Aisin Seiki Kabushiki Kaisha

Advics Co., Ltd.

Tetsuya Kuno

Tadashi Terazawa

Shingo Urababa

Harumi Ohori

Akihito Kusano

Kenji Asano

Satoshi Ishida

Masanobu Fukami

Akitaka Nishio

Toshiaki Hamada

Shiro Monzaki

Masahiro Inden

Tetsuaki Tsuzuki

Yoshinori Suzuki

A control device for an electric vehicle stopping at a slope road which reduces a power consumption of the electric motor when the vehicle is stopping at the slope road with the generation of a drive torque. The device judges the stopping state of the vehicle at the slope road when a condition that a throttle opening degree is not zero, that the drive torque is not zero, and that a vehicle speed is zero continues for a predetermined time, applies a hydraulic pressure P relative to wheel cylinder, and decreases the drive torque outputting to the motor to be zero. The device judges a release of the stopping state at the slope road when a condition that a throttle opening degree becomes greater than a throttle opening degree under the vehicle stopping state at the slope road, recovers the drive torque, and gradually releases an application of the hydraulic pressure to the wheel cylinder.

Control device for electric vehicle stopping at slope road

A hydraulic brake device for applying a braking force to a wheel of a vehicle which can detect an air-containing in a hydraulic circuit. The hydraulic brake device includes a hydraulic pressure generating device for generating and outputting a hydraulic pressure in accordance with a brake operational amount, a wheel cylinder operated by the hydraulic pressure directly or indirectly supplied from the hydraulic pressure generating device for applying a braking force to a vehicle wheel, a brake operational amount detection device for detecting the brake operational amount, a pressure sensor for detecting an output hydraulic pressure outputted from the hydraulic pressure generating device, and a controller for detecting an air-containing in a hydraulic circuit by a response time relating to a rise of the output hydraulic pressure detected by the pressure sensor relative to a start of a rise of the brake operation amount detected by the brake operational amount detection device.

Hydraulic brake device for vehicle

In a vehicle hydraulic brake system of a type adapted to release brake fluid discharged from the wheel cylinders into a reservoir for a master cylinder during pressure reduction phase of antilock brake control or vehicle stability control, the volume of the pressure chamber of the master cylinder can decrease until it becomes impossible to further increase pressure as a result of repeated pressure increase and reduction. An inexpensive solution to this problem is provided. The solution includes means for estimating the amount of pressure increase and/or pressure reduction of the wheel cylinders, and solenoid valves provided in a line connecting a pressure source with the master cylinder pressure chamber and adapted to be opened for a calculated time period.

Hydraulic brake system for vehicles

A vehicle motion control device reduces noise resulting from operation of a vacuum booster when an automatic pressure control is performed by properly controlling the energization of a linear solenoid of a booster actuator. An automatic hydraulic pressure generator is controlled in accordance with the vehicle motion condition and a hydraulic pressure control valve device is controlled to perform the automatic pressure control. A target electric current of the linear solenoid for actuating the vacuum booster is instantaneously increased to a starting target value which corresponds to an electric current value immediately before starting the operation of the vacuum booster and which is less than a maximum value of the target electric current, and then is gradually increased approximately to the maximum value of the target electric current.

Vehicle motion control device

The present invention is directed to a brake control system for an electrically operated vehicle, which is adapted to reduce a regenerative braking torque and add a hydraulic braking force. A motor control unit is provided for controlling an electric motor to apply a rotating force to a wheel and apply the regenerative braking torque to the wheel. A pressure control device is provided for controlling a hydraulic braking pressure generated by a pressure generator in response to operation of a manually operated braking member, and supplied to a wheel brake cylinder, which is operatively mounted on the wheel for applying a hydraulic braking force to the wheel. The regenerative braking torque is reduced in response to a braking condition monitored by a monitor. A pressure difference is detected between the hydraulic braking pressure of the brake fluid discharged from the pressure generator and the hydraulic braking pressure in the wheel brake cylinder. And, a characteristic of the regenerative braking torque to be reduced is modified in response to the pressure difference, to compensate for lack of regenerative braking torque by the hydraulic braking force, smoothly.

Brake control system for an electrically operated vehicle

The present invention is directed to a brake control system for an electrically operated vehicle which is adapted to reduce a regenerative braking torque and add a hydraulic braking force to compensate for lack of the regenerative braking torque, when voltage of a battery exceeds an upper limit. A motor control unit is provided for controlling an electric motor to apply a rotating force to a wheel and apply the regenerative braking torque to the wheel. A pressure control device is provided for supplying pressurized brake fluid to a wheel brake cylinder in response to operation of a manually operated braking member to apply the hydraulic braking force to the wheel. A reducing device is provided for reducing the regenerative braking torque when the voltage of the battery exceeds a predetermined upper limit. And, a compensation device is provided for actuating the pressure control device to supply the pressurized brake fluid to the wheel brake cylinder when the regenerative braking torque reduced by the reducing device exceeds a predetermined level, e.g., when a rate for reducing the regenerative braking torque exceeds a predetermined rate, or when a reduced amount of the regenerative braking torque exceeds a predetermined amount.

In an electrically operated vehicle in which a regenerative braking operation is performed to apply a regenerative braking torque to a wheel, if the regenerative braking torque reaches its maximum value and is insufficient to brake the wheel, a static hydraulic pressure outputted from a master cylinder is supplied to the wheel brake cylinder mounted on the wheel until the brake pedal reaches a retained position. Thereafter, a dynamic hydraulic pressure is supplied to the wheel brake cylinder. While the brake pedal is in movement from the rest position to the retained position, the wheel brake cylinder is supplied with only the static hydraulic pressure and while the brake pedal is being retained at the retained position the wheel brake cylinder is supplied with the static hydraulic pressure and the dynamic hydraulic pressure.

The present invention is directed to an anti-skid control system for controlling a braking force applied to road wheels including driven wheels of an electrically operated vehicle which has an electrical motor for driving the driven wheels. A hydraulic braking pressure is supplied to each wheel brake cylinder through an actuator. The actuator is controlled by a braking force controller into which output signals of wheel speed sensors are fed. A band-pass filter is provided for passing the wheel speeds of the driven wheels having an oscillation property within a predetermined band of frequencies, out of the wheel speeds detected by the wheel speed sensors. And, a coefficient of friction of a road is estimated to be relatively low when the output of the band-pass filter is in a predetermined range of frequencies. The hydraulic braking pressure in each wheel brake cylinder is controlled by the braking force controller in accordance with the estimated coefficient of friction and in response to the wheel speeds detected by the wheel speed sensors, thereby to control the braking force applied to each road wheel.

Growing community of inventors

Toyota, Japan

Tetsuya Kuno