Vehicle control device

Abstract

To provide a control device of a vehicle capable of suppressing a sense of incongruity of a driver when accelerating by stepping on an accelerator pedal immediately after decelerating by brake pedal operation.SOLUTION: An ECU11 is provided with a drive motor 4, a friction brake 10 for generating friction force according to the stepping amount of a brake pedal 92 to brake a vehicle 1, and an ECU11 for performing braking force suppression control for suppressing the braking force by strong regeneration of the drive motor 4 after the brake pedal 92 is released when the brake pedal 92 is released and the change speed of the operation amount of the brake pedal 92 when the release of the brake pedal 92 is started is a predetermined speed or more when the vehicle 1 is decelerated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] Patent document 1 describes an acceleration / deceleration control device that has a standard operation range within the operation stroke of the accelerator pedal where acceleration / deceleration is zero, and performs deceleration control in a first operation range where the accelerator pedal operation amount is smaller than the standard operation range, while performing acceleration control in a second operation range where the accelerator pedal operation amount is larger than the standard operation range.

[0003] When this acceleration / deceleration control device detects braking operation of a brake pedal that is provided only for deceleration operation, it shifts the standard operation range toward the first operation range, making it easier to accelerate using the accelerator pedal after braking while the vehicle is traveling.

[0004] In motor-driven vehicles such as series hybrids and electric vehicles, when acceleration / deceleration is controlled according to the amount of accelerator pedal operation, strong regenerative braking force can be used when the accelerator pedal is eased (when the accelerator pedal operation amount is small).

[0005] Generally, the braking force due to strong regeneration is controlled based on the accelerator pedal depression amount and the vehicle speed, and the smaller the accelerator pedal depression amount, the greater the braking force. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-138266 Summary of the Invention [Problem to be solved by the invention]

[0007] In such a vehicle, if the driver decelerates by operating the brake pedal and then immediately decelerates by pressing the accelerator pedal, the strong regeneration continues to decelerate the vehicle while the driver is switching from the brake pedal to the accelerator pedal, which can cause the driver to feel uncomfortable because the vehicle is being decelerated despite the driver's intention to accelerate.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle control device that can reduce the sense of discomfort felt by the driver when the driver decelerates by operating the brake pedal and then immediately accelerates by pressing the accelerator pedal. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides a vehicle control device that is equipped with a drive motor and a friction brake that generates frictional force in accordance with the amount of depression of the brake pedal to brake the vehicle, and that is capable of selecting a one-pedal drive mode that controls the output torque of the drive motor in accordance with the operation state of the accelerator pedal, thereby controlling the vehicle from acceleration / deceleration to a stop.When the brake pedal is depressed and the vehicle is decelerating, if the rate of change in the operation amount of the brake pedal when release of the brake pedal begins is equal to or greater than a predetermined rate, the control device performs braking force suppression control that suppresses the braking force caused by strong regeneration of the drive motor after the brake pedal is released. [Effects of the Invention]

[0010] In this way, according to the present invention, it is possible to suppress the sense of discomfort felt by the driver when decelerating by operating the brake pedal and then immediately accelerating by depressing the accelerator pedal. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a vehicle control device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart showing the procedure of the braking control process of the vehicle control device according to one embodiment of the present invention. [Figure 3]FIG. 3 is a time chart showing changes in deceleration due to braking control processing of a vehicle control device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] A vehicle control device according to one embodiment of the present invention is equipped with a drive motor and a friction brake that generates frictional force in accordance with the amount of depression of the brake pedal to brake the vehicle, and is capable of selecting a one-pedal drive mode that controls the output torque of the drive motor in accordance with the operation state of the accelerator pedal, thereby controlling the vehicle from acceleration / deceleration to stopping.When the brake pedal is depressed and the vehicle is decelerating, if the rate of change in the brake pedal operation amount when the brake pedal begins to be released is equal to or greater than a predetermined rate, the vehicle control device is configured to include a control unit that performs braking force suppression control that suppresses the braking force caused by strong regeneration of the drive motor after the brake pedal is released.

[0013] As a result, the vehicle control device according to one embodiment of the present invention can reduce the sense of discomfort felt by the driver when the driver decelerates by operating the brake pedal and then immediately depresses the accelerator pedal to accelerate. [Example]

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle control device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0015] In FIG. 1, a vehicle 1 equipped with a vehicle control device according to one embodiment of the present invention includes an engine 2, a generator motor 3, a drive motor 4, a generator motor inverter 7, a drive motor inverter 8, a battery 9, and an ECU (Electronic Control Unit) 11 as a control unit.

[0016] The engine 2 is formed with a plurality of cylinders. In this embodiment, the engine 2 is configured so that each cylinder undergoes a series of four strokes, which are an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.

[0017] The generator motor 3 has a rotating shaft connected to the output shaft of the engine 2. As a result, the generator motor 3 generates electric power using the driving force of the engine 2. The generator motor 3 supplies the generated electric power to a battery 9.

[0018] The drive motor 4 has a rotating shaft connected to left and right drive wheels 6 via a differential 5. As a result, the drive motor 4 functions as an electric motor that drives the drive wheels 6 with power supplied from a battery 9 via a drive motor inverter 8, and also functions as a generator that generates electricity using the reverse drive force input from the differential 5.

[0019] The generator motor inverter 7 converts the three-phase AC power generated by the generator motor 3 into DC power under the control of the ECU 11 to charge the battery 9 .

[0020] Under the control of the ECU 11, the drive motor inverter 8 converts DC power supplied from the battery 9 into three-phase AC power and supplies it to the drive motor 4. Under the control of the ECU 11, the drive motor inverter 8 converts the three-phase AC power generated by the drive motor 4 into DC power and charges the battery 9.

[0021] The battery 9 is configured by a secondary battery such as a lithium ion battery. The battery 9 is connected to the generator motor 3 and the drive motor 4, and is charged by the power generated by the generator motor 3 or the power generated by the drive motor 4 (regenerative power).

[0022] Vehicle 1 is equipped with accelerator pedal 90 as an operating pedal operated by the driver. The depression amount of accelerator pedal 90 is detected by pedal angle sensor 91. Pedal angle sensor 91 is connected to ECU 11 and is configured to set a reference angle of zero degrees when accelerator pedal 90 is released and not depressed, and to detect the angle between the released state of accelerator pedal 90 and the depressed state of accelerator pedal 90 as the depression amount of accelerator pedal 90, and transmit a signal corresponding to this angle to ECU 11.

[0023] The vehicle 1 is equipped with a brake pedal 92 that is operated by the driver. The amount of depression of the brake pedal 92 is detected by a brake pedal sensor 93. The brake pedal sensor 93 is connected to the ECU 11 and transmits a signal corresponding to the amount of depression of the brake pedal 92 to the ECU 11.

[0024] The left and right drive wheels 6 and a wheel not shown are provided with friction brakes 10. The friction brakes 10 apply a braking force to the drive wheels 6 and the wheels by friction force in response to the driver's operating pressure (pedal force) input to a brake pedal 92. The friction brakes 10 are configured to apply a braking force to the drive wheels 6 and the wheels by friction force under the control of the ECU 11.

[0025] The ECU 11 is composed of a computer unit having a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing backup data, input ports, and output ports.

[0026] The ROM of the computer unit stores various constants, various maps, and the like, as well as a program for causing the computer unit to function as the ECU 11. That is, the CPU executes the program stored in the ROM using the RAM as a work area, causing the computer unit to function as the ECU 11 in this embodiment.

[0027] To the input port of the ECU 11, various sensors including the pedal angle sensor 91, the brake pedal sensor 93, and a vehicle speed sensor 94 are connected. The vehicle speed sensor 94 detects the speed of the vehicle 1.

[0028] The output port of the ECU 11 is connected to various control targets including the engine 2, the generator motor inverter 7, the drive motor inverter 8, and the friction brake 10.

[0029] In this embodiment, the ECU 11 controls the acceleration / deceleration of the vehicle 1 based on the amount of operation of the accelerator pedal 90 .

[0030] The operation amount of the accelerator pedal 90 is successively set to a deceleration region, a dead zone region, and an acceleration region in order from the smallest operation amount.

[0031] When the operation amount of the accelerator pedal 90 is in the deceleration region, the ECU 11 accepts the operation of the accelerator pedal 90 as a deceleration operation, and controls the deceleration to increase as the operation amount of the accelerator pedal 90 decreases.

[0032] When the operation amount of the accelerator pedal 90 is in the deceleration range, the ECU 11 controls the drive motor inverter 8 to cause the drive motor 4 to output a braking force by strong regeneration. The ECU 11 controls the strong regenerative braking force of the drive motor 4 so that the braking force increases as the operation amount of the accelerator pedal 90 decreases.

[0033] When the operation amount of the accelerator pedal 90 is in the acceleration range, the ECU 11 accepts the operation of the accelerator pedal 90 as an acceleration operation, and controls the vehicle so that the greater the operation amount of the accelerator pedal 90, the greater the acceleration.

[0034] When the operation amount of the accelerator pedal 90 is in the dead band area, the ECU 11 does not accept the operation of the accelerator pedal 90 as either a deceleration operation or an acceleration operation.

[0035] For example, based on the detection results of the pedal angle sensor 91, the ECU 11 sets the state in which the accelerator pedal 90 is released and not depressed as a reference of zero degrees, and detects the amount of operation of the accelerator pedal 90 from the angle between the released state of the accelerator pedal 90 and the depressed state of the accelerator pedal 90. The amount of operation of the accelerator pedal 90 is considered to be greater as the angle increases, and less as the angle decreases. The direction of operation of the accelerator pedal 90 is considered to be a positive direction when the accelerator pedal 90 is depressed and the angle increases, and a negative direction when the accelerator pedal 90 is released and the angle decreases.

[0036] The ECU 11 stores the detection result of the brake pedal sensor 93 for each predetermined unit time, and detects the rate of change, which is the amount of change per unit time in the depression amount of the brake pedal 92.

[0037] When the brake pedal 92 is depressed and the vehicle 1 is decelerating, if the rate of change in the amount of operation of the brake pedal 92 when the brake pedal 92 begins to be released is equal to or greater than a predetermined rate, the ECU 11 performs braking force suppression control to suppress the braking force due to strong regeneration of the drive motor 4 of the vehicle 1 after the brake pedal 92 is released.

[0038] The predetermined speed is the lower limit of the release speed of the brake pedal 92 at which it is predicted that the driver will accelerate by depressing the accelerator pedal 90 immediately after releasing the brake pedal 92. Furthermore, the measurement period for the rate of change in the operation amount of the brake pedal 92 may be one unit time or may be the rate of change over several unit times, as long as the release speed of the brake pedal 92 can be measured appropriately.

[0039] As the braking force suppression control, the ECU 11 suppresses the braking force generated by the strong regeneration of the drive motor 4 so as to reduce the deceleration of the vehicle 1 to a predetermined deceleration, i.e., a reduction deceleration. The reduction deceleration is a deceleration that does not cause the driver to feel uncomfortable when switching from the brake pedal 92 to the accelerator pedal 90.

[0040] The ECU 11 may change the mitigation deceleration rate in accordance with the rate of change in the operation amount of the brake pedal 92. For example, the ECU 11 may decrease the mitigation deceleration rate as the rate of change in the operation amount of the brake pedal 92 increases.

[0041] The ECU 11 gradually reduces the deceleration caused by the strong regeneration of the drive motor 4 to a reduced deceleration rate from the time when it determines that the rate of change in the operation amount of the brake pedal 92 when the release of the brake pedal 92 begins is equal to or greater than a predetermined rate.

[0042] The ECU 11 may change the rate of change of the deceleration caused by the strong regeneration of the drive motor 4, which is reduced to the reduced deceleration rate, in accordance with the rate of change of the operation amount of the brake pedal 92. For example, the ECU 11 increases the rate of change of the deceleration caused by the strong regeneration of the drive motor 4, which is reduced to the reduced deceleration rate, as the rate of change of the operation amount of the brake pedal 92 increases.

[0043] It should be noted that while the deceleration caused by the strong regeneration of the drive motor 4 is gradually reduced to the reduced deceleration, a braking force is applied by the friction brake 10 according to the amount of depression of the brake pedal 92, and therefore the reduction in the deceleration caused by the strong regeneration of the drive motor 4 does not affect the actual deceleration.

[0044] Furthermore, since the deceleration caused by the strong regeneration of the drive motor 4 is gradually reduced to the reduced deceleration, it is possible to prevent the strong regeneration from acting too strongly for an instant when the brake pedal 92 is completely released.

[0045] The braking control process performed by the vehicle control device according to this embodiment configured as described above will be described with reference to Fig. 2. The braking control process described below starts when the ECU 11 starts operating, and is executed at preset time intervals.

[0046] In step S1, the ECU 11 determines whether the brake pedal 92 is being operated.

[0047] If it is determined that the brake pedal 92 is being operated, the ECU 11 executes the process of step S2. If it is determined that the brake pedal 92 is not being operated, the ECU 11 executes the process of step S6.

[0048] In step S2, the ECU 11 determines whether or not the release of the brake pedal 92 has started and the rate of change in the operation amount of the brake pedal 92 is equal to or greater than a predetermined rate.

[0049] When the ECU 11 determines that the release of the brake pedal 92 has started and that the rate of change in the operation amount of the brake pedal 92 is equal to or greater than a predetermined rate, the ECU 11 executes the process of step S3. When the ECU 11 determines that the release of the brake pedal 92 has started and that the rate of change in the operation amount of the brake pedal 92 is not equal to or greater than a predetermined rate, the ECU 11 executes the process of step S5.

[0050] In step S3, the ECU 11 determines that the brake is to be immediately released. After executing the process of step S3, the ECU 11 executes the process of step S4.

[0051] In step S4, the ECU 11 starts reducing the braking force by strong regeneration of the drive motor 4. After executing the process of step S4, the ECU 11 executes the process of step S5.

[0052] In step S5, the ECU 11 executes normal braking control to control the braking force of the friction brake 10 in accordance with the depression amount of the brake pedal 92. After executing the process of step S5, the ECU 11 ends the braking control process.

[0053] In step S6, the ECU 11 determines whether the accelerator pedal 90 is being operated.

[0054] If it is determined that the accelerator pedal 90 is being operated, the ECU 11 ends the braking control process. If it is determined that the accelerator pedal 90 is not being operated, the ECU 11 executes the process of step S7.

[0055] In step S7, the ECU 11 determines whether or not the brake immediate release determination has been established.

[0056] If it is determined that the immediate brake release determination has been established, the ECU 11 executes the process of step S8. If it is determined that the immediate brake release determination has not been established, the ECU 11 executes the process of step S5.

[0057] In step S8, the ECU 11 executes braking force suppression control to suppress the braking force due to strong regeneration of the drive motor 4. After executing the process of step S8, the ECU 11 ends the braking control process.

[0058] The operation of such braking control processing will be described with reference to FIG. At time t1, the brake pedal 92 starts to be released, and the rate of change in the amount of operation of the brake pedal 92 is measured.

[0059] At time t2, when it is determined that the rate of change in the amount of operation of the brake pedal 92 is equal to or greater than a predetermined rate, the braking force begins to be reduced by the strong regeneration of the drive motor 4. As a result, the deceleration due to the strong regeneration of the drive motor 4 decreases faster than the deceleration due to the friction brake 10 according to the amount of depression of the brake pedal 92, as indicated by the dotted line in the figure.

[0060] At time t3, when the brake pedal 92 is completely released, braking force suppression control is executed, and the deceleration is reduced to the reduced deceleration.

[0061] Thus, in this embodiment, when the brake pedal 92 is depressed and the vehicle 1 is decelerating, if the rate of change in the operation amount of the brake pedal 92 when the brake pedal 92 begins to be released is equal to or greater than a predetermined rate, the ECU 11 performs braking force suppression control to suppress the braking force due to strong regeneration of the drive motor 4 of the vehicle 1 after the brake pedal 92 is released.

[0062] As a result, if the rate of change in the amount of operation of the brake pedal 92 when the brake pedal 92 starts to be released is equal to or greater than a predetermined rate, the deceleration rate during the shift from the brake pedal 92 to the accelerator pedal 90 is reduced, thereby suppressing the sense of discomfort felt by the driver.

[0063] Furthermore, as braking force suppression control, the ECU 11 suppresses the braking force due to strong regeneration of the drive motor 4 so as to reduce the deceleration of the vehicle 1 to a reduced deceleration, which is a predetermined deceleration.

[0064] As a result, if the rate of change in the operation amount of the brake pedal 92 when the release of the brake pedal 92 begins is equal to or greater than a predetermined rate, the deceleration during the shift from the brake pedal 92 to the accelerator pedal 90 is reduced to a reduced deceleration, thereby suppressing the sense of discomfort felt by the driver.

[0065] Furthermore, the ECU 11 reduces the mitigation deceleration rate as the rate of change in the operation amount of the brake pedal 92 increases when the release of the brake pedal 92 begins.

[0066] As a result, when the rate of change in the amount of operation of the brake pedal 92 is fast and it is estimated that the driver wants to accelerate quickly, the deceleration is made smaller, thereby making it possible to suppress any sense of discomfort felt by the driver.

[0067] In addition, when the ECU 11 determines that the rate of change in the amount of operation of the brake pedal 92 when the brake pedal 92 begins to be released is equal to or greater than a predetermined rate, the ECU 11 gradually reduces the deceleration caused by the strong regeneration of the drive motor 4 to a reduced deceleration rate.

[0068] As a result, from the time when it is determined that the rate of change in the operation amount of the brake pedal 92 when the brake pedal 92 begins to be released is equal to or greater than a predetermined rate, the deceleration due to the strong regeneration of the drive motor 4 is gradually reduced to the reduced deceleration, thereby preventing the strong regeneration from acting too strongly for an instant when the brake pedal 92 is completely released.

[0069] Furthermore, the faster the rate of change in the amount of operation of the brake pedal 92 when the release of the brake pedal 92 begins, the faster the ECU 11 changes the rate of change in the deceleration caused by the strong regeneration of the drive motor 4 to reduce the deceleration to the reduced deceleration.

[0070] This allows the deceleration to approach the mitigated deceleration in accordance with the rate of change in the amount of operation of the brake pedal 92, and prevents strong regeneration from acting too strongly for a moment when the brake pedal 92 is completely released.

[0071] In this embodiment, an example has been described in which ECU 11 performs various determinations and calculations based on various sensor information, but this is not limited to this. Vehicle 1 may be provided with a communication unit capable of communicating with an external device such as an external server, and various determinations and calculations may be performed by the external device based on the detection information of various sensors transmitted from the communication unit. The determination results and calculation results may be received by the communication unit, and various controls may be performed using the received determination results and calculation results.

[0072] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0073] 1 vehicle 4 Drive motor 8 Drive motor inverter 9 Battery 10 Friction Brake 11 ECU (control unit) 90 Accelerator pedal 91 Pedal angle sensor 92 Brake pedal 93 Brake pedal sensor

Claims

1. A vehicle control device that is capable of selecting a one-pedal drive mode in which the output torque of the drive motor is controlled in accordance with an operation state of an accelerator pedal to control the vehicle from acceleration / deceleration to stopping, the vehicle control device comprising: a drive motor; and a friction brake that brakes the vehicle by generating a friction force in accordance with an amount of depression of a brake pedal, the one-pedal drive mode being selected in which the output torque of the drive motor is controlled in accordance with an operation state of an accelerator pedal, the one-pedal drive mode being selected in which the vehicle is controlled from acceleration / deceleration to stopping, the one-pedal drive mode being selected in accordance with an operation state of an accelerator pedal, the one-pedal drive mode being selected in which the output torque of the drive motor is controlled ... one-pedal drive mode is controlled in accordance with an operation state of an accelerator pedal, the A control device for a vehicle that includes a control unit that performs braking force suppression control to suppress braking force due to strong regeneration of the drive motor after the brake pedal is released, if the rate of change in the brake pedal operation amount when the brake pedal is depressed and the vehicle is decelerating is equal to or greater than a predetermined rate when the brake pedal starts to be released.

2. The vehicle control device according to claim 1 , wherein the control unit suppresses the braking force caused by the strong regeneration of the drive motor so as to reduce the deceleration of the vehicle to a reduced deceleration that is a predetermined deceleration, as the braking force reduction control.

3. The vehicle control device according to claim 2 , wherein the control unit reduces the mitigation deceleration as the rate of change in the operation amount of the brake pedal when the release of the brake pedal starts increases.

4. 4. The vehicle control device according to claim 2, wherein the control unit gradually reduces the deceleration caused by the strong regeneration of the drive motor to the reduced deceleration from the time when it determines that the rate of change in the operation amount of the brake pedal when the release of the brake pedal begins is equal to or greater than a predetermined rate.

5. 5. The vehicle control device according to claim 4, wherein the control unit increases the rate of change of the deceleration caused by the strong regeneration of the drive motor to reduce the deceleration to the reduced deceleration rate as the rate of change of the operation amount of the brake pedal when the release of the brake pedal starts increases.

Images