Akebono Brake Industry Co., Ltd.

Akebono Research and Developement Centre Ltd.

Akebono Brake Co., Ltd.

Akebono Brake Industry

Satomi Okubo

Toshifumi Maehara

An anti-lock control method whereby a control period of pressurization/pressure-reduction during anti-lock control is maintained constant. In the anti-lock control method, a control period T(n) from a high peak of a body velocity to a next high peak is measured, a difference between a target control period time (Tset) and the control period time T(n) is obtained when the control period time is shorter than the target control period time (Tset), the difference is added to a current pressurization start delay time Twait(n-1) to obtain a next pressurization start delay time Twait(n), and a next pressurization start time is delayed by the obtained pressurization start delay time.

Anti-lock control method and apparatus

When, after a yawing moment control starts in an anti-lock braking system the rear wheel on the low-.mu. road surface is locked and the speed of that wheel decreases below the threshold value VT1, the brake hydraulic pressure to the wheel on the low-.mu. road surface is decreased. At the same time, the brake hydraulic pressure to the rear wheel on the high-.mu. road surface is also decreased at reduced rate relative to the decrease on the low-.mu. wheel. As a result, a higher braking force acts on the wheel on the high-.mu. road surface than on the wheel on the low-.mu. road surface. When the speed of the wheel on the low-.mu. road surface decreases below the threshold value VT1 and when the speed of the wheel on the high-.mu. road surface decreases below the pressure-decrease restriction removal threshold value VT, the brake hydraulic pressure to the wheel on the high-.mu. road surface is decreased to be nearly equal to that to the wheel on the low-.mu. road surface to prevent the wheels on the high and .mu. road surfaces from being locked.

Method for controlling the braking pressure applied in an anti-lock

In an anti-lock control arrangement for preventing locking of vehicle wheels, a prescribed speed difference of a threshold speed from an estimated vehicle speed is changed from an initial value of the difference to a larger value when a wheel speed has been lower for a prescribed time than the threshold speed which follows the estimated vehicle speed with the prescribed speed difference therefrom or when a prescribed statement with respect to the wheel speed is repeated at a predetermined number. Further, the speed difference of the threshold speed from the estimated vehicle speed is changed back to the initial value when the wheel speed has become lower than the threshold speed subjected to the former change.

Anti-lock control method and apparatus for automotive vehicle

An anti-lock control system in which a pressure increasing cycle changes according to the behavior of a wheel during a pressure increasing mode of anti-lock control. The anti-lock control system determines a coefficient of friction of a road surface, sets a maximum vehicle body deceleration according to the coefficient of friction, calculates the deceleration of the wheel speed to be controlled, compares the deceleration of the wheel speed to be controlled with the maximum vehicle body deceleration Gmax to determine whether or not to increase or maintain constant the brake fluid pressure.

Anti-lock control system for motor vehicles

An anti-lock braking control method for a vehicle for preventing locking of vehicle wheels, wherein brake hydraulic pressure is controlled in accordance with a wheel speed to be controlled in each brake control system or channel. The increase in the brake hydraulic pressure in one of the brake control channels is started when a predetermined condition is determined to be met in that control channel and after the predetermined condition is also determined to by met in another control channel. The predetermined condition is determined to be met for a control channel when the system speed Vs for that control channel becomes higher than a speed Vv-.DELTA.Vo, which corresponds to the estimated vehicle speed Vv lowered by a predetermined minute value .DELTA.Vo.

Anti-lock braking control method and apparatus for a vehicle

An anti-lock control arrangement for preventing locking of vehicle wheels by increasing, holding constant and decreasing brake hydraulic pressure through a plurality of control channels on the basis of system speeds Vs, an estimated vehicle speed Vv, a target speed VT and accelerations and decelerations dVs/dt of the vehicle wheels. With respect to one of the control channels, the target speed VT is modified when there is a speed difference .DELTA.V between corresponding one of said system speeds Vs and the highest wheel speed VwH at the time of start of braking. The modified target speed is defined by a speed lowered by the speed difference .DELTA.V than said target speed VT.

An anti-lock control method for preventing a vehicle from yawing during braking, while driving on a split road surface. The amounts of the pressure increase in a right wheel and a left wheel control system, controlled independently of each other, are compared with each other. When there is a difference between the two pressure increase amounts, it is determined that the control system having the greater pressure increase amount is the high road-side control system whereas the other control system, having the smaller pressure increase amount, is the low road-side control system. The brake hydraulic pressure in the high road-side control system is controlled so that it does not excessively increase.

Anti-lock control method for preventing vehicle yawing

An anti-lock control arrangement for a vehicle which employs a control map for effectively preventing a wheel lock during braking. The control map is defined in terms of acceleration-deceleration values of a vehicle speed, which is to be controlled, and a speed difference between a target speed and a vehicle speed. The control map is read during anti-lock operation to effectuate control of the brake hydraulic pressure.

Braking anti-lock control for vehicle

In a three-channel anti-lock control apparatus in which brake hydraulic pressure for left and right rear wheels is controlled through a common control channel based on a lower wheel speed selected from left and right rear wheel speeds, a pressure increase rate only for one of the right and left wheels, which one has a higher speed than the other, is increased in a case where a speed difference between left and right rear wheel speeds is not less than a predetermined value .DELTA.V and the common control channel is not in a pressure decrease status.

Anti-lock control apparatus for automotive vehicles

An anti-lock control method and apparatus is charecterized in that if the highest one VwH of the speeds of the four wheels of the vehicle is still lower than a prescribed threshold speed and not increasing at a second time point at which a prescribed time .DELTA.T has elapsed after a first time point at which the highest wheel speed becomes lower than the threshold speed, the estimated vehicle speed is modified to be equal to the highest wheel speed VwH, thereby preventing an automotive vehicle from being not braked at the start of anti-lock control immediately after an estimated vehicle speed has changed away from the actual vehicle speed as the wheel of the vehicle performs an acceleration slip before the start of the anti-lock control.

Anti-lock control method for automotive vehicles

An anti-lock control apparatus and method in which the brake hydraulic pressure is controlled by regarding an estimated vehicle speed as an actual vehicle speed, is characterized in that the estimated vehicle speed is corrected when the estimated vehicle speed is extremely reduced relative to the actual vehicle speed when the four wheel speeds are reduced at the same time, or the like, thereby preventing the estimated vehicle speed from being away from the actual speed. It can be applied as the correction of the estimated vehicle speed that the estimated vehicle speed may be maintained at a constant value, and the deceleration and acceleration of the estimated vehicle speed may be varied in accordance with a friction coefficient of the road surface.

Vehicle anti-lock control apparatus and method

In the vehicle using the three-channel anti-lock control method based on the front wheel independent-and-rear wheel select-low, only when the third system speed Vs3 to which the left and right rear wheels belong is subjected to the anti-lock control due to the abruptly decreasing of the third system speed before at least one of the left and right front wheel systems begin to be subjected to the anti-lock control, the decrease of the brake hydraulic pressure is not started even if the third system speed Vs3 becomes lower than the above threshold speed VT1 (Vs3&lt;VT1). In such case, only when the third system speed Vs3 becomes equal to or lower than the reference speed Vr (Vs3.ltoreq.Vr), the decrease of the hydraulic pressure is started. By doing so, an excessive decrease of the brake hydraulic pressure in the third system at the time of the braking during the turning of the vehicle is prevented.

Vehicle anti-lock control method

In an anti-lock control system for a motor vehicle, the design is made such that when the motor vehicle is running on a rough road, it is detected that the motor vehicle is running on rough road, on the basis of which the amount of reduction of brake hydraulic pressure is restricted, thereby making it possible to shorten the braking distance of the motor vehicle.

A road surface friction coefficient estimating method and apparatus in an anti-lock control device for preventing locking of vehicle wheels during braking. The road surface friction coefficient is estimated by comparing a deceleration of an estimated vehicle speed with a predetermined threshold value. The predetermined threshold value has different road surface friction coefficient values corresponding to different vehicle deceleration values. The braking hydraulic pressure is then repeatedly varied in accordance with signals indicative of the estimated road surface friction coefficient, signals indicative of the estimated vehicle speed, and one of the signals indicative of the slowest rear wheel speed and the front wheel speeds.

Estimating road friction coefficient

An anti-lock control system is disclosed which includes rough-road judging means for judging whether the vehicle is running on a rough road or not; and decay timer means for limiting time period during which reduction of the brake hydraulic pressure is occurring. The decay timer means is arranged, when the vehicle is running on a normal road, to limit the time period of brake hydraulic pressure reduction within a first peredetermined time length, the decay timer means being also arranged to limit the time period of brake hydraulic pressure reduction within a second predetermined time length shorter than the first predetermined time length.

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Saitama, Japan

Satomi Okubo