Hitachi Automotive Systems, Ltd.

Nissan Motor Company Limited

Toshiya Oosawa

Asahi Watanabe

Hiroki Sonoda

Makoto Yamakado

Akira Takahashi

Junya Takahashi

Ryohei Maruo

Ryo Ota

Yuki Nakada

Atsushi Yokoyama

Chiharu Nakazawa

Jun Kubo

Naganori Koshimizu

Shinjiro Saito

Takuya Murakami

Akihiro Asai

Yuki Akiyama

Masayuki Saito

Hiroshi Owada

Hideaki Yagashira

Provided is a master cylinder unit including a simulator pressure chamber which communicates with a pressure chamber of a master cylinder and moves a simulator piston by means of an introduced fluid pressure; a biasing chamber in which a biasing mechanism biasing the simulator piston against a fluid pressure introduced into the simulator pressure chamber is disposed; a first seal member which partitions a simulator supply chamber, the simulator supply chamber, and the simulator pressure chamber communicating with a master supply chamber; and a second seal member which partitions the simulator supply chamber and the biasing chamber and allows a brake fluid to flow from the simulator supply chamber to the biasing chamber when a pressure difference occurs between the simulator supply chamber and the biasing chamber.

Master cylinder unit

A system comprises: pump (hydraulic pressure source) that uses brake fluid supplied from reservoir tank (reservoir) to generate hydraulic pressure in first hydraulic line, thereby generating hydraulic pressure in wheel cylinder; piston configured to move axially in cylinder under the action of hydraulic fluid supplied from master cylinder, piston dividing cylinder into at least two chambers (positive pressure chamber and backpressure chamber); stroke simulator for generating reaction force to a driver's brake operation by moving piston; second hydraulic line provided between positive pressure chamber in stroke simulator and master cylinder; and third hydraulic chamber provided between backpressure chamber and first hydraulic chamber to transmit brake fluid from backpressure chamber to first hydraulic chamber.

Brake control system, brake system, and brake hydraulic pressure generating method

An object of the present invention is to provide a brake apparatus capable of acquiring a stable brake performance. A brake apparatus includes a master cylinder configured to be activated according to a brake operation performed by a driver, a reservoir tank divided into at least a first chamber connected to a wheel cylinder via the master cylinder and a second chamber connected to a hydraulic source configured to increase a pressure of brake fluid and transmit the brake fluid to the wheel cylinder, a brake control unit configured to perform brake control of transmitting the brake fluid to the wheel cylinder, and a fluid level detection unit configured to detect a fluid level of the brake fluid in the reservoir tank. The brake control unit is provided so as to be able to perform first brake control of transmitting the brake fluid from the first chamber to the wheel cylinder with use of the master cylinder, thereby increasing a pressure in this wheel cylinder, and second brake control of transmitting the brake fluid in the second chamber to the wheel cylinder with use of the hydraulic source, thereby increasing a pressure in this wheel cylinder. The brake control unit switches brake control between the first brake control and the second brake control according to the fluid level detected by the fluid level detection unit.

Brake apparatus

A brake apparatus activates a stroke simulator OUT valve in a valve-closing direction to increase a pressure in a wheel cylinder with use of brake fluid flowing out of the stroke simulator according to a state of an operation performed by a driver on a brake pedal. Further, when the hydraulic pressure in the wheel cylinder or a first oil passage is brought into a predetermined state, the brake apparatus activates the stroke simulator OUT valve in a valve-opening direction to cause the brake fluid in the stroke simulator to flow out to a low-pressure portion while restricting the brake fluid in the stroke simulator to a predetermined flow amount.

In a system including a reservoir tank RSV integral with a master cylinder M/C, an inlet fluid passagefor connecting an inlet portionof a pump P to the reservoir tank RSV, a pressure reducing fluid passagethat connects the inlet fluid passageto wheel cylinders W/C and a normally closed pressure reducing valethat is connected to the pressure reducing fluid passageand opened when it is intended to depressurize a brake fluid to in the wheel cylinders thereby to return the brake fluid to the reservoir tank through the inlet fluid passage, there is employed a normally closed reservoir shutting valvethat is connected to the pressure reducing valvein series with respect to the wheel cylinders W/C and the reservoir tank RSV.

In a vehicle control device, a slip ratio in which front and rear wheels are averaged, and a braking force in which the front and rear wheels are averaged, can be calculated. The vehicle control device is provided with: friction braking devices placed on each wheel; a motor that acts as a regenerative braking mechanism and is placed on the rear wheels; a vehicle slip stiffness calculation unit; a front and rear braking force ratio calculation unit; a vehicle slip stiffness correction unit; and a regenerative braking arithmetic unit. The regenerative braking arithmetic unit operates the friction braking device and the motor so as to make the vehicle slip stiffness reach a vehicle slip stiffness threshold value. Also, the vehicle slip stiffness correction unit corrects the vehicle slip stiffness threshold value in accordance with the ratio of the front wheel braking force and the rear wheel braking force.

Vehicle control device

The present invention provides a brake device that can improve the pressure-increasing response of wheel cylinder hydraulic pressure. The invention is provided with: a master cylinder () actuated by the driver operating the brake, the master cylinder () being connected to a wheel cylinder () via a first oil channel (), and capable of increasing the wheel cylinder hydraulic pressure; and an auxiliary pressure-increasing part (auxiliary pressure-increasing part () and stroke simulator ()) for assisting in the increasing of the wheel cylinder hydraulic pressure by the master cylinder () of the pump ().

Brake device

There is provided a brake apparatus configured to identify a fluid leak spot while generating a braking force. The brake apparatus is configured to drive pumpto supply a brake fluid to a first fluid passage (fluid passageP, discharge passageP) and a second fluid passage (fluid passageS, discharge passageS), switch communicating valvesP andS alternately between open and closed positions more than once, and detect a brake-fluid leakage in the first or second fluid passage on the basis of magnitudes of detection values detected by hydraulic-pressure sensorsP andS during the open-close switching.

A parking assist device includes a target steering angle setting section configured to set a target value of the steering angle; a target vehicle speed setting section configured to set a target value of the vehicle speed; an automatic steering control device configured to automatically steer the steering wheel so that the sensed steering angle becomes the target steering angle; an automatic vehicle speed control device configured to automatically control the vehicle speed so that the sensed vehicle speed becomes the target vehicle speed; and a parking space recognizing section configured to recognize a parking space of the host vehicle, the host vehicle being parked within the recognized parking space by the automatic steering control device and the automatic vehicle speed device.

Parking assistance device and parking assistance device control method

Vehicular motion control system comprising controller that independently controls driving force and/or braking force of each of four wheels and a turning direction sensor that senses a turning direction, and with an acceleration/deceleration command generator that generates an acceleration/deceleration command based upon a sensed steering angle and sensed vehicle speed and a driving force/braking force distributor that determines the distribution of driving force or driving torque and/or braking force or braking torque of each wheel, and driving force/braking force distributor determines based upon the acceleration/deceleration command and the turning direction so that more driving force or more driving torque and/or more braking force or more braking torque are/is distributed to the inside front wheel in turning than the outside front wheel in turning and more driving force or more driving torque and/or more braking force or more braking torque are/is distributed to the outside rear wheel.

Motion control system of vehicle

A running-environment recognition apparatus includes an information recognition section mounted in a vehicle and configured to recognize an information of at least a frontward region of the vehicle relative to a traveling direction of the vehicle; and a road-surface calculating section configured to calculate a road surface of a traveling road and a portion lower than the road surface in the frontward region of the vehicle, from the information recognized by the information recognition section.

Running-environment recognition apparatus

In vehicular control apparatus and method, a traveling environment of a forward position of an advance direction of a vehicle in which an actuator for a vehicular control purpose is mounted is detected, a reliability of a result of measurement of the traveling environment by the traveling environment measurement section is determined, and an operation of the actuator is determined with the determined reliability as a requiring condition.

Vehicular control apparatus and method

In a vehicle control apparatus employing a first speed self-adjustment control system configured to control a speed of a host vehicle based on a first command value, in a manner so as to maintain a distance of the host vehicle from a preceding vehicle or to maintain a set speed, a second speed self-adjustment control system is provided for controlling the host vehicle's speed based on a second command value determined based on information about a lateral acceleration acting on the host vehicle. Also provided is a deceleration selector configured to select either one of the first and second command values, which selected command value produces a greater deceleration exerted on the host vehicle. A control unit is configured to control the host vehicle's speed by driving an actuator based on the selected command value.

Vehicle control apparatus

A vehicle control apparatus includes a first section that recognizes a lane boundary line of a lane in which a vehicle is traveling. A second section recognizes a present position of a predetermined reference point of the vehicle. A third section calculates a predicted position of the reference point, wherein the predicted position is a predetermined interval ahead of the present position. A fourth calculates an imaginary lane boundary line, wherein the imaginary lane boundary line is tangent to the lane boundary line at a point close to the predicted position. A fifth section performs a control of preventing the vehicle from deviating from the lane by controlling the vehicle depending on positional relationship between the vehicle and the lane boundary line. A sixth section selectively permits and suppresses the control depending on positional relationship among the imaginary lane boundary line, the present position, and the predicted position.

Vehicle control apparatus and vehicle control method

There is provided a vehicle motion control system which carries out acceleration and deceleration of a vehicle which satisfies driving feeling of a driver even in the state where a lateral motion of the vehicle is not involved. The vehicle motion control system includes a curve shape acquisition sectionfor acquiring a curve shape ahead of an own vehicle, an own vehicle position acquisition sectionfor acquiring a position of the own vehicle, and a vehicle motion control calculation sectionfor calculating a command value of a longitudinal acceleration generated for the vehicle based on the curve shape and the position of the own vehicle. The vehicle motion control calculation sectioncalculates a plurality of negative longitudinal acceleration command values during travel of the own vehicle from before a curve to a point where a curve curvature becomes constant or maximum after the vehicle enters into the curve. The longitudinal acceleration command values are changed based on at least one of: an estimate of the maximum lateral acceleration which is presumably generated during traveling a curve ahead of the own vehicle; a grade of the road ahead of the own vehicle, pedal operation by the driver, and a turning direction.

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Yokohama, Japan

Toshiya Oosawa