Unisia Jecs Corporation

Hitachi, Ltd.

Hitachi Unisia Automotive, Ltd.

Gen Inoue

Nobuyuki Ohtsu

Atsushi Ishikawa

Chiharu Nakazawa

Sunao Hano

Yukihiko Inoue

Masamichi Imamura

Tamotsu Yamaura

An antiskid control system for a four-wheel-drive vehicle is arranged to calculate a difference between an average of wheel accelerations of front wheels and an average of wheel acceleration of rear wheels. When the difference is greater than or equal to the vibration determination threshold, the antiskid control system determines that a driveline vibration is generated and executes a control for converging the driveline vibration.

Antiskid control system for four-wheel-drive vehicle

A vehicle brake control system includes an electric fluid pump that, upon energization thereof, pumps brake fluid from a reservoir to a brake circuit at a position upstream of a pressure control valve, an inlet circuit connecting the inlet opening of the pump to a master cylinder, an inside gate valve installed in the inlet circuit, and a control unit that controls the pressure control valve, the inlet gate valve and the electric fluid pump and carries out a predetermined brake control to adjust the hydraulic pressure of the wheel cylinder by operating the pressure control valve. The control unit is configured to carry out a flow back control after completion of the predetermined brake control. The flow back control is a control wherein the inside gate valve is kept open having the electric fluid pump kept de-energized.

Vehicle brake control system

In anti-skid control system and method for an automotive vehicle, when a calculated wheel deceleration of any one of road wheels of the vehicle has reached to a predetermined deceleration set on the basis of a pseudo vehicle body deceleration calculated from detected road wheel velocities, an electronic control unit (ECU) suspends a pressure increase control such as to increase a brake liquid pressure of the road wheel corresponding one of wheel cylinders and executes such a pressure hold control as to hold the brake liquid pressure thereof.

Anti-skid control system and method for automotive vehicle

A brake control system includes an ECU having an estimate part which is so constructed as to: totalize an influent amount of fluid in a brake actuator in accordance with an output time of a valve opening drive signal of a control signal and a supply amount per unit time of fluid in a pressure control valve; estimate an amount of fluid in the brake actuator in accordance with the influent amount as totalized; estimate a value of the fluid pressure within the brake actuator in accordance with the amount of fluid as estimated; and carry out correction for obtaining a supply amount of fluid in the brake actuator when a time of retaining operation performed by the control signal is smaller than a predetermined value, correction being performed by adding a correction value corresponding to the time to the output time of the valve opening drive signal of the control signal.

System for estimating brake-fluid pressure

In an antiskid brake control system, an ECU estimates a wheel slip in accordance with a sensed wheel speed and controls a fluid pressure control valve for braking operation in accordance with the estimated wheel slip for an antiskid brake control, the fluid pressure being reduced when the wheel slip is enlarged and being increased when the wheel slip is lowered. When a vehicle-body speed is smaller than a predetermined quick pressure reduction prohibiting speed, the ECU performs a quick pressure reduction prohibiting control to restrain a quick pressure reduction having a greater reduction amount than a predetermined reduction amount.

Antiskid brake control system

In an antiskid brake control system, an ECU is constructed to calculate a pseudo vehicle-body speed in accordance with a sensed wheel speed, calculate a target wheel speed in view of a predetermined slip ratio obtained in accordance with a calculated pseudo vehicle-body speed, carry out pressure reducing control by reducing the fluid pressure within a hydraulic unit when the sensed wheel speed is smaller than the calculated target wheel speed, estimate an amount of fluid stored in a reservoir, and correct the target wheel speed to lessen the slip ratio when the estimated fluid amount is greater than a predetermined value.

An automotive brake control system with an anti-brake skid (ABS) unit which controls a wheel-brake cylinder pressure to each individual wheel cylinder of the road wheels to prevent a wheel lock-up condition during braking, and an ABS control unit being configured to be connected electrically to at least wheel speed sensors and the ABS unit to execute skid control having at least a reduce-pressure operating mode and a pressure build-up operating mode, when the wheel speed sensor signals indicate that at least one of the road wheels is locking up. The ABS control unit includes a road-surface-condition change determination section which determines, based on both a time length of brake-fluid-pressure control continuously executed during the skid control and a recovery acceleration of the wheel speed of the road wheel subjected to the skid control, whether there is a road-surface &mgr; change from low-&mgr; road to high-&mgr; road.

Growing community of inventors

Kanagawa, Japan

Gen Inoue