Toyota Jidosha Kabushiki Kaisha

Nippondenso Co., Ltd.

Toyota Jidosha Kogyo Kabushiki Kaisha

Aisin Seiki Kabushiki Kaisha

Olympus Optical Company, Ltd.

Aisin-warner Kabushiki Kaisha

Toyota Jidosha K.k.

Ken Asami

Kazunori Sakai

Shuuichi Buma

Kaoru Ohashi

Toshio Onuma

Noriyuki Nakashima

Kimio Tamura

Teruyoshi Wakao

Syouichi Masaki

Yutaka Okuda

Shouichi Masaki

Hiromi Maehata

Seitoku Kubo

Kazutaka Kuwana

Satoshi Hirano

Shinya Nakamura

Yukio Terakura

Toshio Yasui

Motoharu Naito

Shinichi Yamada

Masao Watanabe

Hiroyuki Ichikawa

Nobuyasu Nakanishi

Keiichi Ito

Tsuyoshi Yoshida

Tatsuo Sugitani

Kazuhiko Hayashi

Shinsuke Sakane

Kazuo Sato

Takeshi Ochiai

Shinichi Hori

Masashi Kishimoto

Shoichi Masaki

Shigeru Saito

Hideki Kabune

Kouji Hirao

Kohji Kamiya

Kiyoshi Miyake

Nobuyuki Yamaguchi

An apparatus for calculating vehicle-wheel revolution estimated values detects parameters such as the number of vehicle-wheel revolutions and vehicle-wheel revolution speeds, detects differences between the previous estimated values and the detected parameters or other parameters such as vehicle-wheel revolution speeds and accelerations calculated from the detected parameters, stores the differences at a predetermined rate, determines variations, and updates the estimated values based on the determined variations. Since the variations are determined so that the increase rate of the variations decreases as the accumulated values of the differences increase, lag time is minimized and at the same time noise is eliminated, thus precisely estimating the revolution values of the vehicle wheels. Antiskid control, traction control, and other controls can be effectively executed by using the estimated values even when the vehicle wheels move vertically on rough road surfaces or even when the vehicle wheels are eccentric. Consequently, the braking distance can be reduced, and the braking effects and the durability of control units are enhanced.

Apparatus for calculating vehicle-wheel revolution values

In an apparatus for detecting the abnormality of a rotational speed sensor adapted for, for example, an anti-skid control system, a time period within which a subsequent pulse will be generated by the rotational speed sensor in response to the rotation of a body of revolution such as wheel is estimated on the basis of the latest pulse interval of the pulses previously generated therefrom and a value corresponding to the force of inertia of the wheel developed on the braking operation thereof. The determination of abnormality of the rotational speed sensor is made when the subsequent pulse is not produced within the estimated time period. This is arranged based on the fact that the pulse interval depends upon the inertial force of the wheel. With the above arrangement, the abnormality detection of the speed sensor can be quickly made, so that a fail-safe control in a braking system can be speedily performed in response to the occurrence of abnormality of the speed sensor.

Detection of abnormality for rotational speed sensor

An antiskid control system is disclosed in which a single solenoid-operated switching valve connects a single wheel brake selectively to a high pressure or low pressure from a source of brake pressure. After the decompression of a wheel brake pressure, a repetitive intensifying operation is executed with a period of 40 msec in which an intensifying and a decompressing operation take place alternately. During the repetitive intensifying operation, the duty cycle for the intensifying operation is increased at a given rate. A flash intensification is executed immediately before the repetitive intensification. An initial value of the duty cycle for the repetitive intensification which occurs after the decompression of a second and a subsequent pass is chosen in proportion to the time duration of the previous repetitive intensifying operation and in inverse proportion to the immediately preceding decompressing interval.

Antiskid control system

In an all-phase de-energized state of the stepping motor, all motor windings having different phases are energized. After the all-phase de-energized state is detected, the motor windings are sequentially energized in accordance with predetermined phase energization patterns. Each of the energizations of the motor windings lasts for a given interval chosen to allow the stepping motor to generate a starting torque greater than a maximal load torque. After energizations of the motor windings corresponding to one cycle of the phase energization patterns are completed, durations of the energizations of the motor windings are gradually shortened to increase a rotational speed of the stepping motor.

Stepping motor control apparatus

A failure diagnosis system for a vehicle includes a failure detection means for detecting failures of devices or apparatuses installed in a vehicle, a storage means for storing failure information detected by the failure detection means, a failure display means for displaying failure information stored in the storage means, a time information means for adding failure information detected by the failure detection means and stored in the storage means to time information showing the time when the failure information is detected, a retrieval time input means for inputting a retrieval time and a selective display means for displaying selectively failure information which has time information being within the retrieval time.

Failure diagnosis system for vehicle

A wheel slipping control apparatus for controlling a braking hydraulic pressure to be applied to a wheel so as to perform an effective braking operation. The wheel slipping control apparatus comprises a control unit for generating a control signal in accordance with the wheel slipping state so as to perform a braking pressure control cycle so that the braking hydraulic pressure is set to a pressure decreasing mode and then to a pressure increasing mode. In the control unit, one of the braking pressure control cycles to be performed is determined as a learning control cycle to obtain a learning pressure-decreased value decremented in the learning control cycle and to obtain a learning pressure-increased value incremented in the learning control cycle. A present pressure-decreased value decremented in a control cycle after the learning control cycle is obtained to calculate a target pressure-increased value on the basis of the obtained learning pressure-decreased value and learning pressure-increased value whereby the braking hydraulic pressure is first increased to the vicinity of a wheel locking limit pressure after decreased in the pressure-decreasing mode.

Apparatus for controlling hydraulic pressure to be applied to effect

In an anti-skid control system for a motor vehicle there is provided a fail-safe control system for providing a compensation for a proper vehicle braking operation against the occurrence of failure of a hydraulic pressure control valve. The fail-safe control system includes a device for monitoring a control signal for controlling the operation of the control valve so that the hydraulic pressure applied to a wheel braking cylinder is regulated for preventing a wheel of the vehicle from skidding. The monitoring device detects the occurrence of failure of the control valve when the control signal indicative of one of the operation modes of the control valve is continuously generated more than a predetermined time period. In response to the detection, the fail-safe control system switches a directional control valve to the passage-opening condition so that the hydraulic pressure from a master cylinder can directly be applied to the wheel braking cylinder, thereby enabling the braking operation to be controlled by a vehicle driver.

Anti-skid control with fail-safe function

Disclosed is an antiskid control system for a vehicle wherein the rotational acceleration of a wheel of the vehicle is detected and the rate of variation of the detected acceleration is detected upon the onset of speed reduction of the wheel. A pressure modulator, which is located in a hydraulic line between a master cylinder and a wheel cylinder, is responsive to the detected rate of variation of acceleration to provide a pressure relief action on the fluid pressurized by the master cylinder and supplies the modulated fluid to the wheel brake cylinder.

Antiskid control system responsive to road surface reaction

A near rear suspension controller for a vehicle having a suspension between a vehicle body and a rear wheel includes: a front height detection section for measuring a distance between the vehicle body and a front wheel for generating a front height signal; a judgement section for generating a judgment result signal when the front height signal exceeds a predetermined range; and a rear height control section for increasing the rear vehicle height when it receives the judgment result signal.

Rear suspension controller

When a sporadic shock due to a protrusion or sinking of a road surface is detected at front wheels of a vehicle during its cruising on the road surface, the characteristic of the rear wheel suspension of the vehicle is immediately altered to improve the controllability and the stability of the vehicle or the feel of the ride thereof. For that purpose, a height sensor for detecting the distance between the body of the vehicle and each of the right and left front wheels thereof, a judgement section by which a front wheel vehicle height signal generated by the height sensor is compared with a predetermined reference range signal, and a controller for altering the characteristic of the rear wheel suspension of the vehicle depending on the result of the comparison are provided. In addition, a returning control of the characteristic of the suspension to the original state immediately after the rear wheels of the vehicle have passed over the protrusion or sinking which causes a sporadic shock may be performed. More effective control can be performed if these section are provided for the right and left wheels of the front and rear of the vehicle, respectively.

Rear wheel suspension controller

A rear suspension controller for controlling the suspension characteristic of a vehicle having a suspension which supports a vehicle body on plural wheels, wherein the acceleration of the vertical movement of at least one of the front wheels is measured and a corresponding signal is produced for detecting sporadic irregularities on a road surface. This acceleration signal is compared against preset reference signals and the characteristic of the rear suspension is altered, e.g., the suspension is made harder or softer, in dependence on the comparison in order to keep the controllability and stability or to maintain a good ride comfort according to demand. Additionally, the preset reference signals themselves are changed depending upon the vehicle speed because the influence of the shock caused by the irregularities changes according to the vehicle speed.

When a single shock due to a bump or dip in a road surface is detected at the front wheel of a vehicle running on the road, the characteristic of the air suspensions is immediately altered to improve comfort of ride thereof. For that purpose, a distance between the body of the vehicle and the front wheel is detected and when the distance exceeds a predetermined value, the suspension characteristic is altered to a softer state by communicating the air chambers of the front and the rear air suspensions. Further, the pressures of the air chambers are detected and, in case the pressure difference is greater than predetermined value, the communicating operation is prohibited in order to prevent an abrupt change of the vehicle posture.

Suspension controller

According to the present invention, as soon as the sporadic protrusion or sinking of a road surface is detected at the front wheel of the vehicle during its running on the road surface, the air chambers of the air suspensions for the right and the left rear wheels of the vehicle are connected to each other to alter the spring constant of the rear suspensions to `soft` when the rear wheel passes over the sporadic protrusion or sinking of the road surface, so that the feel of ride of the vehicle and the controllability and stability thereof are kept good. After the rear wheel moves over the sporadic protrusion or sinking, the characteristic of the rear suspensions is returned to the original state appropriate to the normal running state of the vehicle. Detectors for the sporadic protrusion or sinking of the road surface may be provided for the right and the left front wheels of the vehicle, respectively. The rear suspensions of the vehicle can be more appropriately controlled by that.

A rod actuator which includes a d.c. motor, a reduction gearing, a solenoid assembly which is used to define an intermediate stop position, and rotation stops. The angular extent through which an output shaft of the reduction gearing is rotatable is limited by a pair of limit stops. The solenoid assembly includes a plunger which is located intermediate the limit stops. A rotational stop is rotatably mounted on the output shaft and has a projection which is adapted to abut against the plunger to cease the motion of the rotational stop. The rotational stop is mounted on the output shaft so as to be rotatable relative thereto through a small angle by a lost motion, but is driven for integral rotation with the output shaft when such angle is exceeded. A lost motion connector is used so the angles of rotation where the rotation of the output shaft is stopped by the plunger during its clockwise and counter-clockwise rotations will be substantially equal. The actuator may be used in a shock absorber mounted on a vehicle to establish three levels, 'high', 'medium' and 'low', of attenuation exhibited by the shock absorber.

Apparatus for driving rod for rotation

A new rear suspension controller is invented for improving a ride comfort or for improving controllability and stability when a vehicle passes a sporadic bump or dip of otherwise smooth road surface. It includes: a front vehicle height detector which measures a distance between the vehicle body and a front wheel; a first judgment means which detects a sporadic bump or dip by comparing the signal from the front vehicle height detector with a preset standard value; a rear vehicle height detector which measures a distance between the vehicle body and a rear wheel; a second judgment means which detects the bump or dip that the front wheel has passed; and a rear suspension characteristic alteration means which alters, for example, a spring constant of air suspensions, a dumping force of shock absorbers, stabilizer compliance, etc. when the first judgment means detected the bump or dip and returns the characteristic after the second judgment means judges that the rear wheel has passed it.

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Nagoya, Japan

Ken Asami