Abstract: An apparatus for estimating a road traffic condition and for controlling a vehicle running characteristic includes a controller having a fuzzy inference function and a neural network function. The controller carries out frequency analysis on vehicle driving parameters such as vehicle speed, steering angle, accelerator opening degree, and longitudinal acceleration and lateral acceleration of a vehicle, to thereby determine a mean value and variance of each parameter. It implements fuzzy inference based on a traveling time ratio, an average speed, and an average lateral acceleration, which are obtained from vehicle speed and/or steering angle, to thereby calculate road traffic condition parameters, including a city area degree, a jammed road degree, and a mountainous road degree.

Abstract: An apparatus for estimating a vehicle maneuvering state and controlling a vehicle running characteristic includes a controller having a fuzzy estimating function and a neural network function. The controller carries out frequency analysis on vehicle driving parameters such as vehicle speed, steering angle, opening degree of an accelerator, and longitudinal acceleration and lateral acceleration of a vehicle, to thereby determine a mean value and variance of each parameter. It implements fuzzy inference based on a traveling time ratio, an average speed, and an average lateral acceleration, which are obtained from vehicle speed and/or steering angle, to thereby calculate road traffic condition parameters, including a city area degree, a jammed road degree, and a mountainous road degree.

Abstract: A control method and an apparatus therefor, in which the braking force distribution to rear wheels is increased in a normal state, while the braking force distribution to the rear wheels is reduced to prevent the rear wheels from being locked in an early stage when the road surface is slippery. There are provided a pressure sensor (74) for detecting a master cylinder pressure, proportioning valves (57.sub.1, 57.sub.2) arranged in passages which connect a master cylinder and rear wheel cylinders and adapted to operate so that the ratios of the wheel cylinder pressures to the master cylinder pressure are low in a region where the master cylinder pressure is not lower than a predetermined pressure, normally-open switching valves (62, 63) by-passing the two valves, and a controller (71).

Abstract: A pneumatic active suspension apparatus is provided wherein, when a sprung vertical acceleration (ZG), which causes a wafting phenomenon perceptible by a person in a vehicle, occurs during travel of the vehicle, supply/discharge of air to/from air spring chambers of suspension units is carried out for a supply/discharge control time determined based on the maximum value (ZGmax) of the sprung vertical acceleration. The supply/discharge control is started at an advanced time based on the sprung acceleration whose phase is advanced by 90 degrees from that of the sprung velocity, to thereby produce a force acting to cancel out the sprung vertical velocity at proper timing. As a result, the operation delay of the suspension apparatus is compensated for and the sprung vertical motion is suppressed.

Abstract: A rear wheel braking force control apparatus of a vehicle includes a pressure sensor 74 for detecting master cylinder pressure, right and left proportioning valves 57.sub.1 and 57.sub.2 individually disposed in passages for transmitting master cylinder pressure to right and left wheel cylinders of the rear wheels for controlling to decrease changes in wheel cylinder pressure relative to changes in master cylinder pressure, right and left PCV bypass valves 62 and 63 for individually bypassing the proportioning valves, and a controller 71 which, when the vehicle is determined by a steering angle sensor 77 or the like to be turning, closes the PCV bypass valve at the outer wheel side when the master cylinder pressure is higher than the pressure of the PCV bypass valve at the inner wheel side.

Abstract: When a master cylinder pressure detected by way of a pressure sensor (74) attains a level not lower than a target pressure (P.sub.OK), normally-open on-off valves (62, 63) for by-passing proportioning control valves (57.sub.1, 57.sub.2) are opened. If the slip factor of rear wheels, calculated by way of a slip factor calculation section (121), is not lower than a predetermined value, the on-off valves (64, 66) are opened to allow the rear wheel cylinder pressure to escape to accumulators (65, 67). Thus, if there is enough room for the increase of the braking force on the rear wheels, the rear wheel braking force can be increased to reduce the share of the front wheel braking force, depending on braking conditions, such as the road surface conditions, vehicle running conditions, etc. Further the rear wheels can be prevented from being locked.

Abstract: In a turning control apparatus for a vehicle, a torque calculation unit calculates a target lateral acceleration of the vehicle according to detection signals from a steering angle sensor for detecting the direction of a steering wheel and a vehicle speed sensor for detecting the speed of the vehicle. It then sets target driving torque of the engine according to the target lateral acceleration. An electronic control unit controls the operation of a torque control device for reducing driving of the engine so that the driving torque of the engine is a target driving torque independent of manipulation by the driver. This thereby rapidly estimates lateral acceleration applied to the vehicle during turning and prevents control delay to enable stable and positive traveling through a curved road.

Abstract: A motor vehicle output power control system quickly reduces the drive torque produced by an engine on a motor vehicle depending on the magnitude of a lateral acceleration which is produced when the motor vehicle makes a turn, or the amount by which drive wheels slips when the motor vehicle is accelerated. A target drive torque depending on the lateral acceleration and a demanded drive torque demanded by the driver of the motor vehicle are added at a predetermined ratio into a turn target drive torque, which is selected as a final target drive torque. The motor vehicle output power control system includes an electronic control unit for controlling an actuator to lower the output drive torque of the engine, independent from controlling action of the driver, such that the output drive torque of the engine is equalized to the final target drive torque.

Abstract: A four-wheel steering apparatus for a vehicle includes a hydraulic actuator for steering the rear wheels, and first and second oil pumps. An in-phase steering control valve is connected between the first oil pump and the actuator and outputs first hydraulic output for steering the rear wheels in phase with the front wheels in accordance with a steering state of the front wheels. An antiphase steering control valve is connected between the second oil pump and the actuator and outputs second hydraulic output for steering the rear wheels in opposite phase to the front wheels in accordance with a rate of change in the steering state of the front wheels. The hydraulic actuator combines the first and second hydraulic outputs from the control valves and steers the rear wheels in accordance with the difference between the hydraulic outputs.

Abstract: A rear wheel suspension arrangement of trailing arm type for motor vehicles includes a trailing arm for supporting a rear wheel, and a pair of upper and lower lateral arms. The trailing arm is split into a vehicle body side arm and a wheel side arm, which are coupled to have a degree of displacing freedoms within a horizontal plane of the vehicle body. The vehicle body side arm is formed shorter than the lateral arms, whose pivotally securing portion to the vehicle body is disposed at the front side from the coupling portion to the wheel side arm, and disposed in the inside in the lateral direction from the wheel side arm. The lower lateral arm is pivotally secured at least to the wheel side arm via a ball joint.

Abstract: A rear wheel steering system of the trailing arm type suspension for rear wheels having a trailing arm for supporting at the rear portion thereof a rear wheel and extending essentially in the longitudinal direction of a vehicle body by pivotally securing the front end thereof to the body side. Lateral arms are rotatably coupled at the outer ends thereof to the rear portion of the trailing arm and extending essentially in the lateral direction of the vehicle by pivotally securing the inner ends thereof to the vehicle body. The trailing arm allows the front portion thereof to displace essentially in the lateral direction of the vehicle. The rear wheel suspension arrangement allows the trailing arm to displace substantially in the lateral direction of the front end thereof and which comprises an actuator for steering a rear wheel by operating the trailing arm to displace the front portion of the trailing arm essentially in the lateral direction of the vehicle.

Abstract: A brake system for a vehicle comprises a booster unit including a power piston disposed slidably in a housing for defining a first chamber and a second chamber in the housing, a regulator disposed slidably in the power piston, a flow restrictor formed between the first chamber and a fluid pressure source for restricting flow of fluid in response to movement of the regulator, a pilot pressure chamber disposed upstream of the flow restrictor, a movable member moved by the internal pressure of the pilot pressure chamber thereby permitting communication between the second chamber and the fluid pressure source, and a reaction spring disposed between the power piston and the regulator. A master cylinder is connected to the power piston of the booster unit to supply braking hydraulic fluid at controlled pressure to front and rear brakes, and a brake pedal actuates the regulator of the booster unit to cause movement of the regulator relative to the power piston.

Abstract: A brake system for a vehicle comprises a booster unit including a piston disposed for sliding movement in a cylinder, a pressure chamber defined between the cylinder and the piston, and a valve member arranged for interlocking movement with the brake pedal and disposed slidably in the piston for controlling flow of hydraulic fluid from a fluid pressure source into the pressure chamber. A pressure control valve is disposed between the fluid pressure source and the booster unit for controlling the maximum internal pressure of the pressure chamber of the booster unit depending on the weight of the vehicle sensed by a sensor, and a master cylinder is connected to the piston of the booster unit to supply braking hydraulic fluid at controlled pressure to the front and rear brakes.