Advics Co., Ltd.

Toyota Jidosha Kabushiki Kaisha

Akifumi Doura

Chiaki Hamada

Satoshi Udaka

Noritaka Yamada

Toshihisa Nihei

Masahiro Hara

Masahiro Matsuura

Hideyuki Aizawa

Hitoshi Terada

Yoshinori Suzuki

Yasuhisa Kuwahata

A braking force control device can control braking forces of the respective wheels of a vehicle, suppresses an increase of the braking force of a first wheel that is a wheel having a relatively large slip amount in a pair of right/left wheels and increases the braking force of a second wheel that is a wheel having a relatively small slip amount. The braking force control device may suppress the increase of the braking force of the first wheel before the friction coefficient of a road surface to the first wheel reaches a peak and when the friction coefficient is in the vicinity of the peak. It is preferable to suppress the increase of the braking force of the first wheel by holding the braking force of the first wheel.

Braking force control device

A vehicle braking control system includes a wheel cylinder which applies a braking force in accordance with a fluid pressure to a vehicle wheel and a control device which controls the fluid pressure of the wheel cylinder based on the vehicle wheel acceleration. Then, the control device applies the predetermined fluid pressure to the wheel cylinder so as to acquire a return level of the vehicle wheel acceleration and calculates a control target value of the fluid pressure based on a behavior of the vehicle wheel acceleration after starting a sudden braking operation and before starting ABS control.

Vehicle braking control system

A braking control device for a vehicle executes braking force distribution (BFD) biased to front wheel in a manner compatible with Anti-skid control. In BFD control, braking force on rear wheels is held at a holding braking force and braking force on the front wheels is incremented beyond braking force requested by a braking action of a driver. After the starting of BFD control, further increase in the braking action is reflected in the front wheel braking force. Upon starting anti-skid control for either of the wheels during the execution of BFD control, an increment of the front wheel braking forces to be requested by BFD control is gradually decreased. Simultaneously, the holding of the rear braking force is released so as to compensate for the shortage of braking force on the front wheel. The gradual decrease of the braking force increment prevents a conflict of BFD and Anti-skid control.

Vehicle braking control device for braking force distribution

A braking control device for a vehicle executes braking force distribution (BFD) biased to the front wheels, taking into account auxiliary braking control such as braking assist control (BAS) executed when an abrupt or full braking action is performed by the driver. In BFD control a braking force on the rear wheels is held at a holding braking force and a braking force on the front wheels is incremented beyond a braking force requested by a braking action of the driver. After the starting of BFD control, further increase in the braking action is reflected in the braking force of the front wheels. When auxiliary braking control is executed, the holding braking force on the rear wheels and the increment of the braking force on the front wheels are determined based upon a demand of the auxiliary braking action as well as the braking action amount by the driver.

The brake system of the invention, during the ABS control mode, corrects the target slip rate in accordance with the turning of the vehicle, and determines whether the vehicle is running on a poor surface road. If the vehicle is running on a poor surface road, the system sets a target slip rate that provides a greater longitudinal force than the aforementioned target slip rate.

Vehicular brake system and method of controlling same brake system

A braking control device of a vehicle starts executing braking force distribution (BFD) biased to front wheels for avoiding the locking of rear wheels prior to the front wheel at appropriate time by reducing errors of a judgment of the starting of the control. Usually, the BFD control is started in response to the increase of a master cylinder pressure, assuming that the rear wheel braking pressure is equally increased. When a fast braking action occurs, the delay of the pressure variation of the rear wheel braking pressure relative to the master cylinder is conspicuous because the responsibility of a master cylinder pressure to the braking action is too fast. Thus, Upon a fast braking action, a judgment of starting of BFD control is made based upon a value involved with rear wheel braking force, such as an estimation value of the rear wheel braking pressure, having a slower responsibility to the braking action than the master cylinder pressure, and thereby preventing a premature start of the BFD control due to the delay of the rear wheel braking pressure. When a deceleration signal is used for the judgment of starting of BFD control, the signal is passed through a low-pass filter having a rather higher cut-off frequency on a fast braking action, in order to improve the responsibility of the signal to the braking action.

If a condition for starting a yaw control during an antiskid control is met while the antiskid control is being executed on one of right and left front wheels during braking on a uneven friction-coeffient road surface, the reference value for making the determination to start the antiskid control on the other one of the front wheels is reduced, and therefore the antiskid control is started at an earlier timing. If the antiskid control is executed on the wheel, the brake pressure of the wheel is controlled in a pre-set specific pattern.

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Obu, Japan

Akifumi Doura