JP2019152308A - Braking power control device - Google Patents

Abstract

To provide a braking power control device for vehicle capable of suitably obtaining braking power that a user requests.SOLUTION: A braking power control device for vehicle comprises: a free-wheeling state detection part which detects a free-wheeling state being entered, the free-wheeling state being a state in which no accelerator operation is performed and a braking action is not performed during a travel of the vehicle; a braking power estimation part which estimates requested braking power as braking power that a user requests once the free-wheeling state detection part detects the free-wheeling state being entered; and a line pressure setting part which sets line pressure of an automatic transmission of the vehicle higher when the requested braking power that the braking power estimation part estimates is equal to or larger than a predetermined threshold than when less than the threshold so as to generate braking power of the vehicle.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a braking force control device mounted on a vehicle or the like.

  In a vehicle, it is important for ease of driving to perform acceleration / deceleration as desired by a user without delay, and various techniques have been proposed. Japanese Patent Application Laid-Open No. 2004-133867 is a control device for an automatic transmission, which normally suppresses the line pressure, which is the hydraulic pressure of hydraulic oil provided to various engagement friction elements in the automatic transmission, to obtain a sufficient operating pressure at the time of shifting. It is disclosed that the fuel efficiency and the shift response can be made compatible by increasing the value when there is a possibility of not being present. Patent Document 2 discloses that in a fuel cut control device, when the fuel cut at the time of deceleration is prohibited to prevent catalyst deterioration at a high catalyst temperature, the deceleration force is supplemented by an alternator, an air conditioner, a brake, a gear shift, and the like. Yes. Patent Document 3 distributes a control target determined according to an operation amount of a driver to a driving system and a control system according to a handling ratio in a vehicle integrated control device, while distributing it to a stabilization system. It discloses that the delay is reduced while transmitting the previous control target and calculating the correction process, thereby making it unnecessary to synchronize the distribution value of the control target by the stabilization system and maintaining the fail-safe property.

Japanese Patent Laid-Open No. 2007-232077 JP-A-10-280990 JP 2006-297994 A

  In response to the demand for lower fuel consumption in vehicles, the engine friction has been reduced. As disclosed in Patent Document 1, if the line pressure of the automatic transmission is suppressed, the effect of engine braking is reduced, and the braking force requested by the user may not be obtained.

  In view of the above problems, an object of the present invention is to provide a vehicle braking force control device that can suitably obtain a braking force requested by a user.

  In order to solve the above-described problem, an aspect of the present invention is a braking force control device for a vehicle, which is in a state where an accelerator operation is not performed and a brake operation is not performed while the vehicle is traveling. A coasting state detection unit that detects that the state is established, and a coasting state detection unit that detects that the coasting state is established, and a braking force estimation unit that estimates a requested braking force that is a braking force requested by the user; If the required braking force estimated by the braking force estimation unit is greater than or equal to a predetermined threshold, the line pressure of the automatic transmission of the vehicle is set to a higher value and the braking force of the vehicle A braking force control device including a line pressure setting unit to be generated.

  Thereby, the required braking force requested by the user when the coasting state is established is estimated, and the line pressure is set high according to the estimation result to generate the braking force. Thereby, it is possible to suitably obtain the braking force requested by the user.

  According to the present invention, as described above, the braking force requested by the user at the time when the coasting state is established is estimated, and the braking force requested by the user is suitably obtained by increasing the line pressure accordingly. A braking force control device for a vehicle that can be provided can be provided.

1 is a functional block diagram of a braking force control device according to an embodiment of the present invention and its peripheral portion. The sequence diagram which shows the process of the braking force control apparatus which concerns on one Embodiment of this invention. The graph which shows an example of the time change of various state quantity and control quantity concerning one embodiment of the present invention

(Overview)
In the braking force control apparatus according to the present invention, the required braking force from the user in the coasting state is estimated based on information from various sensors. When the estimated required braking force is larger than the threshold value, the line pressure of the automatic transmission is increased to generate the braking force according to the user's request, as compared to the case where it is not.

(Embodiment)
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

<Configuration>
FIG. 1 shows a functional block diagram of the braking force control apparatus 100 according to the present embodiment and its peripheral part. The braking force control device 100 includes a coasting state detection unit 11, a braking force estimation unit 12, and a line pressure setting unit 13. The braking force control device 100 is mounted on a vehicle and connected to various sensor groups 200 and an automatic transmission 300. The braking force control apparatus 100 acquires information representing various states of the vehicle and the surroundings of the vehicle detected by the sensor group 200, and controls the automatic transmission 300 based on the information.

<Processing>
Below, the process which each part of the braking force control apparatus 100 performs is demonstrated. FIG. 2 is a sequence diagram for explaining the processing. Moreover, FIG. 3 is a figure which shows an example of the time change of the accelerator opening degree, request | requirement braking force, an engine speed, a line pressure, and an actual output torque which are the various state amount and control amount which concern on this process. This process is started when the user performs a coasting operation without performing the accelerator operation and performing the brake operation.

  (Step S101): The coasting state detection unit 11 acquires information indicating that the accelerator opening and the brake depression amount are 0 from the accelerator opening sensor and the brake pedal sensor included in the sensor group 200, respectively, and coasts Detects that the condition has been established.

  (Step S102): Based on the state acquired from the sensor group 200, the braking force estimation unit 12 estimates a required braking force that is a braking force requested by the user. The state acquired from the sensor group includes changes in the accelerator and brake operation amount and change speed of the user, engine state, vehicle speed, acceleration, vehicle position information, obstacle information around the vehicle by millimeter wave radar, and selection of drive mode Examples include, but are not limited to: In addition to these, a state such as a shift position of the automatic transmission 300 may be used.

  As an example of the processing in step S102, a method for estimating the required braking force based on the accelerator operation by the user will be described. As shown in FIG. 3, the braking force estimation unit 12 estimates that the required braking force of the user is large when the accelerator opening decreases from 50% to 0% at a predetermined speed or more. The required braking force shown in FIG. 3 is mapped to a graph representing the required acceleration with the vertical axis representing the vehicle traveling direction as a positive direction, and a negative direction is a direction in which the required braking force is increased. The example shown in FIG. 3 represents that the estimated required braking force increases from the time when the accelerator opening becomes 0%.

  Further, as shown in FIG. 3, the engine speed gradually decreases in response to the accelerator opening being 0% and converges to a constant value.

  (Step S103): The line pressure setting unit 13 compares the magnitude of the required braking force with a predetermined positive threshold. If the required braking force is smaller than the threshold value, the process proceeds to step S104, and if the required braking force is greater than or equal to the threshold value, the process proceeds to step S105.

  (Step S104): The line pressure setting unit 13 sets the line pressure of the automatic transmission 300 to the first set value. The line pressure is a hydraulic pressure of hydraulic oil provided to an engagement friction element such as a clutch or a brake in the automatic transmission 300. Generally, a higher line pressure is required at higher vehicle speeds and higher torques. However, if the line pressure is increased, the engine load and the torque loss in the automatic transmission 300 increase, so that the braking force during coasting operation increases. In this step, the line pressure setting unit 13 sets the line pressure as the first set value, which is sufficient for the operation of the automatic transmission 300 and can realize low fuel consumption, for example, according to the engine speed or the like. Set as appropriate. The first set value may be a fixed value or a variable value. After this step, the process proceeds to step S106.

  (Step S105): When the required braking force is greater than or equal to the threshold, the line pressure setting unit 13 sets the line pressure to a second set value that is higher than the first set value in accordance with the required brake force. In FIG. 3, as an example of the second set value, a case where the line pressure is set to a constant value higher than the first set value is indicated by a solid line. For comparison, an example in which normal control for decreasing the line pressure in accordance with a decrease in the engine speed is shown by a dotted line. The line pressure indicated by the dotted line gradually decreases as the engine speed decreases and converges to a constant value.

  (Step S106): The line pressure setting unit 13 controls the automatic transmission 300 based on the set line pressure. In FIG. 3, the actual output torque when the line pressure is set to the second set value according to the required braking force is indicated by a solid line. For comparison, the actual output torque when the line pressure indicated by the dotted line is set is indicated by a dotted line. Moreover, the actual output torque corresponding to the above-mentioned required braking force is indicated by a one-dot chain line. The actual output torque shown in FIG. 3 is mapped to a graph that represents acceleration with the vertical axis representing the vehicle traveling direction as a positive direction, and a negative direction is a direction in which the actual output torque becomes smaller. Power is generated. In the example shown in FIG. 3, when the line pressure is set high, the actual output torque sharply decreases to 0 G or less, and braking force control close to the user's requested braking force is possible. This control ends when, for example, the user performs an accelerator operation or a brake operation, or when a predetermined condition such as the vehicle speed is reduced to a predetermined speed is satisfied. When the establishment of the coasting state is detected again, the processing from step S101 is executed again.

  The above processing may be implemented with appropriate changes. For example, the braking force control apparatus 100 is configured not only to control the line pressure of the automatic transmission 300 but also to control an engine, an air conditioner, a brake, an alternator, and the like mounted on the vehicle. The braking force may be generated by combining the output, the shift of the automatic transmission 300, the use of an air conditioner, a brake, an alternator, and the like. Further, the line pressure setting unit 13 may perform feedback control in which a difference between the required braking force and the actually obtained braking force is acquired and the set value of the line pressure is corrected based on the difference. Further, the line pressure setting unit 13 can detect that an abnormality has occurred in the automatic transmission 300, and control the line pressure to be maximum when the abnormality occurs so that the braking force is increased. Good.

<Effect>
According to the present invention, the required braking force from the user at the time when the coasting state is established is estimated, and when the estimated required braking force is greater than the threshold, the line pressure of the automatic transmission is increased as compared with the case where the estimated required braking force is not greater. To generate a braking force. Thereby, it is possible to suitably obtain the braking force requested by the user.

  Note that the present invention can be understood not only as a braking force control device for a vehicle but also as a method executed by a computer of the braking force control device, a program or a control system including the braking force control device, and a vehicle.

  The present invention is useful for a vehicle equipped with a transmission or the like.

11 coasting state detection unit 12 braking force estimation unit 13 line pressure setting unit 100 braking force control device 200 sensor group 300 automatic transmission

Claims (1)

A braking force control device for a vehicle,
A coasting state detection unit that detects that a coasting state in which the accelerator operation is not performed and the brake operation is not performed is established while the vehicle is traveling,
When the coasting state detection unit detects that the coasting state is established, a braking force estimation unit that estimates a requested braking force that is a braking force requested by a user;
If the required braking force estimated by the braking force estimation unit is greater than or equal to a predetermined threshold, the line pressure of the automatic transmission of the vehicle is set to a higher value than when the required braking force is less than the threshold, A braking force control device comprising: a line pressure setting unit that generates a braking force of a vehicle.

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