CN114347992A

CN114347992A - Vehicle controller, vehicle control program, storage medium, and vehicle control method

Info

Publication number: CN114347992A
Application number: CN202111101361.1A
Authority: CN
Inventors: 吉田征司
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2020-09-28
Filing date: 2021-09-18
Publication date: 2022-04-15
Anticipated expiration: 2041-09-18
Also published as: JP2022054702A; DE102021122851A1; CN114347992B; JP7331814B2

Abstract

A vehicle controller, a vehicle control program, a storage device, and a vehicle control method are provided. The second mode controls the driving force and the braking force of the vehicle using one of the operation amount of the accelerator pedal and the operation amount of the brake pedal. The first braking force calculation process calculates a first braking force using the operation amount of the brake pedal. The second braking force calculation process calculates a second braking force using the operation amount of the second mode pedal. The activation process activates the second mode when the first braking force is greater than or equal to the second braking force.

Description

Vehicle controller, vehicle control program, storage medium, and vehicle control method

Technical Field

The present disclosure relates to a vehicle controller, a vehicle control program, a storage medium, and a vehicle control method.

Background

Japanese laid-open patent publication No. 2010-284979 discloses a controller for a vehicle that controls traveling of the vehicle by switching between two traveling modes (i.e., a normal mode and a single-pedal mode). The normal mode is a running mode in which the driving force of the vehicle is controlled using the operation amount of the accelerator pedal and the braking force of the vehicle is controlled using the operation amount of the brake pedal. The single pedal mode is a running mode in which the driving force and the braking force of the vehicle are controlled using the operation amount of the accelerator pedal.

Even in the case where a request for switching from the normal mode to the single-pedal mode is received, if the occupant depresses the brake pedal at the time point of issuing the switching request, the controller does not switch to the single-pedal mode.

Subsequently, when the occupant releases the brake pedal and starts depressing the accelerator pedal and the operation amount of the accelerator pedal reaches a given amount, the controller starts the single-pedal mode. The controller does not generate a constant braking force in the vehicle until the operation amount of the accelerator pedal reaches a given amount.

In the technique of the above-described document, regardless of the request to switch to the single-pedal mode, the operation amount of the accelerator pedal remains unreflected on the braking force of the vehicle until the operation amount of the accelerator pedal reaches a given amount after the occupant switches to the accelerator pedal. Thus, the amount of deceleration of the vehicle during this period may be significantly different from the amount of deceleration intended by the occupant.

In the technique of this document, unless the operation amount of the accelerator pedal becomes larger than a given amount, the operation amount of the accelerator pedal remains unreflected on the driving force of the vehicle. Therefore, the amount of acceleration of the vehicle continues to differ from the amount of acceleration intended by the occupant, in the same manner as the amount of deceleration of the vehicle.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

Aspects of the present disclosure will now be described.

Aspect 1: a vehicle controller according to an aspect of the present disclosure is configured to control travel of a vehicle using a first mode and a second mode. The first mode controls the driving force of the vehicle using the operation amount of the accelerator pedal and controls the braking force of the vehicle using the operation amount of the brake pedal. The second mode controls the driving force and the braking force of the vehicle using one of the operation amount of the accelerator pedal and the operation amount of the brake pedal. The vehicle controller is configured to execute a first braking force calculation process, a second braking force calculation process, and an activation process when a request to activate the second mode is received in a situation where an operation amount of a brake pedal is greater than zero during control of the vehicle in the first mode. The first braking force calculation process calculates a first braking force, which is a target value of the braking force in the first mode, using the operation amount of the brake pedal. The second braking force calculation process calculates a second braking force using an operation amount of a second mode pedal for the second mode, the second braking force being a target value of a braking force for a case where the braking force of the vehicle is controlled in the second mode. The activation process activates the second mode when the first braking force is greater than or equal to the second braking force.

In this configuration, the second mode is activated as long as the condition that the first braking force is greater than or equal to the second braking force is satisfied. This restricts a situation where, for example, the running state of the vehicle different from the running state of the vehicle desired by the occupant continues. In this configuration, the second mode is not activated when the second braking force is greater than the first braking force. This prevents the vehicle from being suddenly braked, for example, at the moment when the second mode is activated.

Aspect 2: in the vehicle controller according to aspect 1, the second mode pedal is an accelerator pedal. The vehicle controller is configured to execute the transition process when a request to activate the second mode is received in a situation where an operation amount of a brake pedal is greater than zero during control of the vehicle in the first mode. The transition process controls the braking force of the vehicle to the first braking force until the first braking force falls below the second braking force regardless of whether the second mode is activated.

In this configuration, the braking force of the vehicle is not rapidly changed from the first braking force to the second braking force when the second mode is activated, regardless of whether the occupant continues to operate the brake pedal. Therefore, the braking force of the vehicle is prevented from suddenly increasing without the occupant's operation.

Aspect 3: the vehicle equipped with the vehicle controller according to aspect 2 includes: a hydraulic brake device that generates braking force using hydraulic pressure; and a generator that generates a regenerative braking force corresponding to the amount of power generation. The vehicle controller is configured to control the vehicle such that at least the hydraulic braking device is used to provide a first braking force that is obtained when the vehicle is controlled in the first mode. The vehicle controller is configured to control the vehicle such that only the generator is used to provide the second braking force that is obtained when the vehicle is controlled in the second mode. The vehicle controller is configured to control the vehicle such that the hydraulic brake device is used to provide at least a part of the first braking force, even when the second mode is activated, in the transition process.

In this configuration, during the transition process, whether the second mode is activated or not, at least a portion of the braking force of the vehicle is provided by the hydraulic pressure. Therefore, the first braking force is easily provided regardless of the speed of the vehicle or the like.

Aspect 4: the vehicle equipped with the vehicle controller according to aspect 2 includes: a hydraulic brake device that generates braking force using hydraulic pressure; and a generator that generates a regenerative braking force corresponding to the amount of power generation. The vehicle controller is configured to control the vehicle such that at least the hydraulic braking device is used to provide a first braking force that is obtained when the vehicle is controlled in the first mode. The vehicle controller is configured to control the vehicle such that only the generator is used to provide the second braking force that is obtained when the vehicle is controlled in the second mode. In the transition process, the vehicle controller is configured to control the vehicle such that the generator generates the braking force of the maximum value, and the hydraulic braking device compensates for a difference between the first braking force and the maximum value, even if the second mode is activated when the first braking force is greater than the maximum value of the regenerative braking force allowed in the generator at the running speed of the vehicle.

In this configuration, at least a portion of the first braking force is provided by the generator during the transition process. Therefore, even if the vehicle is controlled by the second mode in which the braking force of the vehicle is provided only by the generator, the transition to the control in the second mode is quickly performed after the transition process is ended. When the generator cannot provide the first braking force, the hydraulic pressure is used in combination. Therefore, the braking force will not become insufficient.

Aspect 5: another aspect of the present disclosure provides a vehicle control program that causes a processor to execute a control process to control travel of a vehicle using a first mode and a second mode. The control process includes: controlling a driving force of the vehicle using an operation amount of an accelerator pedal and controlling a braking force of the vehicle using an operation amount of a brake pedal in the first mode; controlling a driving force and a braking force of the vehicle using one of an operation amount of an accelerator pedal and an operation amount of a brake pedal in the second mode; and executing a first braking force calculation process, a second braking force calculation process, and an activation process when a request to activate the second mode is received in a situation where an operation amount of a brake pedal is greater than zero during control of the vehicle in the first mode. The first braking force calculation process calculates a first braking force, which is a target value of the braking force in the first mode, using the operation amount of the brake pedal. The second braking force calculation process calculates a second braking force that is a target value of the braking force for a case where the braking force of the vehicle is controlled in the second mode, using an operation amount of a second mode pedal for the second mode. The activation process activates the second mode when the first braking force is greater than or equal to the second braking force.

Aspect 6: there is provided a storage medium storing a program according to aspect 5 to cause a processor to execute a control process. The storage medium may be provided as a non-transitory computer-readable storage medium.

Aspect 7: another aspect of the present disclosure provides a vehicle controller configured to control travel of a vehicle using a first mode and a second mode. The first mode controls the driving force of the vehicle using the operation amount of the accelerator pedal and controls the braking force of the vehicle using the operation amount of the brake pedal. The second mode controls the driving force and the braking force of the vehicle using one of the operation amount of the accelerator pedal and the operation amount of the brake pedal. The vehicle controller is configured to execute the first driving force calculation process, the second driving force calculation process, and the activation process when a request to activate the second mode is received in a situation where an operation amount of an accelerator pedal is greater than zero during control of the vehicle in the first mode. The first driving force calculation process calculates a first driving force, which is a target value of the driving force in the first mode, using the operation amount of the accelerator pedal. The second driving force calculation process calculates the second driving force using the operation amount of a second mode pedal used for the second mode. The second driving force is a target value of the driving force for the case where the driving force of the vehicle is controlled in the second mode. The activation process activates the second mode when the first driving force is greater than or equal to the second driving force.

In this configuration, the second mode is activated as long as the condition that the first driving force is greater than or equal to the second driving force is satisfied. This restricts a situation where, for example, the running state of the vehicle different from the running state of the vehicle desired by the occupant continues. In this configuration, when the second driving force is larger than the first driving force, the second mode is not activated. This prevents the vehicle from being suddenly accelerated, for example, at the moment the second mode is activated.

Aspect 8: a vehicle control method including various processes according to any one of aspects 1 to 4 may be provided.

Aspect 9: a vehicle control method including various processes according to aspect 7 may be provided. Further, a program that causes a processor to execute various processes described in aspect 7 may be provided. Further, a storage medium storing a program that causes a processor to execute various processes described in aspect 7 may be provided.

Other features and aspects will be apparent from the following detailed description, the accompanying drawings, and the claims.

Drawings

Fig. 1 is a schematic diagram showing the configuration of a vehicle.

Fig. 2 is a diagram showing an example of a single pedal map (map).

Fig. 3 is a flowchart showing a procedure of a single-pedal process of changing the travel mode of the vehicle from the normal mode to the single-pedal mode.

Fig. 4 is a flowchart showing a procedure of the transition braking control in step S170 of fig. 2.

Fig. 5 is a time chart including parts (a) to (c), showing an example of temporal changes in variables in the single-pedal process.

Like reference numerals refer to like elements throughout the drawings and detailed description. The figures may not be drawn to scale and the relative sizes, proportions and depictions of elements in the figures may be exaggerated for clarity, illustration and convenience.

Detailed Description

This description provides a thorough understanding of the described methods, devices, and/or systems. Modifications and equivalents of the described methods, apparatus, and/or systems will be apparent to those of ordinary skill in the art. The order of operations is exemplary, except that operations must occur in a particular order, and the order of operations may be altered in a manner apparent to those of ordinary skill in the art. Descriptions of functions and constructions well known to those of ordinary skill in the art may be omitted.

The exemplary embodiments may have different forms and are not limited to the described examples. The described examples, however, are thorough and complete, and will convey the full scope of the disclosure to those skilled in the art.

A vehicle controller employed in a hybrid vehicle 500 according to an embodiment will now be described with reference to fig. 1 to 5.

First, a schematic configuration of the hybrid vehicle 500 will be described.

As shown in fig. 1, a hybrid vehicle 500 (hereinafter referred to as a vehicle 500) includes an internal combustion engine 70, a first motor generator 71 (hereinafter referred to as a first MG 71), a second motor generator 72 (hereinafter referred to as a second MG 72), a planetary gear mechanism 40, a reduction gear 50, a differential 61, and driven wheels 62.

The internal combustion engine 70, the first MG 71, and the second MG 72 serve as drive sources of the vehicle 500. The first MG 71 and the second MG 72 each function as a motor and a generator. Although not shown in the drawings, the first MG 71 and the second MG 72 are electrically connected to a battery via an inverter.

The internal combustion engine 70 and the first MG 71 are coupled to the planetary gear mechanism 40. The planetary gear mechanism 40 includes a sun gear 41, a ring gear 42, pinion gears 43, and a carrier 44. The sun gear 41 is an external gear. The ring gear 42 is an internal gear. The ring gear 42 is rotatable coaxially with the sun gear 41. A pinion gear 43 that meshes with the sun gear 41 and the ring gear 42 is arranged between the sun gear 41 and the ring gear 42. Each pinion 43 is supported by a carrier 44. The carrier 44 is rotatable coaxially with the sun gear 41.

The sun gear 41 is coupled to a rotation shaft of the first MG 71. The carrier 44 is coupled to the crankshaft 34, and the crankshaft 34 is an output shaft of the internal combustion engine 70. The ring gear 42 is coupled to the drive shaft 60. The drive shaft 60 is coupled to the second MG 72 via the reduction gear 50. The reduction gear 50 reduces the torque of the second MG 72 and transmits the reduced torque to the drive shaft 60. Further, the drive shaft 60 is coupled to a driven wheel 62 via a differential 61. The differential 61 allows a rotational speed difference to occur between the left and right driven wheels 62.

The internal combustion engine 70 and the first MG 71 are capable of transmitting power to each other via the planetary gear mechanism 40. When the output torque of the internal combustion engine 70 is given to the first MG 71, the first MG 71 functions as a generator. When the first MG 71 functions as a motor, the crankshaft 34 can be rotated by the output torque of the first MG 71.

When the second MG 72 functions as a generator during deceleration of the vehicle 500, regenerative braking force is generated in the vehicle 500 according to the amount of electric power generated by the second MG 72. When the second MG 72 functions as a motor, the output torque of the second MG 72 is given to the driven wheels 62 via the reduction gear 50, the drive shaft 60, and the differential 61.

The vehicle 500 includes a hydraulic brake device 80. The hydraulic brake device 80 includes a hydraulic circuit 81 and a brake mechanism 82. The hydraulic circuit 81 generates hydraulic pressure. The hydraulic circuit 81 is connected to a brake mechanism 82. The brake mechanism 82 operates in accordance with the hydraulic pressure of the hydraulic circuit 81. When the hydraulic pressure generated by the hydraulic circuit 81 increases, the friction material of the brake mechanism 82 is pressed against the rotor that rotates integrally with the driven wheel 62. This causes the brake mechanism 82 to apply a braking force to the driven wheel 62. In this way, the hydraulic brake device 80 generates braking force using hydraulic pressure.

The vehicle 500 includes an accelerator pedal 94 and a brake pedal 95. The accelerator pedal 94 and the brake pedal 95 are foot pedals that are depressed by the occupant.

The vehicle 500 includes an accelerator sensor 21, a brake sensor 22, and a vehicle speed sensor 23. The accelerator sensor 21 detects an accelerator operation amount ACCP, which is a depression amount of the accelerator pedal 94. The brake sensor 22 detects a brake operation amount BKP, which is a depression amount of the brake pedal 95. The vehicle speed sensor 23 detects a vehicle speed SP, which is a running speed of the vehicle 500.

The vehicle 500 includes a mode selection switch 97. The mode selector switch 97 is located in the passenger compartment. The mode selection switch 97 is a push button switch pressed by the occupant. The mode selection switch 97 is used to set the running mode of the vehicle 500 to a normal mode or a single-pedal mode, which will be described later. In the present embodiment, the travel mode is switched from one of the normal mode and the single pedal mode to the other every time the mode selection switch 97 is pressed.

The vehicle 500 includes a display 99. The display 99 is located in the passenger compartment. The display 99 is capable of displaying various types of information. For example, the display 99 uses icons and messages to indicate whether the travel mode of the vehicle 500 is the normal mode or the single-pedal mode.

The control configuration of the vehicle 500 will now be described.

First, an overview of the controller 100 will be described.

The vehicle 500 includes a controller 100. The controller 100 includes one or more processors that perform various processes according to computer programs (software). The controller 100 may be a Circuit including one or more dedicated hardware circuits (such as an Application Specific Integrated Circuit (ASIC)) that perform at least a portion of the various processes, or a combination thereof. The processor includes a CPU102 and memories, such as RAM and ROM 104. The memory stores program codes (vehicle control programs) or instructions configured to cause the CPU102 to execute processing (control processing). The memory or computer-readable medium includes any type of media or non-transitory computer-readable storage media that can be accessed by a general purpose computer as well as a special purpose computer.

The controller 100 receives detection signals of various sensors mounted on the vehicle 500. More specifically, the controller 100 receives detection signals of the following parameters:

an accelerator operation amount ACCP detected by the accelerator sensor 21;

a brake operation amount BK detected by the brake sensor 22; and

the vehicle speed SP detected by the vehicle speed sensor 23.

Further, when the occupant operates the mode selection switch 97, the controller 100 receives a change request signal G for the running mode of the vehicle 500.

The CPU102 controls the running of the vehicle 500 using the detection results of various sensors. The CPU102 controls the running of the vehicle 500 using two running modes, i.e., a normal mode (first mode) and a single-pedal mode (second mode). The normal mode (first mode) is a running mode in which the driving force of the vehicle 500 is controlled using the accelerator operation amount ACCP and the braking force of the vehicle 500 is controlled using the brake operation amount BKP. The single-pedal mode (second mode) is a running mode in which the driving force and the braking force of the vehicle 500 are controlled using the operation amount of the accelerator operation amount ACCP. That is, in the present embodiment, the accelerator pedal 94 is a second mode pedal, which is used in the second mode. In the present embodiment, the CPU102 controls the vehicle 500 such that the hydraulic brake device 80 and the second MG 72 provide braking force for controlling the vehicle 500 in the normal mode. The CPU102 controls the vehicle 500 such that only the second MG 72 provides a braking force for controlling the vehicle 500 in the single-pedal mode.

In the normal mode, the CPU102 controls the driving force of the vehicle 500 using a normal drive map stored in the ROM 104. The conventional drive map shows the relationship between the accelerator operation amount ACCP and the target value of the driving force. In the conventional drive map, as the accelerator operation amount ACCP increases, the target value of the drive force increases. In order to control the driving force of the vehicle 500, the CPU102 refers to the latest accelerator operation amount ACCP and the normal drive map to calculate a target value of the driving force corresponding to the accelerator operation amount ACCP in the normal drive map. The CPU102 controls the output of the internal combustion engine 70 and the torques of the first MG 71 and the second MG 72 so that the driving force of the vehicle 500 has a target value. The CPU102 basically controls the first MG 71 and the second MG 72 by controlling the inverter.

In the normal mode, the CPU102 controls the braking force of the vehicle 500 using a normal brake map stored in the ROM 104. The conventional brake map shows the relationship between the brake operation amount BKP and the target value of the braking force. In the conventional drive map, as the brake operation amount BKP increases, the target value of the braking force increases. To control the braking force of the vehicle 500, the CPU102 calculates a target value of the braking force corresponding to the brake operation amount BKP in the regular brake map with reference to the latest brake operation amount BKP and the regular brake map. The CPU102 distributes the calculated target values to the hydraulic brake device 80 and the second MG 72 in a predetermined distribution manner. In the present embodiment, the CPU102 distributes approximately two-thirds of the target value of the braking force calculated by the conventional brake map to the hydraulic brake device 80, and distributes approximately one-third of the target value to the second MG 72. The CPU102 sets the amount of braking force allocated to the hydraulic brake device 80 to a target value QHY of the braking force of the hydraulic brake device 80, and controls the hydraulic pressure of the hydraulic brake device 80 using the target value QHY. Further, the CPU102 sets the amount of braking force allocated to the second MG 72 as a target value QMG of the regenerative braking force of the second MG 72, and controls the torque of the second MG 72 using the target value QMG.

In the single-pedal mode, the CPU102 controls the driving force and the braking force of the vehicle 500 using a single-pedal map stored in the ROM 104. As shown in fig. 2, the single-pedal map shows the relationship between the accelerator operation amount ACCP and the target values of the driving force and the braking force of the vehicle 500. In the single pedal map, the neutral point CV, the acceleration region CA, and the deceleration region CD are defined within a range of possible values of the accelerator operation amount ACCP. At the neutral point CV, the target value of the driving force and the target value of the braking force are zero. In the acceleration region CA, the accelerator operation amount ACCP is larger than the value of the neutral point CV. In the acceleration region CA, as the accelerator operation amount ACCP increases, the target value of the driving force increases. In the deceleration region CD, the accelerator operation amount ACCP is smaller than the value of the neutral point CV. In the deceleration region CD, as the accelerator operation amount ACCP decreases, the target value of the braking force increases. A single-pedal map is prepared for each vehicle speed SP.

To control the vehicle 500 in the single-pedal mode, the CPU102 refers to the latest accelerator operation amount ACCP and the single-pedal map corresponding to the latest vehicle speed SP. The CPU102 calculates a target value of the braking force or a target value of the driving force corresponding to the accelerator operation amount ACCP in the single pedal map. When the accelerator operation amount ACCP is a value in the acceleration region CA, the CPU102 calculates a target value of the driving force corresponding to the accelerator operation amount ACCP. The CPU102 controls the output of the internal combustion engine 70 and the torques of the first MG 71 and the second MG 72 so that the driving force of the vehicle 500 has a target value. When the accelerator operation amount ACCP is a value in the deceleration region CD, the CPU102 calculates a target value of the braking force corresponding to the accelerator operation amount ACCP. The CPU102 controls the torque of the second MG 72 so that the braking force of the vehicle 500 has a target value.

The CPU102 can execute the mode change process. That is, when the CPU102 receives the change request signal G in the case where the running mode of the vehicle 500 is the normal mode, the process of changing the running mode to the single-pedal mode is executed as the mode change process. When the CPU102 receives the change request signal G in the case where the running mode of the vehicle 500 is the single-pedal mode, a process of changing the running mode to the normal mode is executed as the mode change process. The CPU102 basically processes the change request signal G as a signal that activates the single pedal mode or the normal mode. For example, in this activation, activation of the single pedal mode refers to completion of preparation for control executed by the CPU102 in the single pedal mode.

In the mode change process, a specific procedure of the single pedal process of changing the running mode of the vehicle from the normal mode to the single pedal mode will now be described.

The CPU102 executes each step of the single pedal process by executing a program stored in the ROM 104. When the CPU102 controls the vehicle 500 in the normal mode before starting the single-pedal process, the CPU102 causes the display 99 to display a message indicating that the current running mode of the vehicle 500 is the normal mode. The one-pedal process is started when the CPU102 receives the change request signal G in a case where the running mode of the vehicle 500 is the normal mode.

As shown in fig. 3, when the single pedal process is started, the CPU102 executes the process of step S100. In step S100, the CPU102 determines whether the brake operation amount BKP is greater than zero. The CPU102 makes the determination in step S100 by referring to the latest brake operation amount BKP. When the brake operation amount BKP is zero (step S100: no), the CPU102 advances the process to step S400.

In step S400, the CPU102 determines whether the accelerator operation amount ACCP is greater than zero. The CPU102 makes the determination in step S400 by referring to the latest accelerator operation amount ACCP. When the accelerator operation amount ACCP is zero (no in step S400), the CPU102 advances the process to step S410.

In step S410, CPU102 causes display 99 to display a message indicating that the running mode of vehicle 500 cannot be changed to the single-pedal mode. To change the travel mode to the single-pedal mode, the CPU102 causes the display 99 to display a message indicating that the mode selection switch 97 needs to be operated if the accelerator pedal 94 or the brake pedal 95 is depressed. Subsequently, the CPU102 ends a series of steps of the single pedal process.

In step S400, when the accelerator operation amount ACCP is greater than zero (step S400: yes), the CPU102 advances the process to step S210. When the determination at step S400 is yes, the CPU102 takes the change request signal G that has been received as a signal requesting activation of the single-pedal mode in the case where the vehicle 500 is controlled in the normal mode and in the case where the accelerator operation amount ACCP is greater than zero.

In step S210, the CPU102 starts control in the single pedal mode after the single pedal mode is activated. Further, the CPU102 causes the display 99 to display a message indicating that the current running mode of the vehicle 500 is the one-pedal mode. Subsequently, the CPU102 ends a series of steps of the single pedal process.

In step S100, when the brake operation amount BKP is greater than zero (step S100: yes), the CPU102 advances the process to step S110. When the determination at step S100 is yes, the CPU102 takes the received change request signal G as a signal requesting activation of the single-pedal mode in the case where the vehicle 500 is controlled in the normal mode and in the case where the brake operation amount BKP is greater than zero. When the determination of step S100 is yes, the CPU102 continues to control the vehicle 500 in the normal mode until the process of step S170 (described later) is executed.

In step S110, the CPU102 determines whether the accelerator operation amount ACCP is zero. When the determination at step S100 described above is yes, the accelerator operation amount ACCP is likely to be zero, but is not always zero. The determination at step S110 is a process of checking whether the accelerator operation amount ACCP is zero. The CPU102 executes the process of S110 by referring to the latest accelerator operation amount ACCP. When the accelerator operation amount ACCP is greater than zero (step S110: no), the CPU102 advances the process to step S410, which has been described above. When the accelerator operation amount ACCP is zero (yes in step S110), the CPU102 advances the process to step S120.

In step S120, the CPU102 causes the display 99 to display a message indicating that the process of starting the single-pedal mode is being executed. Further, the CPU102 causes the display 99 to display a message prompting to continue depressing the brake pedal 95. After executing the process of step S120, the CPU102 advances the process to step S130.

In step S130, the CPU102 calculates a first braking force a 1. The first braking force a1 is a target value of the braking force in the normal mode. The CPU102 refers to the latest brake operation amount BKP and a conventional brake map stored in the ROM 104. The CPU102 calculates a target value of the braking force corresponding to the latest brake operation amount BKP in the normal brake map as the first braking force a 1. After calculating the first braking force a1, the CPU102 advances the process to step S140. The process of step S130 is a first braking force calculation process.

In step S140, the CPU102 calculates the second braking force a 2. More specifically, the CPU102 calculates a target value of the braking force for the case where the current braking force of the vehicle 500 is controlled in the single-pedal mode as the second braking force a 2. In detail, the CPU102 calculates a target value of the braking force in the single pedal mode for the case where the accelerator operation amount ACCP is zero. The ROM 104 stores a calculation map showing the braking force in the single-pedal mode when the accelerator operation amount ACCP is zero for each vehicle speed SP. The braking force defined in the calculation map has the maximum value of the regenerative braking force permitted in the second MG 72 at each vehicle speed SP.

To calculate the second braking force a2, the CPU102 refers to the latest vehicle speed SP. The CPU102 refers to the calculation map stored in the ROM 104. The CPU102 calculates the regenerative braking force corresponding to the latest vehicle speed SP in the calculation map as the second braking force a 2. After calculating the second braking force a2, the CPU102 advances the process to step S150. The process of step S140 is a second braking force calculation process.

In step S150, the CPU102 determines whether the first braking force a1 is greater than or equal to the second braking force a 2. More specifically, the CPU102 compares the first braking force a1 calculated in step S130 with the second braking force a2 calculated in step S140. When the first braking force a1 is smaller than the second braking force a2 (step S150: no), the CPU102 advances the process to step S300.

In step S300, the CPU102 determines whether the elapsed time from the start of the one-pedal process is greater than or equal to a predetermined given period H. In the present embodiment, the given period H is defined as the following duration. The maximum value of the regenerative braking force defined in the calculation map is referred to as the maximum braking force. The general operating speed obtained by depressing the brake pedal 95 is referred to as a depression speed. The given period H is set to be slightly longer than the time at which the first braking force a1 becomes the maximum braking force in accordance with the depression of the brake pedal 95 from the start of depression of the brake pedal 95 when the brake pedal 95 is operated at the depression speed.

When the elapsed time from the start of the one-pedal process is less than the given period H (step S300: NO), the CPU102 returns to the process of S130. Then, the CPU102 executes the processing of step S130, step S140, and step S150 again. When the determination of step S150 remains no, the CPU102 repeats the processing of steps S130, S140, and S150 until the elapsed time since the start of the one-pedal process reaches the given period H. When the elapsed time becomes greater than or equal to the given period H while the determination of step S150 does not become yes (step S300: yes) during the process of steps S130 to S150 and S300 is repeated, the CPU102 proceeds to the process of step S310. For example, when the brake pedal 95 is kept slightly depressed, the determination of step S300 becomes yes. The determination of step S300 becomes yes even when the occupant releases the brake pedal 95 after the single-pedal process is started.

In step S310, CPU102 causes display 99 to display a message indicating that the running mode of vehicle 500 cannot be changed to the single-pedal mode. Further, the CPU102 causes the display 99 to indicate that the travel mode cannot be changed to the single-pedal mode due to insufficient depression of the brake pedal 95.

When the determination of step S150 becomes yes before the elapsed time from the start of the single-pedal process reaches the given period H, that is, when the first braking force a1 becomes greater than or equal to the second braking force a2 (step S150: yes), the CPU102 advances the process to step S160. One of the cases where step S150 becomes yes is a case where the brake operation amount BKP is sufficiently large at the time point when the single-pedal process is started. Another case of the cases where step S150 becomes yes is a case where the brake operation amount BKP is gradually increased to be sufficiently large after the start of the one-pedal process.

In step S160, the CPU102 activates the single pedal mode. That is, if the occupant releases the brake pedal 95 and starts depressing the accelerator pedal 94, the CPU102 makes preparation so as to execute control of the driving force or the braking force based on the accelerator operation amount ACCP. At the time point when step S160 is executed, the brake pedal 95 is still depressed, and therefore control of the driving force or braking force in the single pedal mode has not been executed. Further, in step S160, the CPU102 causes the display 99 to display a message indicating that preparation for traveling in the single-pedal mode has been made. Further, the CPU102 causes the display 99 to display a message indicating that traveling in the single-pedal mode is started by releasing the brake pedal 95. After executing the process of step S160, the CPU102 advances the process to step S170. The process of step S160 is an activation process.

In step S170, the CPU102 cancels the vehicle control in the normal mode and starts the transition process. The transition process controls the braking force of the vehicle 500 to the first braking force a1 until the first braking force a1 falls below the second braking force a 2. The transition process also increases the target value QMG of the regenerative braking force of the second MG 72 toward the second braking force a 2. In the transition process, the CPU102 repeatedly calculates the target values QMG of the regenerative braking forces of the first braking force a1, the second braking force a2, and the second MG 72. Details of the transition processing will be described later. After executing the transition processing, the CPU102 advances the processing to step S180.

In step S180, the CPU102 determines whether the first braking force a1 is smaller than the second braking force a 2. More specifically, the CPU102 refers to the latest first braking force a1 and the latest second braking force a2 calculated in the transition process. When the first braking force A1 is greater than or equal to the second braking force A2 (step S180: NO), the CPU102 executes the process of step S180 again. The CPU102 repeats the process of step S180 until the first braking force a1 becomes smaller than the second braking force a 2. When the first braking force A1 becomes smaller than the second braking force A2 (step S180: YES), the CPU102 advances the process to step S190. When the reduction in the brake operation amount BKP reduces the first braking force a1 such that the first braking force a1 eventually falls below the second braking force a2, step S180 becomes yes.

In step S190, the CPU102 ends the transition process. Subsequently, the CPU102 advances the process to step S200.

In step S200, the CPU102 determines whether the target value QMG of the regenerative braking force of the second braking force a2 that is calculated last in the transition process is equal to the value of the second braking force a2 that is calculated last in the transition process. When the determination is yes (step S200: yes), the CPU102 skips the process of step S205 (described later) and advances the process to step S210. When the target value QMG of the regenerative braking force of the second braking force a2 reaches the second braking force a2 during execution of the transition process, the determination of step S200 becomes yes. In this case, the braking force of the vehicle 500 in the single-pedal mode may be provided only by the regenerative power of the second MG 72 from the time point when the transition process ends.

In step S210, the CPU102 starts control in the single-pedal mode. Further, the CPU102 causes the display 99 to display a message indicating that the current running mode is the one-pedal mode. Subsequently, the CPU102 ends a series of steps of the one-pedal process (shift one-pedal mode process).

When the determination of step S200 is no (i.e., when the target value QMG of the regenerative braking force of the second braking force a2 that is calculated last in the transition process is smaller than the value of the second braking force a2 that is calculated last in the transition process), the CPU102 executes the process of step S205 before executing the process of step S210. When the target value QMG of the regenerative braking force of the second braking force a2 does not reach the second braking force a2 during the execution period of the transition process (S170 to S190), the determination of step S200 becomes no. When the execution period of the transition processing is short (for example, when the passenger releases the brake pedal 95 immediately after the transition processing is started), the determination of step S200 is no. In the case where the determination at step S200 is no, the braking force of the vehicle 500 in the single-pedal mode cannot be provided by only the regenerative power of the second MG 72 at the time point when the transition process is ended. Therefore, the CPU102 executes the process of step S205.

In step S205, the CPU102 executes the braking force increasing process. This process quickly increases the proportion of the braking force in the single pedal mode that is provided by the regenerative braking force of the second MG 72, while controlling the braking force of the vehicle 500 to the braking force in the single pedal mode. In this process, in the same manner as the transition process, the hydraulic brake device 80 compensates for the difference between the target value of the braking force of the single pedal mode and the target value QMG of the regenerative braking force of the second MG 72.

More specifically, the CPU102 repeats the following increase braking control in the braking force increase processing of step S205. The execution cycle of the increase braking control is the same as the execution cycle of the transition braking control of the transition processing in step S170, which will be described later. In the increase braking control, the CPU102 first calculates a target value of the braking force in the single-pedal mode using the single-pedal map in the same manner as the control of the vehicle 500 in the single-pedal mode. Next, the CPU102 sets the latest target value QMG to a value obtained by adding a predetermined given additional value to the target value of the regenerative braking force set for the second MG 72 during the previous execution of the added braking control. The given additional value will be described later in relation to the conversion process. In the case where the added braking control is executed for the first time after the braking force increase process is started, the CPU102 regards the target value of the regenerative braking force that was last set for the second MG 72 when the transition process was executed before the current braking force increase process was started as the previous target value. The CPU102 calculates a target value QMG of the regenerative braking force of the second MG 72, and then calculates a target value QHY of the braking force of the hydraulic brake device 80. More specifically, the CPU102 sets the target value QHY of the braking force of the hydraulic brake device 80 to a value obtained by subtracting the target value QMG of the regenerative braking force of the second MG 72 from the target value of the braking force in the single pedal mode. The CPU102 controls the second MG 72 using the target value QMG of the regenerative braking force of the second MG 72, and controls the braking force of the hydraulic brake device 80 using the target value QHY of the braking force of the hydraulic brake device 80.

The above-described series of steps is included in the added braking control repeated in step S205. The CPU102 repeats the increase braking control until the target value QMG of the regenerative braking force of the second MG 72 reaches the target value of the braking force in the single pedal mode. When the target value QMG of the regenerative braking force of the second MG 72 reaches the target value of the braking force in the single pedal mode, the CPU102 ends the braking force increase process.

The CPU102 executes the braking force increasing process on the condition that the accelerator operation amount ACCP has a value within the deceleration region CD of the accelerator map (single pedal map) in fig. 2. In the case where the accelerator operation amount ACCP has a value outside the deceleration region CD of the single pedal map at the time point when the braking force increase process is started, the CPU102 does not perform the braking force increase process. In the case where the accelerator operation amount ACCP deviates from the deceleration region CD of the single pedal map during execution of the braking force increase process, the CPU102 ends the braking force increase process at the point of time of the deviation.

In the braking force increasing process of step S205, the hydraulic brake device 80 irregularly provides a partial braking force in the single pedal mode, and the CPU102 basically controls the vehicle 500 in the single pedal mode. Therefore, during execution of the braking force increasing process, the CPU102 causes the display 99 to display a message indicating that the current running mode is the single-pedal mode. When the braking force increasing process of step S205 is ended, the CPU102 advances the process to step S210. Then, the CPU102 executes the process of step S210 that has been described.

Details of the transition processing in step S170 will now be described.

In the transition process, the CPU102 repeats the following transition braking control. As shown in fig. 4, in the transition brake control, the CPU102 first executes the process of step S510. In step S510, the CPU102 calculates the first braking force a1 in the same manner as in step S130. Subsequently, the CPU102 advances the process to step S520.

In step S520, the CPU102 calculates the second braking force a2 in the same manner as in step S140. Subsequently, the CPU102 advances the process to step S530.

In step S530, the CPU102 calculates a provisional target value QMGx of the regenerative braking force of the second MG 72. More specifically, the CPU102 defines a provisional target value QMGx of the regenerative braking force of the second MG 72 such that the regenerative braking force set for the second MG 72 increases at a constant speed. That is, the CPU102 sets the provisional target value QMGx to a value obtained by adding a predetermined given additional value to the target value of the regenerative braking force set for the second MG 72 during the previous execution of the transition braking control. The given additional value is defined as the maximum value of the amount of increase in the regenerative braking force allowed in the second MG 72 during the execution period of the transition braking control by, for example, experiments. In the case where the transition brake control is executed for the first time after the transition process is started, the CPU102 regards the target value of the regenerative braking force that was last set for the second MG 72 when the vehicle 500 was controlled in the normal mode before the current transition process was started as the previous target value. After calculating the provisional target value QMGx, the CPU102 advances the process to step S540.

In step S540, the CPU102 calculates a target value QMG of the regenerative braking force of the second MG 72. More specifically, the CPU102 sets the target value QMG of the regenerative braking force of the second MG 72 to the smaller one of the provisional target value QMGx calculated in step S530 and the second braking force a2 calculated in step S520. When the provisional target value QMGx is equal to the second braking force a2, the CPU102 sets the target value QMG of the regenerative braking force of the second MG 72 to a value indicating the provisional target value QMGx and the second braking force a 2. Subsequently, the CPU102 advances the process to step S550.

In step S550, the CPU102 calculates a target value QHY of the braking force of the hydraulic brake device 80. More specifically, the CPU102 sets the target value QHY of the braking force of the hydraulic brake device 80 to a value obtained by subtracting the target value QMG of the regenerative braking force of the second MG 72 calculated in step S540 from the first braking force a1 calculated in step S510. Subsequently, the CPU102 advances the process to step S560.

In step S560, the CPU102 controls the second MG 72 using the target value QMG of the regenerative braking force of the second MG 72 calculated in step S540. Further, the CPU102 controls the hydraulic brake device 80 using the target value QHY of the braking force of the hydraulic brake device 80 calculated in step S550. Therefore, the CPU102 executes the process of step S510 again. The above-described processing of step S510 to step S560 is included in the transition braking control. The process of repeating the transition braking control is the transition process of step S170.

The operation of the present embodiment will now be described.

As shown in part (b) of fig. 5, at a time point T1 when the vehicle 500 is running in the normal mode, it is assumed that the occupant starts depressing the brake pedal 95. At a time point T2 in the middle of an increase in the brake operation amount BKP due to depression of the brake pedal 95, it is assumed that the occupant operates the mode selection switch 97. In this case, the CPU102 recognizes that the operation of the mode selection switch 97 by the occupant causes the issuance of a request for activating the single-pedal mode, and therefore the CPU102 starts the single-pedal process (step S100: YES). Even after the single pedal process is started, the CPU102 continues to execute control in the normal mode until the first braking force A1 becomes greater than or equal to the second braking force A2 (step S150: NO). That is, as shown in part (a) of fig. 5, the CPU102 controls the braking force of the vehicle 500 to become the first braking force a1 based on the brake operation amount BKP. In this control, the CPU102 distributes the first braking force a1 to the target value QMG of the regenerative braking force of the second MG 72 and the target value QHY of the braking force of the hydraulic brake device 80 at a predetermined distribution ratio. In part (a) of fig. 5, the target value QHY of the braking force of the hydraulic brake device 80 is displayed in a dot-shaped region.

Subsequently (i.e., after the time point T2), as shown in part (b) of fig. 5, it is assumed that the occupant continues to depress the brake pedal 95 to further increase the brake operation amount BKP. Therefore, as shown in part (a) of fig. 5, the first braking force a1 also increases. At a time point T3 after the time point T2, the first braking force A1 reaches the second braking force A2 (step S150: YES).

In the example shown in fig. 5, during a certain period after the time point T3, it is assumed that the second braking force a2 is kept almost constant (see part (a) of fig. 5). During a certain period after the time point T3, it is assumed that the brake operation amount BKP is greater than or equal to the value obtained at the time point T3 (see part (b) of fig. 5). In view of the balance, the first braking force a1 calculated using the brake operation amount BKP remains greater than or equal to the second braking force a2 during a certain period after the time point T3.

At a time point T3 when the first braking force a1 becomes the second braking force a2, the CPU102 activates the single pedal mode (step S160). Further, the CPU102 starts the transition process from the time point T3 (step S170). As described above, in the transition process, the CPU102 sets the target value QMG of the regenerative braking force of the second MG 72 to the smaller one of the second braking force a2 and the provisional target value QMGx obtained by adding the given additional value to the previous target value of the regenerative braking force of the second MG 72 (step S530). Therefore, the CPU102 selects the temporary target value QMGx as the target value QMG of the regenerative braking force of the second MG 72 until the temporary target value QMGx reaches the second braking force a 2. Therefore, as shown in part (a) of fig. 5, the target value QMG of the regenerative braking force of the second MG 72 increases at a constant speed after the time point T3 (T3 to T4). At a time point T4, the target value QMG of the regenerative braking force of the second MG 72 becomes the second braking force a 2. After the time point T4, the CPU102 sets the target value QMG of the regenerative braking force of the second MG 72 to the second braking force a 2. During execution of the transition process, the CPU102 assigns the difference between the first braking force a1 and the target value QMG of the regenerative braking force of the second MG 72 to the target value QHY of the braking force of the hydraulic brake device 80 (step S550).

As shown in part (b) of fig. 5, at a time point T5 when the first braking force a1 remains greater than or equal to the second braking force a2, it is assumed that the occupant releases the brake pedal 95. Therefore, as shown in part (a) of fig. 5, the first braking force a1 decreases after time point T5. At a time point T6 after the time point T5, the first braking force A1 falls below the second braking force A2 (step S180: YES). As a result, the CPU102 starts the single pedal mode (step S210).

When the single pedal mode is started, the CPU102 provides the braking force of the vehicle 500 using only the regenerative braking force of the second MG 72. As shown after part (c) of fig. 5, when the occupant operates the accelerator pedal 94 at a time point T7 after the time point T6 (more specifically, when the occupant increases the accelerator operation amount ACCP), the regenerative braking force of the second MG 72 decreases according to the relationship of the single pedal map as shown in fig. 2. Although not shown in the drawings, further increase in the accelerator operation amount ACCP generates driving force in the vehicle 500.

The example of fig. 5 shows a case where the target value QMG of the regenerative braking force of the second MG 72 reaches the second braking force a2 during the period (T3 to T6) in which the first braking force a1 remains greater than or equal to the second braking force a2(T4, step S200: yes). However, after the time point T3, when the occupant quickly releases the brake pedal 95, the first braking force A1 may fall below the second braking force A2 (step S200: NO). In this case, the CPU102 executes the braking force increasing process of step S205 to increase the target value QMG of the regenerative braking force of the second MG 72 to the target value of the braking force in the single pedal mode, thereby providing the braking force in the single pedal mode using only the regenerative braking force of the second MG 72 (step S210).

The advantages of the present embodiment will now be described.

(1) In the above-described embodiment, the single-pedal mode is activated (step S160) as long as the first braking force A1 is greater than or equal to the second braking force A2 when the brake pedal 95 is depressed (step S150: YES). This restricts a situation in which the running mode of the vehicle 500 remains unable to be changed from the normal mode to the single-pedal mode after the occupant operates the mode selection switch 97. Further, since the single pedal mode is activated in the case where the first braking force a1 is greater than or equal to the second braking force a2, the following advantages are obtained. That is, for example, the braking force of the vehicle 500 is prevented from being abruptly increased at the moment when the single pedal mode is activated.

(2) In the above-described embodiment, the braking force of the vehicle 500 is controlled to the first braking force a1 based on the brake operation amount BKP until the first braking force a1 falls below the second braking force a2 (T6 in fig. 5, S180: no) after the single-pedal mode is activated (T3 in fig. 5, step S160). Therefore, regardless of whether the occupant continues to operate the brake pedal 95, when the single pedal mode is activated (T3), the braking force of the vehicle 500 is not rapidly changed from the first braking force a1 to the second braking force a 2. Therefore, the braking force of the vehicle 500 can be prevented from suddenly increasing regardless of the operation performed by the occupant.

(3) The magnitude of the regenerative braking force that can be generated by the second MG 72 depends on the vehicle speed SP. In contrast, the braking force of the hydraulic brake device 80 is independent of the running state of the vehicle 500, such as the vehicle speed SP. In the above configuration, during execution of the transition process (S170), the difference between the target value (QMG) of the regenerative braking force of the second MG 72 and the first braking force a1 is distributed to the hydraulic brake device 80 (S550). In this way, a part of the braking force of the vehicle 500 is provided by the hydraulic brake device 80. Therefore, the braking force required to achieve the first braking force a1 is provided regardless of the running state of the vehicle 500.

(4) In the above configuration, in the case where the vehicle 500 is controlled in the single-pedal mode, only the second MG 72 is used to provide the braking force of the vehicle 500. Therefore, at the time point (T6, S210) when the single pedal mode is started, it is preferable that the second MG 72 be able to generate the second braking force a 2.

In the above-described configuration, in the case where the first braking force a1 is greater than or equal to the second braking force a2 for a sufficiently long period after the single-pedal mode is activated (T3, S160), the target value QMG of the regenerative braking force of the second MG 72 may be increased to the second braking force a2 through the transition process (S170) (T4, S200: yes). During the period (T4 to T6) that starts until the single pedal mode after the target value QMG is increased to the second braking force a2, the target value QMG of the regenerative braking force of the second MG 72 is maintained at the second braking force a 2. Therefore, when the first braking force A1 falls below the second braking force A2 (T6, S180: YES), the single pedal mode may be immediately started.

Even in the case where the first braking force a1 is greater than or equal to the second braking force a2 for a sufficiently short period of time after the single pedal mode is activated (T3, S160) (S200: no), the target value QMG of the regenerative braking force of the second MG 72 is increased to the second braking force a2 by the braking force increasing process (S205). Therefore, it is no problem that the braking force of the vehicle 500 is provided only by the second MG 72 in the single pedal mode.

The present embodiment may be modified as follows. The present embodiment and the following modifications may be combined as long as they are technically consistent with each other.

The contents of the single pedal process of changing the running mode of the vehicle from the normal mode to the single pedal mode are not limited to the examples of the above-described embodiments. The single pedal process only needs to include the content of activating the single pedal mode (step S160) when the first braking force a1 is greater than or equal to the second braking force a2 (step S150: yes). Further, the single pedal process only needs to include the content of starting the single pedal mode (step S210) after activating the single pedal mode (step S160). For example, the control in the normal mode may be canceled immediately after the start of the single-pedal process. The process of controlling the braking force of the vehicle 500 may be performed in a manner of distributing the braking force different from the manner of distributing the braking force in the conventional mode during the period after the start of the single-pedal process until the first braking force a1 becomes greater than or equal to the second braking force a2 (step S150: yes), that is, during the period after the start of the single-pedal mode until the single-pedal mode (T3 in fig. 5, step S160) is activated. More specifically, it is only necessary to activate the pre-activation transition process to control the braking force of the vehicle 500 using the first braking force a1 until the single-pedal mode is activated (T3 in fig. 5, step S160). The second MG 72 provides, for example, all the braking forces of the first braking force a1 that can be provided by the second MG 72, in such a manner that the first braking force a1 is distributed in this process. The braking force that cannot be completely provided by the second MG 72 may be provided by the hydraulic brake device 80.

Regarding the manner in which the first braking force a1 is distributed in the single pedal process including the transition process and the pre-activation transition process in the above-described modification, the first braking force a1 may be provided by the second MG 72 and the hydraulic brake device 80 using, for example, a preset distribution ratio.

Regarding the manner in which the first braking force a1 is distributed in the single pedal process, for example, the first braking force a1 may be provided entirely by the hydraulic brake device 80.

The vehicle 500 may use engine braking, i.e., may consume the running energy of the vehicle 500 by increasing the pumping loss of the internal combustion engine 70. Regarding the manner in which the first braking force A1 is distributed in the single pedal process, for example, at least a portion of the first braking force A1 may be provided by engine braking.

Regarding the manner in which the first braking force a1 is distributed in the single pedal process, for example, the first braking force a1 may be achieved without using the hydraulic brake device 80. In this case, for example, the second MG 72 provides all the braking force of the first braking force a1 that can be provided by the second MG 72. The braking force that cannot be provided entirely by the second MG 72 may be provided by engine braking.

As for the manner of distributing the first braking force a1 in the single-pedal process, for example, a plurality of manners of distributing the first braking force a1 may be set in advance such that when the single-pedal process is started, an appropriate distribution manner is selected according to, for example, the running state of the vehicle 500.

The point in time when the single pedal mode is activated is not limited to the example of the above-described embodiment. The point in time when the single pedal mode is activated only needs to be after the point in time when the first braking force a1 reaches the second braking force a 2.

The point in time when the single pedal mode is started is not limited to the example of the above-described embodiment. The single pedal mode may be initiated before a point in time when the first braking force a1 falls below the second braking force a2 after the single pedal mode is activated. For example, the single-pedal mode may be started at a point of time when the single-pedal mode is activated. This prevents the braking force of the vehicle 500 from suddenly increasing.

In the case where the single pedal mode is started at a time point such as in the modification of the previous paragraph, the transition process is omitted. That is, it is not necessary to perform control so that the braking force of the vehicle 500 becomes the first braking force a1 using the transition process until the first braking force a1 falls below the second braking force a 2.

The content of the message displayed on the display 99 and the time point of the message displayed on the display 99 may be changed according to, for example, the time point of activating the single pedal mode.

The braking force (second braking force a2) defined in the calculation map in the single pedal mode when the accelerator operation amount ACCP is zero is not limited to the example of the above-described embodiment. The braking force in the single-pedal mode with the accelerator operation amount ACCP being zero is not necessarily the maximum value of the regenerative braking force permitted in the second MG 72 at each vehicle speed SP. For example, the braking force in the single pedal mode with the accelerator operation amount ACCP being zero may be set to a value larger than the maximum value of the regenerative braking force allowed in the second MG 72. In this case, the braking force obtained when the vehicle 500 is controlled in the single-pedal mode may be provided by, for example, the second MG 72 and the hydraulic brake device 80. The regenerative braking force permitted in the second MG 72 may be sufficiently large depending on the specifications of the second MG 72 and its peripheral components. In this case, the braking force in the single pedal mode with the accelerator operation amount ACCP being zero may be set to a value smaller than the maximum value of the regenerative braking force allowed in the second MG 72.

The braking force in the single pedal mode with the accelerator operation amount ACCP of zero can be set without taking into account the regenerative braking force permitted in the second MG 72. As long as the braking force obtained when the vehicle 500 is controlled in the single pedal mode is not provided by only the second MG 72, the regenerative braking force allowed in the second MG 72 does not have to be reflected on the braking force in the single pedal mode obtained when the accelerator operation amount ACCP is zero.

The contents of the single pedal map are not limited to the examples of the above-described embodiments. For example, the accelerator operation amount ACCP in which the driving force and the braking force are zero may be set to a sufficiently wide range of the accelerator operation amount ACCP, instead of the specific value (i.e., the neutral point CV).

The manner of distributing the braking force obtained when controlling the vehicle 500 in the single-pedal mode is not limited to the example of the above-described embodiment. For example, the braking force may be provided by the second MG 72 and the hydraulic brake device 80. Alternatively, the braking force may be provided only by the hydraulic brake device 80. Alternatively, at least a portion of the braking force may be provided by engine braking. The manner in which the braking force is distributed may be changed according to, for example, the traveling state of the vehicle 500.

The manner of distributing the braking force obtained when the vehicle 500 is controlled in the normal mode is not limited to the example of the above-described embodiment. For example, the braking force may be provided only by the hydraulic brake device 80 or the second MG 72. Alternatively, at least a portion of the braking force may be provided by engine braking. The manner in which the braking force is distributed may be changed according to, for example, the traveling state of the vehicle 500.

The manner in which the single pedal mode is activated is not limited to the examples of the above-described embodiments. Once given conditions of the driving state of the vehicle 500 are satisfied, the request to activate the single-pedal mode may be deemed to have been issued. For example, the given condition is that the number of times of performing switching between the accelerator pedal 94 and the brake pedal 95 becomes a given number of times or more. Alternatively, for example, the given condition is that a downhill road continues for a given length or longer.

The pedal used in the single pedal mode (second mode pedal) may be the brake pedal 95. In this case, the contents of the single pedal map need only be changed so that the single pedal mode is provided by brake pedal 95.

The configuration of the vehicle 500 is not limited to the example of the above-described embodiment. For example, the vehicle 500 may have a configuration in which the first MG 71 and the second MG 72 are not provided and only the internal combustion engine 70 is used as a drive source. Additionally, the vehicle 500 may be a battery electric vehicle that does not include the internal combustion engine 70. The manner in which the braking force is distributed need only be defined according to the configuration of the vehicle 500.

When a request to activate the single-pedal mode is received from the occupant in the case where the vehicle 500 is controlled in the normal mode and in the case where the accelerator operation amount ACCP is greater than zero, the single-pedal mode does not have to be activated immediately and may be activated when a predetermined condition is satisfied. More specifically, the CPU102 executes a first driving force calculation process of calculating a first driving force with a first driving force of the target value of the driving force in the normal mode using the accelerator operation amount ACCP. In this process, the CPU102 calculates a target value of the driving force corresponding to the latest accelerator operation amount ACCP as the first driving force using a normal driving force map. Further, the CPU102 executes a second driving force calculation process of calculating a second driving force having a target value of the driving force for the case where the driving force of the vehicle 500 is controlled in the single-pedal mode, using the accelerator operation amount ACCP. In this process, the CPU102 calculates a target value of the driving force corresponding to the latest accelerator operation amount ACCP as the second driving force using the single pedal map. When the first driving force is greater than or equal to the second driving force, the CPU102 executes an activation process that activates the single-pedal mode. The processing content of the CPU102 may be made so as to realize such a mode.

In this configuration, the single-pedal mode is activated as long as the condition that the first driving force is greater than or equal to the second driving force is satisfied. This restricts, for example, a situation in which the running state of the vehicle 500 different from the running state of the vehicle 500 desired by the occupant continues. Further, in this configuration, when the second driving force is larger than the first driving force, the single-pedal mode is not activated. This prevents the vehicle 500 from being suddenly accelerated, for example, at the moment the single pedal mode is activated.

Various changes in form and detail may be made to the above-described examples without departing from the spirit and scope of the claims and their equivalents. The examples are for purposes of illustration only and are not intended to be limiting. The description of features in each example will be considered to apply to similar features or aspects in other examples. Suitable results may be achieved if the order is performed in a different order and/or if components in a described system, architecture, device, or circuit are combined in a different manner and/or replaced or supplemented by other components or their equivalents. It is intended that the scope of the disclosure be limited not by this detailed description, but rather by the claims appended hereto and their equivalents. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their disclosure.

Claims

1. A vehicle controller configured to control travel of the vehicle using a first mode and a second mode, wherein,

the first mode controls the driving force of the vehicle using the operation amount of an accelerator pedal, and controls the braking force of the vehicle using the operation amount of a brake pedal,

the second mode controls the driving force and the braking force of the vehicle using one of the operation amount of the accelerator pedal and the operation amount of the brake pedal,

the vehicle controller is configured to execute a first braking force calculation process, a second braking force calculation process, and an activation process when a request to activate the second mode is received in a situation where an operation amount of the brake pedal is greater than zero during control of the vehicle in the first mode,

the first braking force calculation process calculates a first braking force that is a target value of the braking force in the first mode using the operation amount of the brake pedal,

the second braking force calculation process calculates a second braking force that is a target value of braking force for a case where the braking force of the vehicle is controlled in a second mode using an operation amount of a second mode pedal for the second mode, and

the activation process activates the second mode when the first braking force is greater than or equal to the second braking force.

2. The vehicle controller according to claim 1,

the second mode pedal is the accelerator pedal,

the vehicle controller is configured to execute a transition process when a request to activate the second mode is received in a situation where an operation amount of the brake pedal is greater than zero during control of the vehicle in the first mode, and

the transition process controls the braking force of the vehicle to the first braking force until the first braking force falls below the second braking force regardless of whether the second mode is activated.

3. The vehicle controller according to claim 2,

the vehicle includes:

a hydraulic brake device that generates braking force using hydraulic pressure; and

a generator that generates a regenerative braking force corresponding to the amount of power generation,

the vehicle controller is configured to control the vehicle such that at least the hydraulic braking device is used to provide the first braking force that is obtained when the vehicle is controlled in the first mode,

the vehicle controller is configured to control the vehicle such that only the generator is used to provide the second braking force obtained when the vehicle is controlled in the second mode, and

the vehicle controller is configured to, in the transition process, control the vehicle such that the hydraulic brake device is used to provide at least a part of the first braking force even when the second mode is activated.

4. The vehicle controller according to claim 2,

the vehicle includes:

in the transition process, the vehicle controller is configured to control the vehicle such that the generator generates the braking force of the maximum value even if the second mode is activated when the first braking force is greater than the maximum value of the regenerative braking force allowed in the generator at a running speed of the vehicle, and the hydraulic braking device compensates for a difference between the first braking force and the maximum value.

5. A vehicle control program that causes a processor to execute a control process to control travel of a vehicle using a first mode and a second mode, the control process including:

controlling a driving force of the vehicle using an operation amount of an accelerator pedal and controlling a braking force of the vehicle using an operation amount of a brake pedal in the first mode;

controlling a driving force and a braking force of the vehicle using one of an operation amount of the accelerator pedal and an operation amount of the brake pedal in the second mode; and

executing a first braking force calculation process, a second braking force calculation process, and an activation process when a request to activate the second mode is received in a situation where an operation amount of the brake pedal is greater than zero during control of the vehicle in the first mode, wherein,

the second braking force calculation process calculates a second braking force that is a target value of a braking force for a case where the braking force of the vehicle is controlled in a second mode using an operation amount of a second mode pedal for the second mode, and

6. A storage medium storing a program according to claim 5 to cause the processor to execute the control processing.

7. A vehicle controller configured to control travel of a vehicle using a first mode and a second mode, wherein,

the vehicle controller is configured to execute a first driving force calculation process, a second driving force calculation process, and an activation process when a request to activate the second mode is received in a situation where an operation amount of the accelerator pedal is greater than zero during control of the vehicle in the first mode,

the first driving force calculation process calculates a first driving force that is a target value of the driving force in the first mode using an operation amount of the accelerator pedal,

the second driving force calculation process calculates a second driving force that is a target value of the driving force for a case where the driving force of the vehicle is controlled in the second mode, using an operation amount of a second mode pedal for the second mode, and

the activation process activates the second mode when the first driving force is greater than or equal to the second driving force.

8. A vehicle control method for controlling travel of a vehicle using a first mode and a second mode, the vehicle control method comprising: