed while keeping the vehicle speed constant and gradually decreasing the engine torque during the period before the change timing, it is possible to reduce the vibration, noise, and shift shock caused by the downshift when the required driving force actually changes.