Vehicle brake hold system

Abstract

This invention provides a vehicle brake hold system that can prevent the vehicle from starting unintentionally by the driver. [Solution] The vehicle brake hold system 10 is a vehicle brake hold system 10 that maintains braking force even when the driver releases the brake operation after the driver has applied braking force to each wheel by operating the brakes, and when the mode of the vehicle's automatic transmission 14 is changed, the system increases the maintained braking force in accordance with the change in driving force due to the change in mode.

Description

Technical Field

[0001] The present disclosure relates to a vehicle brake hold system.

Background Art

[0002] A vehicle brake hold system is a system that holds braking force even when a driver releases a brake operation when the driver generates braking force on each wheel by a brake operation (for example, Patent Document 1). According to the vehicle brake hold system, it is possible to reduce the burden on the driver when repeatedly stopping and starting the vehicle.

[0003] In the vehicle brake hold system disclosed in Patent Document 1, when it is determined that an automatic transmission is set to a non-driving mode (for example, neutral mode), the braking force is increased. Thereby, even when the transmission is switched to the non-driving mode during the operation of the vehicle brake hold system, it is possible to reduce the discomfort felt by the driver.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the vehicle brake hold system disclosed in Patent Document 1, when the automatic transmission is set from a forward driving mode (for example, drive mode) to a reverse driving mode (for example, reverse mode) and the driving force changes, it is not possible to hold the stop. In this case, there is a risk that the vehicle may start without the driver's intention.

[0006] Therefore, the present invention aims to provide a vehicle brake hold system that can prevent the vehicle from starting unintentionally by the driver. [Means for solving the problem]

[0007] The vehicle brake hold system according to the present invention is a vehicle brake hold system that maintains braking force even when the driver releases the brake operation after generating braking force on each wheel by the driver of a vehicle, and is characterized in that when the mode of the vehicle's transmission is changed, the maintained braking force is increased in accordance with the change in driving force due to the change in mode. [Effects of the Invention]

[0008] According to the vehicle brake hold system of the present invention, it is possible to prevent the vehicle from starting unintentionally by the driver. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing a brake hold system, which is an example of an embodiment. [Figure 2] This is a schematic diagram illustrating the flow of brake hold control, which is one example of an embodiment. [Figure 3] This is a time-series diagram showing the flow of brake hold control, which is one example of an embodiment. [Modes for carrying out the invention]

[0010] An example of an embodiment of the present invention will be described in detail below. In the following description, specific shapes, materials, directions, numerical values, etc., are examples to facilitate understanding of the present invention and can be appropriately modified according to the application, purpose, specifications, etc.

[0011] [Brake Hold System] An example of an embodiment, the brake hold system 10, will be described using Figure 1.

[0012] The brake hold system 10 is a system that maintains braking force even after the driver releases the brakes when the driver has applied braking force to each wheel. According to the brake hold system 10, as will be described in more detail later, it is possible to prevent the vehicle from starting unintentionally.

[0013] The vehicle is, for example, a gasoline-powered automobile, which is driven by an engine as an internal combustion engine. Although the vehicle in this embodiment is a gasoline-powered automobile, the present invention is not limited to this. The vehicle of the present invention may be an electric vehicle (BEV (Battery Electric Vehicle)), a hybrid vehicle (HEV (Hybrid Electric Vehicle)), or a plug-in hybrid vehicle (PHEV (Plug-in Hybrid Electric Vehicle)).

[0014] The brake hold system 10 comprises, as will be described in detail later, a brake pedal (not shown), a brake actuator 12, a brake fluid pressure boosting actuator 13, an automatic transmission 14, a brake hold ECU (Electronic Control Unit) 50, a brake hold switch 51, a brake sensor 52, an accelerator pedal position sensor 53, a vehicle speed sensor 54, a transmission ECU 60, a shift lever 61, and a shift position sensor 62.

[0015] The brake pedal is the pedal used by the vehicle's driver to operate the brakes. Brake operation refers to the operation that activates the brake actuator 12, which will be described later.

[0016] The brake actuator 12 has the function of optimally distributing hydraulic pressure to brake components such as wheel cylinders of hydraulic drum brakes and calipers of hydraulic disc brakes, which are provided on four or two wheels, and comprises a hydraulic power source such as a hydraulic pump and an electromagnetic valve (not shown). With the brake actuator 12, the braking state of the wheels can be controlled.

[0017] Furthermore, the brake actuator 12 is equipped with a brake hold electromagnetic valve (not shown), which is a brake hold means for maintaining the braking force of the vehicle. By operating the brake hold electromagnetic valve, the brake fluid piping (not shown) is shut off, and the brake fluid is maintained at a constant pressure in the wheel cylinders or hydraulic cylinders in the calipers, which are provided for four or two wheels, for example, thereby maintaining the braking force, i.e., achieving a brake hold state. When the operation of the brake hold electromagnetic valve is stopped, the shutoff in the brake fluid piping is released, the connection between the wheel cylinders or hydraulic cylinders in the calipers and the oil tank is restored, and the braking force is released, i.e., the brake hold is released.

[0018] The brake fluid pressure boosting actuator 13 increases the braking force by further increasing the brake fluid pressure in the brake actuator 12, from a state where the brake fluid is held at a constant pressure in the wheel cylinder or hydraulic cylinder in the caliper. The configuration of the brake fluid pressure boosting actuator 13 is not particularly limited. The brake fluid pressure boosting actuator 13 may be a hydraulic circuit having an increasing electromagnetic valve, cylinder, and piping added to the brake actuator 12. The brake fluid pressure boosting actuator 13 may have a configuration similar to that of brake fluid increasing means used in, for example, an anti-skid device or a vehicle attitude stabilization device.

[0019] The automatic transmission 14 can be set to a mode in which the power output from the engine is transmitted to the drive wheels (drive mode, reverse mode, neutral mode, parking mode, etc.). These modes are selected using the shift lever 61, which will be described later.

[0020] The brake hold ECU controls the operations of the brake actuator 12 and the brake oil pressure boosting actuator 13. The brake hold ECU has a CPU (Central Processing Unit) as an arithmetic processing unit and a storage unit such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and performs signal processing according to a program stored in advance in the ROM while using the temporary storage function of the RAM.

[0021] The brake hold ECU is connected to a brake hold switch 51, a brake sensor 52, an accelerator opening sensor 53, and a vehicle speed sensor 54, receives detection signals from these sensors, and controls the brake actuator 12 and the brake oil pressure boosting actuator 13 according to the calculation results obtained from the detection signals.

[0022] When the brake hold switch 51, which will be described later, is turned ON by the driver, the brake hold ECU executes the brake hold function.

[0023] When the driver of the vehicle generates braking force on each wheel by operating the brake pedal with the brake actuator 12, if the brake hold conditions are satisfied, the brake hold ECU activates the electromagnetic valve for brake hold and maintains the braking force even when the driver releases the brake pedal. The brake hold conditions may be that the vehicle speed is lower than a preset predetermined speed, the ON state of the brake pedal continues for a predetermined time or more, and the accelerator opening condition for brake hold is smaller than a predetermined opening.

[0024] When the brake hold release conditions are satisfied, the brake hold ECU stops the operation of the electromagnetic valve for brake hold and releases the braking force. The brake hold release condition is to satisfy the accelerator opening condition for brake hold release, that is, the accelerator opening is larger than a predetermined opening.

[0025] The brake hold ECU, when the brake actuator 12 maintains a constant pressure of brake fluid in the wheel cylinder or hydraulic cylinder within the caliper, and the automatic transmission 14 is set from forward driving mode to reverse driving mode, further increases the brake fluid pressure using the brake fluid pressure boosting actuator 13 to increase the braking force. This allows the vehicle to maintain a stop even when the automatic transmission 14 is set from forward driving mode to reverse driving mode and the driving force changes. As a result, it is possible to prevent the vehicle from starting unintentionally by the driver.

[0026] The brake hold switch 51 is located around the driver's seat and is an on / off switch that allows you to select whether or not to activate the brake hold function according to the brake hold conditions described above.

[0027] The brake sensor 52 is a sensor that detects the on / off state of the brake pedal. The brake sensor 52 may also be a sensor that detects the stroke of the brake pedal, for example. The accelerator pedal position sensor 53 is a sensor that detects the accelerator pedal position corresponding to the amount of accelerator pedal operation. The vehicle speed sensor 54 is a sensor that detects the vehicle speed.

[0028] The transmission ECU 60 determines the gear position based on the shift position detected by the shift position sensor 62 (described later), accelerator pedal input, vehicle speed, etc., and controls the drive of the shift actuator (not shown) of the automatic transmission 14 based on the gear position. The transmission ECU 60 also transmits the current shift position to the brake hold ECU.

[0029] The transmission ECU 60 has a CPU, which is the processing unit, and memory units such as RAM and ROM. It performs signal processing according to a program pre-stored in ROM while utilizing the temporary storage function of RAM. The transmission ECU 60 is connected to the brake hold ECU 50.

[0030] The shift lever 61 is located around the driver's seat and is operated by the driver. The position of the shift lever 61 (shift position) is a mode of the automatic transmission 14 selected by the driver of the automatic transmission 14, and includes non-driving modes (e.g., parking mode, neutral mode), forward driving modes (e.g., drive mode), and reverse driving modes (e.g., reverse mode).

[0031] The shift position sensor 62 detects the position (shift position) of the shift lever 61 and outputs a signal representing the detected shift position.

[0032] [Brake hold control] Using Figures 2 and 3, we will explain the flow of brake hold control, which is an example of an embodiment.

[0033] As shown in Figure 2, brake hold control is performed by the following process by the CPU of the brake hold ECU 50. In step S11, the CPU checks whether the brake hold switch 51 is ON. If the answer in step S11 is YES, the process proceeds to step S12.

[0034] In step S12, the CPU checks whether the driver has applied the brakes using the brake pedal. If the answer in step S12 is YES, the process proceeds to step S13. In step S13, the CPU maintains the braking force even if the driver releases the brake pedal.

[0035] In step S14, the CPU checks whether the current driving mode has changed from forward driving mode (e.g., drive mode) to reverse driving mode (e.g., reverse mode). If the answer in step S14 is YES, the process proceeds to step S15.

[0036] In step S15, the CPU increases the braking force by increasing the pressure in the wheel cylinder or the hydraulic cylinder in the caliper. This allows the vehicle to maintain a stop even when the automatic transmission 14 is set from a forward driving mode (e.g., drive mode) to a reverse driving mode (e.g., reverse mode) and the driving force changes, as described above. As a result, it is possible to prevent the vehicle from starting unintentionally by the driver.

[0037] As shown in Figure 3, the brake hold system 10 has a brake hold function that maintains braking force even after the driver releases the brake pedal when the driver applies braking force to each wheel by operating the brake pedal.

[0038] Suppose that while the brake hold function of the brake hold system 10 is activated, the driving mode is changed from a forward driving mode (e.g., drive mode) to a reverse driving mode (e.g., reverse mode) by the driver's operation of the shift lever 61. In this case, the actual driving force increases as the drive gear ratio in the automatic transmission 14 increases.

[0039] In the brake hold control of this embodiment, if the driving mode is changed from forward driving mode to reverse driving mode while the brake hold function is activated, the brake fluid pressure boosting actuator 13 increases the pressure of the wheel cylinder or the hydraulic cylinder in the caliper to increase the braking force.

[0040] This allows the automatic transmission 14 to maintain braking force even when the driving force changes, such as when it switches from forward driving mode to reverse driving mode. As a result, it is possible to prevent the vehicle from starting unintentionally by the driver.

[0041] It should be noted that the present invention is not limited to the embodiments and their modifications described above, and various changes and improvements are possible within the scope of the claims of this application. [Explanation of symbols]

[0042] 10 Brake hold system, 12 Brake actuator, 13 Brake fluid pressure boosting actuator, 14 Automatic transmission, 50 Brake hold ECU, 51 Brake hold switch, 52 Brake sensor, 53 Accelerator position sensor, 54 Vehicle speed sensor, 60 Transmission ECU, 61 Shift lever, 62 Shift position sensor

Claims

[Claim 1] A vehicle brake hold system that maintains the braking force applied to each wheel by the driver of a vehicle when the driver releases the brake operation, When the transmission mode of the vehicle is changed, the braking force being held is increased in accordance with the change in driving force resulting from the change in mode. Vehicle brake hold system.

Images