CN114347992B

CN114347992B - Vehicle controller, storage medium, and vehicle control method

Info

Publication number: CN114347992B
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: 2023-09-19
Anticipated expiration: 2041-09-18
Also published as: JP2022054702A; CN114347992A; DE102021122851A1; JP7331814B2

Abstract

A vehicle controller, a storage device, and a vehicle control method are provided. The second mode controls the driving force and 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. When the first braking force is greater than or equal to the second braking force, the activation process activates the second mode.

Description

Vehicle controller, storage medium, and vehicle control method

Technical Field

The present disclosure relates to a vehicle controller, 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 the running of the vehicle by switching between two running 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 that controls the driving force and braking force of the vehicle using the operation amount of the accelerator pedal.

Even in the case where a request to switch from the normal mode to the single pedal mode is received, if the occupant presses the pedal at the point of time when the switch request is issued, 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 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 after the occupant switches to the accelerator pedal until the operation amount of the accelerator pedal reaches a given amount. Therefore, the amount of deceleration of the vehicle during this period may be greatly 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 greater than a given amount, the operation amount of the accelerator pedal remains unreflected on the driving force of the vehicle. Therefore, in the same manner as the deceleration amount of the vehicle, the acceleration amount of the vehicle continues to be different from the acceleration amount intended by the occupant.

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 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 case where an operation amount of a brake pedal during control of the vehicle in the first mode is greater than zero. The first braking force calculation process calculates a first braking force, which is a target value of 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, which is a target value of 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 used in the second mode. When the first braking force is greater than or equal to the second braking force, the activation process activates the second mode.

In this configuration, the second mode is activated as long as a condition that the first braking force is greater than or equal to the second braking force is satisfied. This limits, for example, a situation in which the running state of the vehicle is continued, which is different from the running state of the vehicle desired by the occupant. 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 braked suddenly, for example at the moment 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 a transition process when a request to activate the second mode is received in a case where an operation amount of the 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 quickly 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. Thus, without the occupant performing an operation, the braking force of the vehicle is prevented from suddenly increasing.

Aspect 3: the vehicle equipped with the vehicle controller according to aspect 2 includes: a hydraulic brake device that generates a braking force using a hydraulic pressure; and a generator that generates a regenerative braking force corresponding to the power generation amount. 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 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 a second braking force 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 portion of the first braking force even when the second mode is activated in the transition process.

In this configuration, during the transition process, at least a portion of the braking force of the vehicle is provided by the hydraulic pressure, regardless of whether the second mode is activated. 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 a braking force using a hydraulic pressure; and a generator that generates a regenerative braking force corresponding to the power generation amount. 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 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 a second braking force 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 a 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 end of the transition process. When the generator is not capable of providing the first braking force, 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 running 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 in a first mode, and controlling a braking force of the vehicle using an operation amount of a brake pedal; controlling driving force and braking force of the vehicle using one of an operation amount of an accelerator pedal and an operation amount of a brake pedal in a second mode; and when a request to activate the second mode is received in a case where an operation amount of the brake pedal is greater than zero during control of the vehicle in the first mode, performing a first braking force calculation process, a second braking force calculation process, and an activation process. 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, which is a target value of 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 used in the second mode. When the first braking force is greater than or equal to the second braking force, the activation process activates the second mode.

Aspect 6: a storage medium storing the program according to aspect 5 is provided to cause a processor to execute control processing. 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 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 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 case where an operation amount of an accelerator pedal during control of the vehicle in the first mode is greater than zero. 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 the second mode pedal, which is used in the second mode. The second driving force is a target value of driving force for a 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 limits, for example, a situation in which the running state of the vehicle is continued, which is different from the running state of the vehicle desired by the occupant. In this configuration, when the second driving force is greater 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 may be provided that causes a processor to execute various processes described in aspect 7. Further, a storage medium storing a program that causes a processor to execute the various processes described in aspect 7 may be provided.

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

Drawings

Fig. 1 is a schematic diagram showing a 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 running mode of the vehicle from the normal mode to the single pedal mode.

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

Fig. 5 is a time chart including portions (a) to (c), showing an example of temporal variation of a variable in the single pedal process.

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

Detailed Description

The description provides a thorough understanding of the described methods, apparatus and/or systems. Modifications and equivalents of the described methods, apparatus and/or systems will be apparent to those skilled in the art. The order of the operations is exemplary, except for operations that must occur in a particular order, and the order of the operations may be altered in ways that will be apparent to those of 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. However, the examples described 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 driving 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 the 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 planet carrier 44 is coupled to the crankshaft 34, which crankshaft 34 is the 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. Differential 61 allows a rotational speed difference to occur between left and right driven wheels 62.

The internal combustion engine 70 and the first MG 71 can transmit 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 an electric motor, the crankshaft 34 may 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, a 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 an electric 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 according to 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 presses against the rotor that rotates integrally with the driven wheel 62. This causes the braking 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.

Vehicle 500 includes an accelerator pedal 94 and a brake pedal 95. The accelerator pedal 94 and the brake pedal 95 are foot pedals 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 the 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. A mode selection 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, each time the mode selection switch 97 is pressed, the running mode is switched from one to the other of the normal mode and the single pedal mode.

The vehicle 500 includes a display 99. A display 99 is located in the passenger compartment. The display 99 can display various types of information. For example, the display 99 uses icons and messages to indicate whether the travel mode of the vehicle 500 is a regular mode or a 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 one or more dedicated hardware circuits including at least a portion performing various processes, such as an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), or a circuit including a combination thereof. The processor includes a CPU 102 and memory, such as RAM and ROM 104. The memory stores program codes (vehicle control programs) or instructions configured to cause the CPU 102 to execute a process (control process). The memory or computer-readable medium includes any type of medium or non-transitory computer-readable storage medium accessible by a general-purpose computer and a special-purpose computer.

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

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

the 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 CPU 102 uses the detection results of the various sensors to control the running of the vehicle 500. The CPU 102 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 that controls the driving force and braking force of the vehicle 500 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 that is used in the second mode. In the present embodiment, the CPU 102 controls the vehicle 500 such that the hydraulic brake device 80 and the second MG 72 provide braking forces for controlling the vehicle 500 in the normal mode. The CPU 102 controls the vehicle 500 such that only the second MG 72 provides braking force for controlling the vehicle 500 in the single pedal mode.

In the normal mode, the CPU 102 controls the driving force of the vehicle 500 using the normal driving 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 driving force increases. In order to control the driving force of the vehicle 500, the CPU 102 refers to the latest accelerator operation amount ACCP and the regular drive map to calculate a target value of the driving force corresponding to the accelerator operation amount ACCP in the regular drive map. The CPU 102 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 CPU 102 basically controls the first MG 71 and the second MG 72 by controlling the inverter.

In the normal mode, the CPU 102 controls the braking force of the vehicle 500 using the normal braking map stored in the ROM 104. The conventional brake map shows a 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. In order to control the braking force of the vehicle 500, the CPU 102 refers to the latest brake operation amount BKP and the regular brake map to calculate a target value of the braking force corresponding to the brake operation amount BKP in the regular brake map. The CPU 102 allocates the calculated target value to the hydraulic brake device 80 and the second MG 72 in a predetermined allocation manner. In the present embodiment, the CPU 102 allocates approximately two thirds of the target value of the braking force calculated by the conventional braking map to the hydraulic brake device 80, and allocates approximately one third of the target value to the second MG 72. The CPU 102 sets the amount of braking force allocated to the hydraulic brake device 80 as a target value QHY of the braking force of the hydraulic brake device 80, and uses the target value QHY to control the hydraulic pressure of the hydraulic brake device 80. Further, the CPU 102 sets the amount of braking force allocated to the second MG 72 as a target value QMG of regenerative braking force of the second MG 72, and uses the target value QMG to control the torque of the second MG 72.

In the single pedal mode, the CPU 102 controls the driving force and braking force of the vehicle 500 using the 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 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.

In order to control the vehicle 500 in the single pedal mode, the cpu 102 refers to the latest accelerator operation amount ACCP and the single pedal map corresponding to the latest vehicle speed SP. The CPU 102 calculates a target value of braking force or a target value of 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 CPU 102 calculates a target value of the driving force corresponding to the accelerator operation amount ACCP. The CPU 102 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 CPU 102 calculates a target value of braking force corresponding to the accelerator operation amount ACCP. The CPU 102 controls the torque of the second MG 72 so that the braking force of the vehicle 500 has a target value.

The CPU 102 can execute mode change processing. That is, when the CPU 102 receives the change request signal G in the case where the running mode of the vehicle 500 is the normal mode, a process of changing the running mode to the one-pedal mode is performed as the mode changing process. When the CPU 102 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 performed as the mode changing process. The CPU 102 basically processes the change request signal G as a signal to activate the single pedal mode or the normal mode. For example, in this activation, activating the single pedal mode refers to completing preparation for control performed by the CPU 102 in the single pedal mode.

In the mode changing 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 CPU 102 executes each step of the single pedal process by executing a program stored in the ROM 104. When the CPU 102 controls the vehicle 500 in the normal mode before starting the single pedal process, the CPU 102 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 CPU 102 receives the change request signal G in the 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 CPU 102 executes the process of step S100. In step S100, the CPU 102 determines whether the brake operation amount BKP is greater than zero. The CPU 102 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 CPU 102 advances the process to step S400.

In step S400, the CPU 102 determines whether the accelerator operation amount ACCP is greater than zero. The CPU 102 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 CPU 102 advances the process to step S410.

In step S410, the CPU 102 causes the display 99 to display a message indicating that the running mode of the vehicle 500 cannot be changed to the single pedal mode. In order to change the running mode to the single pedal mode, the CPU 102 causes the display 99 to display a message indicating that the mode selection switch 97 needs to be operated in the case where the accelerator pedal 94 or the brake pedal 95 is depressed. Subsequently, the CPU 102 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 CPU 102 advances the process to step S210. When the determination of step S400 is yes, the CPU 102 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 accelerator operation amount ACCP is greater than zero.

In step S210, the CPU 102 starts control in the single pedal mode after activating the single pedal mode. Further, the CPU 102 causes the display 99 to display a message indicating that the current running mode of the vehicle 500 is the single pedal mode. Subsequently, the CPU 102 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 CPU 102 advances the process to step S110. When the determination of step S100 is yes, the CPU 102 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 CPU 102 continues to control the vehicle 500 in the normal mode until the process of step S170 (described later) is performed.

In step S110, the CPU 102 determines whether the accelerator operation amount ACCP is zero. When the determination of the above step S100 is yes, the accelerator operation amount ACCP is likely to be zero, but is not always zero. The determination of step S110 is a process of checking whether the accelerator operation amount ACCP is zero. The CPU 102 executes the processing 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 CPU 102 advances the process to step S410, which has been described above. When the accelerator operation amount ACCP is zero (yes in step S110), the CPU 102 advances the process to step S120.

In step S120, the CPU 102 causes the display 99 to display a message indicating that the process of starting the single pedal mode is being performed. Further, the CPU 102 causes the display 99 to display a message prompting continued depression of the brake pedal 95. After executing the process of step S120, the CPU 102 advances the process to step S130.

In step S130, the CPU 102 calculates a first braking force A1. The first braking force A1 is a target value of the braking force in the normal mode. The CPU 102 refers to the latest brake operation amount BKP and the conventional brake map stored in the ROM 104. The CPU 102 calculates a target value of braking force corresponding to the latest brake operation amount BKP in the normal brake map as the first braking force A1. After calculating the first braking force A1, the CPU 102 advances the process to step S140. The process of step S130 is a first braking force calculation process.

In step S140, the CPU 102 calculates a second braking force A2. More specifically, the CPU 102 calculates a target value of the braking force for the case where the current braking force of the vehicle 500 is controlled using the single pedal mode as the second braking force A2. In detail, the CPU 102 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 allowed in the second MG 72 in each vehicle speed SP.

In order to calculate the second braking force A2, the CPU 102 refers to the latest vehicle speed SP. The CPU 102 refers to the calculation map stored in the ROM 104. The CPU 102 calculates a regenerative braking force corresponding to the latest vehicle speed SP in the calculation map as the second braking force A2. After calculating the second braking force A2, the CPU 102 advances the process to step S150. The process of step S140 is a second braking force calculation process.

In step S150, the CPU 102 determines whether the first braking force A1 is greater than or equal to the second braking force A2. More specifically, the CPU 102 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 CPU 102 advances the process to step S300.

In step S300, the CPU 102 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 operation 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 a time from the start of depressing the brake pedal 95 when the brake pedal 95 is operated at the depression speed, the first braking force A1 becomes the maximum braking force according to the depression of the brake pedal 95.

When the elapsed time from the start of the one-pedal process is smaller than the given period H (step S300: no), the CPU 102 returns to the process of S130. Then, the CPU 102 executes the processing of step S130, step S140, and step S150 again. When the determination of step S150 remains no, the CPU 102 repeats the processing of step S130, step S140, and step S150 until the elapsed time from the start of the one-pedal processing reaches a given period H. During the repetition of the processes at step S130 to step S150 and step S300, when the elapsed time becomes greater than or equal to the given period H and the determination at step S150 does not become yes (step S300: yes), the CPU 102 proceeds to the process at 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 start of the single pedal process.

In step S310, the CPU 102 causes the display 99 to display a message indicating that the running mode of the vehicle 500 cannot be changed to the single pedal mode. Further, the CPU 102 causes the display 99 to indicate that the running 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 time elapsed from the start of the one-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 CPU 102 advances the process to step S160. One of the cases in which step S150 becomes yes is a case in which the brake operation amount BKP is sufficiently large at the time point when the single pedal process is started. Another of the cases in which step S150 becomes yes is a case in which the brake operation amount BKP gradually increases to be sufficiently large after the start of the single pedal process.

In step S160, the CPU 102 activates the single pedal mode. That is, if the occupant releases the brake pedal 95 and starts depressing the accelerator pedal 94, the CPU 102 makes preparations so as to execute control of the driving force or braking force based on the accelerator operation amount ACCP. At the point of time when step S160 is performed, the brake pedal 95 is still depressed, and thus control of the driving force or braking force in the single pedal mode has not been performed. Further, in step S160, the CPU 102 causes the display 99 to display a message indicating that preparation for running in the single pedal mode has been made. Further, the CPU 102 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 CPU 102 advances the process to step S170. The process of step S160 is an activation process.

In step S170, the CPU 102 cancels the vehicle control in the normal mode and starts the transition processing. The shift 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 A2. The shift process also increases the target value QMG of the regenerative braking force of the second MG 72 toward the second braking force A2. In the transition processing, the CPU 102 repeatedly calculates 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 CPU 102 advances the processing to step S180.

In step S180, the CPU 102 determines whether the first braking force A1 is smaller than the second braking force A2. More specifically, the CPU 102 refers to the latest first braking force A1 and the latest second braking force A2 calculated in the transition processing. When the first braking force A1 is greater than or equal to the second braking force A2 (step S180: no), the CPU 102 executes the processing of step S180 again. The CPU 102 repeats the processing of step S180 until the first braking force A1 becomes smaller than the second braking force A2. When the first braking force A1 becomes smaller than the second braking force A2 (yes in step S180), the CPU 102 advances the process to step S190. When the decrease in the brake operation amount BKP decreases the first braking force A1 so that the first braking force A1 eventually falls below the second braking force A2, step S180 becomes yes.

In step S190, the CPU 102 ends the transition processing. Subsequently, the CPU 102 advances the process to step S200.

In step S200, the CPU 102 determines whether the target value QMG of the regenerative braking force of the second braking force A2 last calculated in the transition processing is equal to the value of the second braking force A2 last calculated in the transition processing. When the determination is yes (step S200: yes), the CPU 102 skips the processing of step S205 (described later) and advances the processing 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 by only the regenerative power of the second MG 72 from the point of time when the shift process ends.

In step S210, the CPU 102 starts control in the single pedal mode. Further, the CPU 102 causes the display 99 to display a message indicating that the current running mode is the single pedal mode. Subsequently, the CPU 102 ends a series of steps of the single pedal process (shift single 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 finally calculated in the transition process is smaller than the value of the second braking force A2 finally calculated in the transition process), the CPU 102 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 processing (S170 to S190), the determination of step S200 becomes no. When the execution period of the transition process is short (for example, when the passenger releases the brake pedal 95 immediately after the start of the transition process), 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 the regenerative power of the second MG 72 alone at the point of time when the transition process ends. Accordingly, the CPU 102 executes the processing of step S205.

In step S205, the CPU 102 executes braking force increasing processing. This process rapidly increases the proportion of the braking force in the single pedal mode 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 in the shift process, the hydraulic brake device 80 compensates for the difference between the target value of the braking force in the single pedal mode and the target value QMG of the regenerative braking force of the second MG 72.

More specifically, the CPU 102 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 that of the transition braking control of the transition processing in step S170 to be described later. In the increase braking control, the CPU 102 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 CPU 102 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 increase braking control. The given additional value will be described later in relation to the transition processing. In the case where the increase braking control is executed for the first time after the start of the braking force increase process, the CPU 102 regards the target value of the regenerative braking force that is finally set for the second MG 72 when the transition process is executed before the start of the current braking force increase process as the previous target value. The CPU 102 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 CPU 102 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 CPU 102 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 series of steps are included in the increasing brake control repeated in step S205. The CPU 102 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 CPU 102 ends the braking force increasing process.

The CPU 102 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 point of time when the braking force increasing process starts, the CPU 102 does not execute the braking force increasing 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 increasing process, the CPU 102 ends the braking force increasing process at the deviated point in time.

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 CPU 102 basically controls the vehicle 500 in the single pedal mode. Thus, during execution of the braking force increasing process, the CPU 102 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 CPU 102 advances the process to step S210. Then, the CPU 102 executes the processing of step S210 that has been described.

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

In the transition processing, the CPU 102 repeats the following transition brake control. As shown in fig. 4, in the transition brake control, the CPU 102 first executes the process of step S510. In step S510, the CPU 102 calculates the first braking force A1 in the same manner as in step S130. Subsequently, the CPU 102 advances the process to step S520.

In step S520, the CPU 102 calculates the second braking force A2 in the same manner as in step S140. Subsequently, the CPU 102 advances the process to step S530.

In step S530, the CPU 102 calculates a tentative target value QMGx of the regenerative braking force of the second MG 72. More specifically, the CPU 102 defines a tentative 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 CPU 102 sets the tentative 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 preceding execution of the transition braking control. The given additional value is defined by, for example, experiments 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 changeover braking control. In the case where the transition brake control is executed for the first time after the start of the transition process, the CPU 102 regards the target value of the regenerative braking force that is last set for the second MG 72 as the previous target value when the vehicle 500 is controlled in the normal mode before the start of the current transition process. After calculating the tentative target value QMGx, the CPU 102 advances the process to step S540.

In step S540, the CPU 102 calculates a target value QMG of the regenerative braking force of the second MG 72. More specifically, the CPU 102 sets the target value QMG of the regenerative braking force of the second MG 72 to the smaller one of the tentative 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 CPU 102 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 A2. Subsequently, the CPU 102 advances the process to step S550.

In step S550, the CPU 102 calculates a target value QHY of the braking force of the hydraulic brake device 80. More specifically, the CPU 102 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 CPU 102 advances the process to step S560.

In step S560, the CPU 102 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 CPU 102 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. Accordingly, the CPU 102 executes the processing of step S510 again. The above-described processing of steps S510 to S560 is included in the transition brake control. The process of repeating the transition brake 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 traveling in the normal mode, it is assumed that the occupant starts depressing the brake pedal 95. At a point in time 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 CPU 102 recognizes that the request for activating the single pedal mode is issued by the operation of the occupant mode selection switch 97, and therefore the CPU 102 starts the single pedal process (step S100: yes). Even after the start of the single pedal process, the CPU 102 continues to perform 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 CPU 102 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 CPU 102 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, a target value QHY of the braking force of the hydraulic brake device 80 is displayed in a dot-like 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 balance, the first braking force A1 calculated using the brake operation amount BKP is kept 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 CPU 102 activates the single pedal mode (step S160). Further, the CPU 102 starts the transition processing from the time point T3 (step S170). As described above, in the shift process, the CPU 102 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 tentative 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). Accordingly, the CPU 102 selects the tentative target value QMGx as the target value QMG of the regenerative braking force of the second MG 72 until the tentative target value QMGx reaches the second braking force A2. 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 the time point T4, the target value QMG of the regenerative braking force of the second MG 72 becomes the second braking force A2. After the time point T4, the CPU 102 sets the target value QMG of the regenerative braking force of the second MG 72 as the second braking force A2. During execution of the shift process, the CPU 102 assigns a 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 the 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 CPU 102 starts the single pedal mode (step S210).

When the single pedal mode is started, the CPU 102 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, a 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 drop below the second braking force A2 (step S200: no). In this case, the CPU 102 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 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 limits the situation in which the running mode of the vehicle 500 remains unchanged 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 advantage is obtained. That is, for example, the braking force of the vehicle 500 is prevented from suddenly increasing 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 after the single pedal mode (T3 in fig. 5, step S160) is activated (T6 in fig. 5, S180: no). 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 quickly changed from the first braking force A1 to the second braking force A2. 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 shift 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 allocated to the hydraulic brake device 80 (S550). In this way, a portion 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-described 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 point of time when the single pedal mode starts (T6, S210), the second MG 72 is preferably able to generate the second braking force A2.

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 (T3, S160) is activated, the target value QMG of the regenerative braking force of the second MG 72 may be increased to the second braking force A2 by the shift process (S170) (T4, S200: yes). The target value QMG of the regenerative braking force of the second MG 72 is maintained at the second braking force A2 during a period (T4 to T6) starting until the single pedal mode after the target value QMG is increased to the second braking force A2. Therefore, when the first braking force A1 falls below the second braking force A2 (T6, S180: yes), the single pedal mode can 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 (T3, S160) is activated (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 not problematic that the braking force of the vehicle 500 is provided only by the second MG 72 in the single pedal mode.

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

The content of the single pedal process of changing the running mode of the vehicle from the normal mode to the single pedal mode is not limited to the example of the above embodiment. The single pedal process need only 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 need only include the content of starting the single pedal mode (step S210) after the single pedal mode is activated (step S160). For example, after the start of the single pedal process, the control in the normal mode may be canceled immediately. The process of controlling the braking force of the vehicle 500 may be performed in a manner of distributing the braking force different from that in the conventional mode, during a period after the single pedal process is started until the first braking force A1 becomes greater than or equal to the second braking force A2 (step S150: yes), that is, during a period after the single pedal mode is started until the single pedal mode is activated (T3 in fig. 5, step S160). More specifically, only the pre-activation transition process needs to be activated 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). In such a manner that the first braking force A1 is distributed in this process, 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. 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 shift process and the pre-activation shift process in the above 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 driving 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.

As for the manner of distributing the first braking force A1 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 forces of the first braking force A1 that can be provided by the second MG 72. The braking force that cannot be completely provided 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 so 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 time point when the single pedal mode is activated is not limited to the example of the above embodiment. The time point when the single pedal mode is activated only needs to be after the time point when the first braking force A1 reaches the second braking force A2.

The time point when the single pedal mode is started is not limited to the example of the above embodiment. The single pedal mode may be started before a point in time at which 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 point of time such as in the modification of the previous paragraph, the transition process is omitted. That is, it is not necessary to perform control using the shift process so that the braking force of the vehicle 500 becomes the first braking force A1 until the first braking force A1 falls below the second braking force A2.

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 when the single pedal mode is activated.

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 embodiment. The braking force in the single pedal mode in the case where the accelerator operation amount ACCP is zero does not have to be the maximum value of the regenerative braking force allowed in the second MG 72 at each vehicle speed SP. For example, the braking force in the single pedal mode in the case where the accelerator operation amount ACCP is 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. Depending on the specifications of the second MG 72 and its peripheral components, the regenerative braking force allowed in the second MG 72 may be sufficiently large. 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 in the case where the accelerator operation amount ACCP is zero may be set regardless of the regenerative braking force allowed 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 the second MG 72 alone, the regenerative braking force allowed in the second MG 72 is not necessarily reflected on the braking force obtained in the single pedal mode when the accelerator operation amount ACCP is zero.

The content of the single pedal map is 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 the vehicle 500 is controlled in the single pedal mode is not limited to the example of the embodiment described above. 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 by the hydraulic brake device 80 alone. 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 running 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 embodiment described above. For example, the braking force may be provided by only 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 running state of the vehicle 500.

The manner of activating the single pedal mode is not limited to the examples of the above-described embodiments. Once a given condition of the running state of the vehicle 500 is satisfied, a request to activate the single pedal mode may be considered issued. For example, the given condition is that the number of times of executing the switch 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 the downhill path last for a given length or longer.

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

The configuration of the vehicle 500 is not limited to the examples of the above-described embodiments. 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 the 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 in accordance with 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, it is not necessary to activate the single pedal mode immediately and the single pedal mode may be activated when a predetermined condition is satisfied. More specifically, the CPU 102 performs a first driving force calculation process of calculating a first driving force having a target value of the driving force in the normal mode using the accelerator operation amount ACCP. In this process, the CPU 102 calculates a target value of the driving force corresponding to the latest accelerator operation amount ACCP as the first driving force using a conventional driving force map. Further, the CPU 102 executes a second driving force calculation process of calculating a second driving force having a target value of driving force for a 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 CPU 102 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 CPU 102 executes activation processing to activate the single pedal mode. The processing contents of the CPU 102 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, which is 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 instant the single pedal mode is activated.

Various changes in form and detail may be made to the above examples without departing from the spirit and scope of the claims and their equivalents. The examples are for illustration only and not for limitation. The description of the 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 the described systems, architectures, devices or circuits are combined in a different manner, and/or are replaced or supplemented by other components or equivalents thereof. It is intended that the scope of the disclosure be limited not by this detailed description, but rather by the claims and their equivalents. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. A vehicle controller configured to control running 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 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 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 case 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, which is a target value of the braking force in the first mode,

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 braking force for a case where the braking force of the vehicle is controlled in 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, wherein,

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 case 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, wherein,

the vehicle includes:

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

4. The vehicle controller according to claim 2, wherein,

the vehicle includes:

in the transition process, the vehicle controller is configured to control the vehicle so that the generator generates a braking force of a maximum value even when 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 storage medium storing a vehicle control program that causes a processor to execute a control process to control running of a vehicle using a first mode and a second mode, the control process comprising:

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

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

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

6. A vehicle controller configured to control travel of the vehicle using the first mode and the 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 case 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, which is a target value of the driving force in the first mode,

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

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

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 driving force and 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