Control device of vehicle

Abstract

To provide a control device that can eliminate or reduce shock occurring when breaking and stopping a vehicle by energy regeneration.SOLUTION: A control device is configured to make regenerative torque caused by energy regeneration that is performed based on reduction of accelerator operation amounts act as braking force, and to be able to select a normal traveling mode in which the regenerative torque becomes equal to predetermined torque and a regeneration-increase traveling mode in which the regenerative torque becomes larger than torque in the normal traveling mode. A controller that controls the regenerative torque comprises: a rate processing part (step S6) that performs rate processing for the regenerative torque; a mode determining part (step S4) that determines the selected traveling mode; and a rate processing changing part (step S5) that reduces variations in the regenerative torque by the rate processing executed by the rate processing part more than when the normal traveling mode is selected, on the basis of the fact that the regeneration increase traveling mode is selected.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vehicle control device capable of performing braking using negative torque associated with energy regeneration during deceleration. [Background technology]

[0002] In an electric vehicle (BEV, HEV, or PHEV) having an electric motor as a driving force source, it is common to perform energy regeneration by driving a generator with the kinetic energy of the vehicle when decelerating and charging the generated power to an electricity storage device (battery). In this case, the torque driving the generator becomes the braking force, so that control may be performed to further increase the regenerative braking force depending on the driving conditions of the vehicle. Patent Document 1 describes a vehicle that performs so-called strong regenerative control to increase such regenerative braking force. The strong regenerative control described in Patent Document 1 is a control that is performed when a specific switch is turned on and the control mode is selected, and when the control mode is set, the regenerative braking force is increased more than in normal times. More specifically, when the accelerator pedal is released and the accelerator opening becomes "0" while the vehicle is running in a driving mode that performs strong regenerative control, the regenerative braking force is controlled to be larger than the regenerative braking force when the driving mode that performs strong regenerative control is not set. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-112204 A Summary of the Invention [Problem to be solved by the invention]

[0004] Electric vehicles, like general engine vehicles equipped with automatic transmissions, are usually configured to generate creep torque when temporarily stopped. If the above-mentioned strong regenerative control is executed in this type of electric vehicle, there is a possibility that the shock will be large when the vehicle is stopped by operating the brakes. For example, when the accelerator pedal is pressed back while the motor generator is generating driving torque and braking torque and the vehicle is running, the motor generator is made to function as a generator to perform regenerative braking. When the vehicle speed gradually decreases due to regenerative braking and braking by operating the brakes in addition to this, and finally the vehicle speed becomes "0" and the vehicle stops, the current is controlled so that the motor generator functions as a motor, and the above-mentioned creep torque is generated. Therefore, the torque of the vehicle is reversed from braking torque to driving torque. In that case, when the above-mentioned strong regenerative control is executed, the braking torque is larger than usual, so the torque change amount or torque step when switching from braking torque to creep torque is larger than usual. Since there is necessary or unavoidable backlash and backlash in the transmission mechanism of a vehicle, when the torque is significantly reversed, a shock occurs due to the backlash and backlash, and when the above-mentioned strong regenerative control is being performed, such a shock can become large.

[0005] The present invention has been made in consideration of the above technical problems, and aims to provide a control device that can eliminate or reduce the shock that occurs when braking and stopping the vehicle by using energy regeneration. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a vehicle control device that is configured to perform energy regeneration based on a reduction in accelerator operation amount while driving, and to cause a regenerative torque associated with the energy regeneration to act as a braking force, so as to be able to select between a normal driving mode in which the regenerative torque is a predetermined torque, and a regenerative increased driving mode in which the regenerative torque is greater than the normal driving mode, and is characterized in that the vehicle control device has a controller that controls the regenerative torque, and the controller is equipped with a rate processing unit that performs rate processing to reduce the amount of change in the regenerative torque, a mode determination unit that determines which driving mode is selected from the normal driving mode and the regenerative increased driving mode, and a rate processing change unit that, based on the determination by the mode determination unit that the regenerative increased driving mode has been selected, increases the reduction in the amount of change in the regenerative torque due to the rate processing executed by the rate processing unit compared to when the normal driving mode is selected. Effect of the Invention

[0007] According to the present invention, when the accelerator operation amount is reduced to perform braking by regenerative torque, if the driving mode selected at that time is the regenerative augmented driving mode in which the regenerative torque is greater than that in the normal driving mode, the amount of change in the regenerative torque is more moderate than when the normal driving mode is selected. That is, the change in braking force associated with energy regeneration is moderated. As a result, when the vehicle stops with regenerative braking or when creep torque acting in the opposite direction to the braking torque is generated as the vehicle stops, the change in torque becomes gentle, and backlash and the like are eliminated over time, so that shock can be avoided or reduced. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a block diagram showing a functional configuration of a controller according to an embodiment of the present invention. [Diagram 2] 4 is a flowchart illustrating an example of control executed in the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Next, the present invention will be described based on the embodiment shown in the drawings. Note that the embodiment described below is merely one example of a specific embodiment of the present invention, and is not intended to limit the present invention.

[0010] The vehicle targeted in the embodiment of the present invention is a vehicle configured to use regenerative torque, which is a negative torque resulting from energy regeneration, as a braking force. Such energy regeneration is generally performed by converting the kinetic energy of the vehicle into electricity and storing it, and therefore typical examples of the vehicle targeted in the embodiment of the present invention are electric vehicles (BEVs) and hybrid vehicles (HEVs, PHEVs) equipped with a motor (sometimes called a motor generator) with a power generating function as a driving force source. Naturally, the vehicle also has mechanisms required for running, such as an accelerator pedal for accelerating and decelerating, a brake pedal for braking and a brake device mainly based on friction brakes, and a steering device for changing the running direction from left to right, just like a conventional general vehicle.

[0011] Fig. 1 is a block diagram for explaining a system for accelerating, decelerating, and braking in this type of vehicle. A motor 1 with a power generating function is provided as a driving force source, and the motor 1 and wheels (drive wheels) 2 are connected via a transmission mechanism (not shown), and the system is configured to transmit the driving torque output by the motor 1 to the wheels 2, and also transmit torque based on the inertial force of the vehicle's running from the wheels 2 to the motor 1 to rotate the motor 1. The reaction torque against the torque transmitted from the wheels 2 to the motor 1 to rotate the motor 1 is the regenerative torque.

[0012] In addition, the wheels 2 are provided with brakes 3 that act to stop the rotation of the wheels 2. The brakes 3 are configured to perform braking by generating frictional force using, for example, hydraulic pressure, and are configured so that the braking force can be appropriately controlled.

[0013] An accelerator pedal 4 is provided for accelerating and decelerating the vehicle, and the motor torque, such as the drive torque and regenerative torque, generated by the motor 1 is controlled in accordance with the depression amount of the accelerator pedal 4 (accelerator opening or accelerator operation amount). A controller (powertrain system arbitrator) 5 is provided for performing this control. The controller 5 is mainly composed of a microcomputer consisting of a calculation element (CPU), memory elements (RAM and ROM), an input / output interface, etc., and is configured to perform calculations according to a pre-stored program using input data and pre-stored data, and to output the results of the calculations as a control command signal. The functional configuration of this controller 5 is shown as a block diagram in FIG. 1.

[0014] A required torque calculation unit 5a is provided to calculate the motor torque to be output by the motor 1 based on the accelerator opening. In addition to the accelerator opening, data is input from a system information input unit 5b to the required torque calculation unit 5a. The system information includes data indicating the running state of the vehicle, such as the rotation speed and vehicle speed of the motor 1, and information on the running mode. The running modes in the embodiment of the present invention are a plurality of running modes in which the regenerative torque is made large and small, such as a normal running mode in which the regenerative torque is set to a normal value and the regenerative increase running mode in which the regenerative torque is made larger than the normal value. The normal value of the regenerative torque and the increased value obtained by increasing the regenerative torque may be a constant value determined in advance by design or a constant value determined for each motor rotation speed. The system information input unit 5b corresponds to a mode determination unit in the embodiment of the present invention.

[0015] The required torque calculation unit 5a calculates the driving torque and the regenerative torque based on the accelerator opening, the vehicle speed input from the system information input unit 5b, the selected (or set) driving mode, and other data. For example, when the accelerator opening is large enough to increase the vehicle speed, the driving torque is calculated according to the accelerator opening, and conversely, when the accelerator pedal 4 is released and the accelerator opening is small enough to decrease the vehicle speed, the regenerative torque is calculated according to the accelerator opening. Furthermore, when the accelerator pedal 4 is released and the accelerator opening is "0" (accelerator off), a predetermined regenerative torque is calculated. The regenerative torque when the accelerator is off differs depending on the selected driving mode, and when the normal driving mode is selected, in other words when the regenerative augmented driving mode is not selected, the regenerative torque (regenerative braking force) is set to a predetermined normal value. On the other hand, when the regenerative augmented driving mode is selected, the regenerative torque is set to a value larger than the normal value so that the regenerative braking force is large. The driving mode is selected by operating a switch (not shown).

[0016] A torque arbitration unit 5c is provided for arbitrating the regenerative torque calculated by the required torque calculation unit 5a with the required braking force calculated based on the depression amount of the brake pedal 6. Braking of the vehicle is achieved by the regenerative torque and the braking torque generated by the brake 3. On the other hand, when the brake pedal 6 is depressed, the driver's braking request is reflected in the depression amount or pressure of the brake pedal 6. When regenerative braking is performed, part of the braking request is handled by the regenerative braking and the other part is handled by the brake 3. Therefore, it is necessary to arbitrate the regenerative torque and the braking torque by the brake 3 so as to satisfy the driver's braking request, and such arbitration is performed by the torque arbitration unit 5c.

[0017] 1 shows a block diagram of a brake pedal demand controller 7 that controls the brake 3 based on the amount of operation of the brake pedal 6. The brake pedal demand controller 7 has a regenerative cooperative control unit 7a for executing braking by the brake 3 and braking by the regenerative torque in a coordinated manner. The brake pedal demand controller 7 is configured to obtain a brake braking force obtained by subtracting the braking force by the regenerative torque from the braking force obtained from the amount of operation of the brake pedal 6, for example, and to output a hydraulic pressure command required to achieve the brake braking force to the brake 3. Note that the rotational speed (wheel speed) of the wheels 2 is input to the regenerative cooperative control unit 7a in order to feedback control the frictional force of the brake 3 or the hydraulic pressure that generates the frictional force.

[0018] The torque arbitration unit 5c performs arbitration between regenerative braking and braking based on data exchanged with the regenerative cooperative control unit 7a, and determines the braking force (regenerative torque) to be handled by regenerative braking. Since energy efficiency (electricity cost or fuel consumption) of the vehicle is improved by performing energy regeneration through regenerative braking, energy regeneration is generally prioritized and as much energy regeneration as possible is performed. Therefore, when the regenerative boost driving mode is selected or set, the regenerative braking force is larger than when the normal driving mode is selected or set.

[0019] A processing unit is provided that performs a slow-change process on the regenerative torque found by the torque mediation unit 5c and outputs it as a control command value for the motor 1, and one example of this is the torque rate processing unit 5d. The torque rate processing is, in essence, signal processing that delays the degree of change or the rate of change of the regenerative torque, and data related to the driving mode is input to the torque rate processing unit 5d from the above-mentioned system information input unit 5b, and the content of the torque rate processing is changed according to the selected or set driving mode. Therefore, the torque rate processing unit 5d corresponds to the rate processing change unit in the embodiment of the present invention. Specifically, when the regenerative increase driving mode is selected, the degree of mitigation of the amount of change in the regenerative torque is increased (the torque rate processing amount is increased or the torque rate application range is expanded) compared to when the normal driving mode is selected, and the change in the motor torque is made gentler.

[0020] An example of the control executed by the controller 5 will be described with reference to the flowchart shown in Fig. 2. The routine shown in Fig. 2 is repeatedly executed at predetermined short intervals while the vehicle is running. First, various information is read (step S1). The information is data acquired by the accelerator opening and the above-mentioned system information input unit 5b, and is data indicating the running state of the vehicle, such as the number of rotations of the motor 1, the vehicle speed, and the operation amount of the brake pedal 6.

[0021] Next, it is determined whether or not there is a regeneration request from the brake, that is, whether or not there is a request to perform regenerative braking (step S2). If the result of the determination in step S2 is "no", the routine shown in FIG. 2 is terminated without performing any particular control. On the other hand, if the result of the determination in step S2 is "yes", it is determined whether or not the vehicle's operating state or control state is in the regenerative cooperative region (step S3). In this determination, the result is "yes" when, for example, the accelerator is off and the brake pedal 6 is depressed. If the result of the determination in step S3 is "no", the routine shown in FIG. 2 is terminated without performing any particular control. On the other hand, if the result of the determination in step S3 is "yes", it is determined (step S4) which driving mode has been selected or set. This determination is a determination of whether the above-mentioned normal driving mode or the regenerative boost driving mode has been selected or set, and if it is determined that the regenerative boost driving mode has been selected or set, the rate processing is changed.

[0022] This change in rate processing is a change in the processing content in the torque rate processing unit 5d described above, and when the regenerative increase driving mode is selected, a predetermined coefficient or gain is changed, or the torque rate application range is expanded, so that the degree to which the amount of change in the regenerative torque is mitigated is greater than when the normal driving mode is selected.

[0023] Then, in the following step S6, rate processing of the regenerative torque is executed. This rate processing is executed even if it is determined in the above step S4 that the normal driving mode is selected or set. That is, if the torque rate processing is set according to the regenerative augmented driving mode, the change in the regenerative torque is mitigated by the processing, and if the normal driving mode is selected or set and the torque rate processing corresponding to the normal driving mode is set, the change in the regenerative torque is not mitigated in particular, but the regenerative torque is changed by a predetermined change amount. After that, the routine of FIG. 2 is temporarily terminated.

[0024] Therefore, according to the control device of the present invention which is equipped with the controller 5 shown in FIG. 1 and executes the control shown in FIG. 2, when the vehicle is braked heavily using regenerative torque, even if the vehicle stops and no longer has a reaction force against the braking force, or the regenerative torque generates a creep torque in the opposite direction, the change in the regenerative torque is mitigated compared to when decelerating in normal driving mode, so that shocks caused by rattle, backlash, etc. can be eliminated or reduced.

[0025] It should be noted that the above-described embodiments are merely intended to specifically explain the present invention, and the present invention can be modified and implemented as appropriate within the scope of its purpose, and these embodiments also fall within the scope of the present invention. [Explanation of symbols]

[0026] 1 Motor 2 wheels 3. Brake 4. Accelerator pedal 5. Controller 5a Required torque calculation section 5b System information input section 5c Torque adjustment section 5d Torque rate processing section 6. Brake pedal 7 Brake pedal demand controller 7a Regenerative coordination control unit

Claims

[Claim 1] A control device for a vehicle configured to perform energy regeneration based on a reduction in an accelerator operation amount during driving, and to cause a regenerative torque associated with the energy regeneration to act as a braking force, and to select a normal driving mode in which the regenerative torque is a predetermined torque, and an increased regenerative driving mode in which the regenerative torque is greater than the normal driving mode, A controller for controlling the regenerative torque is provided. The controller: a rate processing unit that performs rate processing to reduce a change amount of the regenerative torque; a mode determination unit that determines a selected driving mode from the normal driving mode and the regenerative power increase driving mode; a rate processing change unit that increases the reduction in the amount of change in the regenerative torque due to the rate processing executed by the rate processing unit, based on the determination by the mode determination unit that the regenerative torque-increasing driving mode is selected, compared to when the normal driving mode is selected. A vehicle control device comprising:

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