JP7767100B2 - Control device and control method - Google Patents

Description

The present invention relates to a control device and a control method.

Conventionally, hybrid vehicles are known in which the engine is driven when the running power exceeds the engine start threshold (see, for example, Patent Document 1).

International Publication No. 2011/030444

However, in the above-mentioned hybrid vehicles, driving power fluctuates depending on the driver's operation of the accelerator pedal, which can cause the engine to start and drive the vehicle on engine power at a time unintended by the driver, causing a sense of discomfort to the driver.

The present invention was made in consideration of the above, and aims to provide a control device and control method that reduces the sense of discomfort felt by the driver.

A control device according to one aspect of the embodiment controls a vehicle powered by an engine and a motor. The control device includes a control unit. When the vehicle's driving mode is in EV mode, in which the vehicle is driven without the engine being driven, and the vehicle's requested driving force based on the driver's operation amount exceeds an engine start threshold, the control unit starts the engine and transitions the driving mode to HV mode, in which the vehicle is driven using the engine and motor. When the requested driving force falls below the engine start threshold while the engine operation time since the requested driving force exceeded the engine start threshold is less than a first predetermined time, the control unit switches the driving mode to EV mode and notifies the vehicle that EV mode will continue as the driving mode.

According to one aspect of the embodiment, it is possible to reduce the sense of discomfort felt by the driver.

FIG. 1 is a schematic diagram illustrating a control method according to an embodiment. FIG. 2 is a diagram illustrating an example of the configuration of the control device according to the embodiment. FIG. 3A is a flowchart illustrating the EV mode switching control according to the embodiment. FIG. 3B is a flowchart illustrating the EV mode switching control according to the embodiment. FIG. 4 is a time chart showing an example of the running mode control according to the embodiment.

The control device and control method according to the embodiment will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to the present embodiment.

First, the control method according to the embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic diagram illustrating the control method according to the embodiment. The control method according to the embodiment is executed by the control device 10 of the vehicle C shown in FIG. 1.

Vehicle C is a hybrid vehicle that has an engine 1 and a motor 2 as drive sources. Hybrid vehicles have multiple driving modes. The multiple driving modes include an EV mode and an HV mode.

EV mode is a mode in which the vehicle C runs without the engine 1 being driven. EV mode is a mode in which the motor 2 is used as the driving source.

HV mode is a mode in which engine 1 and motor 2 are used as drive sources. For example, HV mode includes a mode in which only engine 1 is used as a drive source, and a mode in which engine 1 and motor 2 are used together as drive sources.

The HV mode may include an EV priority mode in which driving by the motor 2 is more frequently performed. In the EV priority mode, driving by the engine 1 is suppressed. For example, when the driving mode is the HV mode and the battery's state of charge (SOC) is equal to or lower than a predetermined value, the driving mode is set to an HV mode different from the EV priority mode. When the driving mode is the HV mode and the battery's SOC is higher than a predetermined value, the driving mode is set to the EV priority mode. Note that the EV priority mode may also be set by the driver operating a switch, etc.

When the driving mode is EV mode and the required driving force of vehicle C exceeds the engine start threshold, the control device 10 starts engine 1 and shifts the driving mode from EV mode to HV mode. The required driving force of vehicle C is calculated based on the driver's operation amount, for example, the operation amount of the accelerator pedal. The required driving force of vehicle C increases as the operation amount (depression amount) of the accelerator pedal increases. The control device 10 may start engine 1 based on the operation amount of the accelerator pedal instead of the required driving force. In other words, the required driving force of vehicle C may include the operation amount of the accelerator pedal. When the driving mode is set based on the operation amount of the accelerator pedal, an engine start threshold corresponding to the operation amount of the accelerator pedal is used. Note that the calculation of the required driving force of vehicle C is not limited to the operation amount of the accelerator pedal. For example, the required driving force of vehicle C may be calculated based on the operation amount of a switch, button, or lever that can change the speed.

However, even if the driver's intended required driving force for vehicle C is less than the engine start threshold, an unintended change in the amount of accelerator pedal operation by the driver may cause the actual required driving force for vehicle C to exceed the engine start threshold.

For example, if the driver does not intend to accelerate vehicle C, but the amount of accelerator pedal operation by the driver increases, the actual required driving force of vehicle C may exceed the engine start threshold.

In such a case, the required driving force of vehicle C exceeds the engine start threshold, so engine 1 is started, the driving mode is switched from EV mode to HV mode, and HV mode is continued. As a result, even though the driver wants to drive in EV mode, HV mode is executed, which is a mode different from the driver's intention, and this may cause discomfort to the driver.

Therefore, the control device 10 according to this embodiment executes the following control method.

When the driving mode is in EV mode and the required driving force exceeds the engine start threshold, the control device 10 transitions the driving mode from EV mode to HV mode (S1). Note that when the required driving force exceeds the engine start threshold, the engine 1 is started.

The control device 10 transitions the driving mode to EV mode when the required driving force falls below the engine start threshold while the engine operating time is less than a first predetermined time after the required driving force becomes equal to or greater than the engine start threshold (S2). The first predetermined time is a short, preset period of time that is longer than a second predetermined time required for engine 1 to transition to a full combustion state, and it is considered that the driver is aware that engine 1 has started after the second predetermined time. The first predetermined time is the reaction time required for the driver to notice that engine 1 has started and transition the driving mode from HV mode to EV mode. For example, the first predetermined time is approximately 1.5 seconds. Furthermore, the full combustion state of engine 1 refers to a state in which combustion is complete after the start of the internal combustion engine and engine start-up is successful.

The control device 10 notifies the driver that EV mode will continue as the driving mode (S3). For example, the control device 10 notifies the driver that EV mode will continue as the driving mode by displaying on the instrument panel that EV mode will continue or by turning on a light indicating driving in EV mode.

As a result, the control device 10 prevents the HV mode from being executed unintentionally by the driver. Furthermore, to prevent the driver from mistaking the engine stopping immediately after starting the engine 1 for an engine stall, for example, the control device 10 notifies the driver that the EV mode will continue as the driving mode. This reduces any sense of discomfort felt by the driver.

Next, the control device 10 according to the embodiment will be described with reference to Figure 2. Figure 2 is a diagram showing an example configuration of the control device 10 according to the embodiment.

The control device 10 controls the vehicle C. The control device 10 controls the engine 1 and motor 2 in accordance with the amount of accelerator pedal operation, and drives the vehicle C with a driving force that corresponds to the amount of accelerator pedal operation. The control device 10 includes a memory unit 20 and a control unit 21.

The storage unit 20 is realized, for example, by a semiconductor memory element such as RAM (Random Access Memory) or flash memory, or a storage device such as a hard disk or optical disk.

The control unit 21 is a controller, and is realized by, for example, a CPU (Central Processing Unit), MPU (Micro Processing Unit), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), etc., by executing various programs (equivalent to examples of information processing programs) stored in the internal storage device of the control device 10 using a storage area such as RAM as a working area.

The control unit 21 includes an acquisition unit 22, a calculation unit 23, a measurement unit 24, a determination unit 25, a switching unit 26, and a notification unit 27. The acquisition unit 22, calculation unit 23, measurement unit 24, determination unit 25, switching unit 26, and notification unit 27 are not limited to this configuration, and may be integrated or separated.

The acquisition unit 22 acquires a signal related to the accelerator pedal operation amount from the accelerator pedal sensor 30. The calculation unit 23 calculates the required driving force of the vehicle C based on the accelerator pedal operation amount.

When the required driving force becomes equal to or greater than the engine start threshold, the measurement unit 24 measures the engine operating time after the required driving force becomes equal to or greater than the engine start threshold. When the required driving force becomes less than the engine start threshold, the measurement unit 24 resets the engine operating time at a predetermined timing. For example, the measurement unit 24 resets the engine operating time after determining that the engine operating time is equal to or less than a first predetermined time. The measurement unit 24 resets the engine operating time after determining whether the engine operating time is less than a second predetermined time.

The determination unit 25 determines whether the current driving mode is EV mode. The determination unit 25 determines whether the required driving force is equal to or greater than the engine start threshold. When the required driving force becomes equal to or greater than the engine start threshold, the driving mode is switched from EV mode to HV mode, and the required driving force becomes less than the engine start threshold, the determination unit 25 determines whether the engine operating time in HV mode is equal to or less than a first predetermined time. Furthermore, when the required driving force becomes equal to or greater than the engine start threshold, the driving mode is switched from EV mode to HV mode, and the required driving force becomes less than the engine start threshold, the determination unit 25 determines whether the engine operating time in HV mode is less than a second predetermined time.

The switching unit 26 switches the driving mode between EV mode and HV mode. Specifically, when the current driving mode is EV mode and the required driving force becomes equal to or greater than the engine start threshold, the switching unit 26 transitions the driving mode from EV mode to HV mode.

After the requested driving force becomes equal to or greater than the engine start threshold and the driving mode is shifted from EV mode to HV mode, the switching unit 26 shifts the driving mode from HV mode to EV mode if the requested driving force becomes less than the engine start threshold and the engine operating time is equal to or less than a first predetermined time.

The switching unit 26 executes engine 1 stop control when the engine operating time is equal to or greater than the second predetermined time and equal to or less than the first predetermined time. If the engine operating time is less than the second predetermined time, the switching unit 26 halts engine 1 start control and prevents engine 1 from transitioning to a complete combustion state.

When the driving mode is changed from EV mode to HV mode, the switching unit 26 starts the engine 1. When the driving mode is changed from HV mode to EV mode, the switching unit 26 stops the engine 1.

The notification unit 27 notifies the driver that EV mode will continue as the driving mode when the required driving force exceeds the engine start threshold, the driving mode is shifted from EV mode to HV mode, and the required driving force falls below the engine start threshold and the driving mode is shifted from HV mode to EV mode while the engine operating time is greater than or equal to the second predetermined time and less than or equal to the first predetermined time. For example, the notification unit 27 displays on the instrument panel that EV mode will continue. Note that the notification unit 27 may also notify the driver that EV mode will continue as the driving mode by voice.

The notification unit 27 does not issue a notification when the required driving force is equal to or greater than the engine start threshold, the driving mode is shifted from EV mode to HV mode, the engine operating time is less than a second predetermined time, the required driving force is less than the engine start threshold, and the driving mode is shifted from HV mode to EV mode.

Next, the EV mode switching control according to this embodiment will be described with reference to the flowcharts in Figures 3A and 3B. Figures 3A and 3B are flowcharts explaining the EV mode switching control according to this embodiment.

The control device 10 determines whether the current driving mode is EV mode (S100). If the current driving mode is not EV mode (S100: No), i.e., if the driving mode is HV mode, the control device 10 ends this processing.

If the current driving mode is EV mode (S100: Yes), the control device 10 acquires the accelerator pedal operation amount (S101). The control device 10 calculates the required driving force based on the accelerator pedal operation amount (S102).

The control device 10 determines whether the required driving force is equal to or greater than the engine start threshold (S103). If the required driving force is less than the engine start threshold (S103: No), the control device 10 ends this processing. The driving mode remains in EV mode.

If the required driving force is equal to or greater than the engine start threshold (S103: Yes), the control device 10 switches the driving mode to HV mode (S104). In other words, if the driving mode is EV mode and the required driving force is equal to or greater than the engine start threshold, the control device 10 transitions the driving mode from EV mode to HV mode.

Following S104, the control device 10 measures the engine operating time after the required driving force becomes equal to or greater than the engine start threshold (S105).

The control device 10 acquires the accelerator pedal operation amount (S106). The control device 10 calculates the required driving force based on the accelerator pedal operation amount (S107). The control device 10 calculates the required driving force in HV mode.

The control device 10 determines whether the required driving force is less than the engine start threshold (S108). Specifically, the control device 10 determines whether the required driving force becomes less than the engine start threshold after the required driving force becomes equal to or greater than the engine start threshold and the driving mode changes to HV mode.

If the required driving force is equal to or greater than the engine start threshold (S108: No), the control device 10 returns to step S105 and repeats the above process. That is, if the driving mode is HV mode and the required driving force is equal to or greater than the engine start threshold, the control device 10 continues measuring the engine operating time in HV mode.

If the required driving force is less than the engine start threshold in S108 (S108: Yes), the control device 10 determines whether the engine operating time is less than or equal to the first predetermined time (S109).

If the engine operating time is longer than the first predetermined time (S109: No), the control device 10 ends this processing. If the engine operating time is longer than the first predetermined time, the driving mode is maintained in HV mode. Note that if it is determined that the engine operating time is longer than the first predetermined time, the engine operating time is reset.

If the engine operating time is less than or equal to the first predetermined time (S109: Yes), the control device 10 switches the driving mode to EV mode (S110). That is, after the required driving force becomes equal to or greater than the engine start threshold and the driving mode changes to HV mode, if the required driving force falls below the engine start threshold within a short period of time during which the engine operating time is less than or equal to the first predetermined time, the control device 10 switches the driving mode back to EV mode and continues in EV mode.

The control device 10 determines whether the engine operation time is less than the second predetermined time (S111). If the engine operation time is equal to or greater than the second predetermined time (S111: No), the control device 10 notifies the driver that the driving mode will continue in EV mode (S112).

If the engine operation time is less than the second predetermined time (S111: Yes), the control device 10 ends the current processing. If the engine operation time is less than the second predetermined time, the control device 10 ends the current processing without notifying the driver that the driving mode will continue in EV mode. Note that the engine operation time is reset after the determination in step S111.

If the engine operating time is less than the second predetermined time, the driving mode is shifted from HV mode to EV mode before the engine 1 transitions to a full combustion state, making it difficult for the driver to notice that the driving mode has changed from EV mode to HV mode and then from HV mode to EV mode. Therefore, the control device 10 ends the processing without notifying the driver that the driving mode has been shifted to EV mode.

Next, an example of driving mode control according to the embodiment will be described with reference to FIG. 4. FIG. 4 is a time chart showing an example of driving mode control according to the embodiment. Here, it is assumed that vehicle C is driving in EV mode, the driver intends to maintain a constant amount of accelerator pedal operation, and the driver's desired driving force is constant.

Although the driver's intended required driving force remains constant, the actual required driving force changes depending on the driver's slight changes in accelerator pedal pressure.

At time t1, when the requested driving force increases against the driver's will and exceeds the engine start threshold, the driving mode is shifted from EV mode to HV mode. Also, because the requested driving force has exceeded the engine start threshold, engine 1 starts and the engine rotation speed increases.

At time t2, when the engine operating time is equal to or greater than the second predetermined time and equal to or less than the first predetermined time, if the required driving force falls below the engine start threshold, the driving mode is shifted from HV mode to EV mode. Because the engine operating time is equal to or greater than the second predetermined time and equal to or less than the first predetermined time, the driving mode is shifted from HV mode to EV mode, and a notification is issued that EV mode will be maintained.

The control device 10 controls a vehicle C driven by an engine 1 and a motor 2. The control device 10 includes a control unit 21. When the driving mode of the vehicle C is in an EV mode in which the vehicle C is driven without the engine 1 being driven, and the requested driving force of the vehicle C based on the amount of operation of the accelerator pedal reaches or exceeds an engine start threshold, the control unit 21 starts the engine 1 and transitions the driving mode to an HV mode in which the vehicle C is driven using the engine 1 and the motor 2. If the engine operating time after the requested driving force reaches or exceeds the engine start threshold is less than a first predetermined time and the requested driving force falls below the engine start threshold, the control unit 21 switches the driving mode to the EV mode, and if the engine operating time is greater than or equal to a second predetermined time, the control unit 21 notifies the vehicle that the EV mode will continue as the driving mode.

As a result, if the required driving force temporarily exceeds the engine start threshold against the driver's intention, the control device 10 can switch the driving mode to EV mode and continue driving in EV mode. Therefore, the control device 10 can drive the vehicle C in a driving mode that corresponds to the driver's intention, and can reduce the sense of discomfort felt by the driver. The control device 10 can also increase the frequency of driving in EV mode, thereby reducing fuel consumption by the engine 1. Furthermore, for example, when the vehicle C is driving in a residential area, the control device 10 can reduce the noise generated by the operation of the engine 1.

In addition, the control device 10 notifies the driver that EV mode will continue as the driving mode, thereby making the driver aware that EV mode will continue. Therefore, the control device 10 can prevent the driver from feeling uncomfortable when the driving mode switches from EV mode to HV mode and then from HV mode to EV mode in a short period of time.

If the engine operating time is less than a second predetermined time, which is shorter than the first predetermined time, the control unit 21 halts engine 1 start control and does not issue a warning. The second predetermined time is the time required for engine 1 to transition to a full combustion state.

As a result, if the required driving force falls below the engine start threshold before engine 1 transitions to a full explosion state, control device 10 can suppress fuel consumption by engine 1 by halting engine 1 start. Furthermore, because the driver does not feel engine 1 starting, control device 10 does not notify the driver that the driving mode will continue in EV mode, thereby suppressing the provision of unnecessary information to the driver and preventing the driver from feeling uncomfortable.

When the engine operating time is equal to or longer than the second predetermined time and equal to or shorter than the first predetermined time, and the requested driving force falls below the engine start threshold, the control unit 21 executes stop control of the engine 1 and issues a notification.

As a result, if engine 1 transitions to a full combustion state and the required driving force falls below the engine start threshold immediately after engine 1 transitions to the full combustion state, control device 10 notifies the driver that EV mode will continue as the driving mode. Therefore, control device 10 notifies the driver that the stop of engine 1 is not due to, for example, an engine stall, and can prevent the driver from feeling uncomfortable.

As a modified example, the control device 10 according to the modified example may transition the driving mode to EV-priority mode when the required driving force becomes equal to or greater than the engine start threshold and the driving mode changes to HV mode, and then when the required driving force becomes less than the engine start threshold and the engine operating time is equal to or less than a third predetermined time and is longer than the first predetermined time. The third predetermined time is longer than the first predetermined time. For example, the third predetermined time is approximately 5 seconds.

As a result, the control device 10 can suppress driving by the engine 1 immediately after the required driving force exceeds the engine start threshold, thereby reducing fuel consumption by the engine 1. Furthermore, for example, when the vehicle C is driving in a residential area, the control device 10 can suppress noise caused by the operation of the engine 1.

Further advantages and modifications may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

REFERENCE SIGNS LIST 1 Engine 2 Motor 10 Control device 21 Control unit 22 Acquisition unit 23 Calculation unit 24 Measurement unit 25 Determination unit 26 Switching unit 27 Notification unit C Vehicle

Claims (8)

A control device that controls a vehicle driven by an engine and a motor,
a control unit that, when a driving mode of the vehicle is an EV mode in which the vehicle is driven without the engine being driven, starts the engine and transitions the driving mode to an HV mode in which the vehicle is driven using the engine and the motor when a required driving force of the vehicle based on an operation amount of a driver becomes equal to or greater than an engine start threshold;
When the required driving force becomes equal to or greater than the engine start threshold and the vehicle's driving mode transitions from the EV mode to the HV mode, and the engine operating time is equal to or less than a first predetermined time and the required driving force becomes less than the engine start threshold, the control unit stops the engine by returning the driving mode to the EV mode and notifies the driver that the engine stop is not due to an engine stall . The control device described in claim 1, wherein the control unit suspends engine start control and does not issue the notification when the engine operating time is less than a second predetermined time that is shorter than the first predetermined time. The control device described in claim 2, wherein the second predetermined time is the time it takes for the engine to transition to a complete combustion state. The control device described in claim 2 or 3, wherein the control unit executes engine stop control and issues the notification when the engine operating time is equal to or longer than the second predetermined time and the required driving force becomes less than the engine start threshold when the engine operating time is equal to or shorter than the first predetermined time. A control device according to any one of claims 1 to 4, wherein the control unit transitions the driving mode to a mode in which EV driving is prioritized within the HV mode when the engine operating time is equal to or shorter than a third predetermined time that is longer than the first predetermined time and is also longer than the first predetermined time. A control device that controls a vehicle driven by an engine and a motor,
The vehicle has, as driving modes, an EV mode in which the vehicle is driven without the engine being driven, and an HV mode in which, when a required driving force of the vehicle based on an operation amount of a driver becomes equal to or greater than an engine start threshold, the engine is started and the vehicle is driven using the engine and the motor,
When the required driving force becomes equal to or greater than the engine start threshold, causing the vehicle's driving mode to transition from the EV mode to the HV mode, and the required driving force becomes less than the engine start threshold before the engine transitions to a full combustion state, the control device stops engine start control. A control method performed by a control device that controls a vehicle driven by an engine and a motor,
a transition step of starting the engine and transitioning the driving mode to an HV mode in which the vehicle is driven using the engine and the motor when a required driving force of the vehicle becomes equal to or greater than an engine start threshold value when the driving mode of the vehicle is an EV mode in which the vehicle is driven without the engine being driven,
The transition process includes a control method in which, when the required driving force becomes equal to or greater than the engine start threshold and the vehicle's driving mode transitions from the EV mode to the HV mode, and when the engine operating time is equal to or less than a first predetermined time and the required driving force becomes less than the engine start threshold, the driving mode is returned to the EV mode to stop the engine , and an alert is issued that the engine stop is not due to an engine stall . A control method performed by a control device that controls a vehicle driven by an engine and a motor,
The vehicle has, as driving modes, an EV mode in which the vehicle is driven without the engine being driven, and an HV mode in which, when a required driving force of the vehicle based on an operation amount of a driver becomes equal to or greater than an engine start threshold, the engine is started and the vehicle is driven using the engine and the motor,
a control method for stopping engine start control when the required driving force becomes equal to or greater than the engine start threshold, causing the vehicle's driving mode to transition from the EV mode to the HV mode, and when the required driving force becomes less than the engine start threshold before the engine transitions to a full combustion state.