Nippondenso Co., Ltd.

Toyota Jidosha Kabushiki Kaisha

Sharp Corporation

Noriyuki Nakashima

Kimio Tamura

Ken Asami

Kazunori Sakai

Teruyoshi Wakao

Syouichi Masaki

Yoshinori Ishiguro

Nobuhiko Makino

Shouichi Masaki

Kohji Kamiya

Kazumasa Nakamura

Akira Fukushima

Hiroshi Miyata

Masami Itou

Shinichi Hori

Eiju Matsunaga

Yutaka Okuda

Hideki Kabune

Naoyasu Sugimoto

Kazuo Masaki

Kiyoshi Miyake

Motoji Suzuki

Shinya Takemoto

Kunimi Masuto

Hisashi Kinoshita

Mikio Tanabe

Toshiyuki Murai

A suspension control system capable of controlling a suspension of an automotive vehicle in such a manner as to improve the riding comfort and maneuverability of the vehicle without the need for many sensors is disclosed, in which a speed difference signal obtained by subtracting an estimated vehicle speed from a wheel speed is filtered with band-pass filters which pass sprung resonance frequency components and unsprung resonance frequency components, respectively. After amplification, the filtered speed difference are compared with a reference value so that a damping force of a shock absorber is set in accordance with a road surface condition. Since the damping force of the shock absorber is shifter by using only information based on the wheel speed detected by a wheel speed sensor, a total number of sensor to be mounted on the vehicle for controlling the suspension can be considerably reduced. The suspension control system is simple in construction and can be manufactured at a relatively low cost.

Suspension control system for controlling suspension of automotive

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

An apparatus for detecting a disconnection of a sensor by monitoring a signal in a signal-carrying line for receiving an output signal of the sensor through a connector. The apparatus includes a feeder circuit for causing a current to flow through the connector to the sensor for a predetermined time period in the absence of the output signal of the sensor. The current flow causes elimination of an oxide film produced in the connector with time, resulting in the prevention of attenuation of the output signal due to the oxide film and in ensuring accurate detection of the disconnection of the sensor irrespective of secular change.

Apparatus for detecting disconnection of a speed sensor and eliminating

A vehicle height sensor includes switching circuits which are turned on and off in accordance with height of a vehicle. The vehicle height sensor is driven when a drive signal is outputted to the sensor. A preset voltage is fed to terminals of the respective switching circuits via resistors. Voltages at the terminals are outputted as vehicle height data having bits corresponding to the respective switching circuits. When the output of the drive signal is suspended, the vehicle height data are read as vehicle height sensor malfunction detecting data. The malfunction detecting data are compared to preset reference data. The vehicle height sensor is judged to be wrong when the malfunction detecting data differ from the preset reference data.

Vehicle height detecting system

In an antiskid control system, the acceleration of a vehicle wheel is detected and compared with a predetermined value. A first count value is incremented in response to the detection of the wheel acceleration exceeding the predetermined value. When this first count value exceeds a reference count within a first preset period, the road is interpreted as having a rough surface and a second count value is similarly incremented in response to the detection of the wheel acceleration exceeding the predetermined count. If the second count value does not reach the reference count within a second preset period longer than the first preset period, the road is interpreted as having a smooth surface. The gradient of brake hydraulic pressure of the vehicle is controlled in response to the different interpretation of the road surface.

Antiskid control with surface roughness compensation

A pulse signal is generated by a wheel speed sensor with a frequency proportional to the speed of rotation of a vehicle wheel, the pulse signal comprising a plurality of frames each having a series of a predetermined number of pulses which are tended to be affected by noise and pulse mutilation. Pulses in each frame are counted and from the count is derived an instantaneous wheel speed value. The difference between the successively derived instantaneous speed values is taken and compared with a predetermined threshold. A first or a second indication is given in response to the difference being lower or higher than the threshold, respectively. If the first indication is given, output signals representing the average wheel speed and average wheel acceleration of the wheel are derived from the instantaneous speed values of successive frames. If the second indication is given, the instantaneous speed value of the previous frame is used instead of the instantaneous value of the subsequent frame which is disturbed by noise or pulse mutilation to derive the output signals.

Wheel speed and acceleration detection immune to disturbance

In an antiskid control system for the hydraulic braking system of a wheeled vehicle, the rotational speed of a vehicle wheel and the acceleration of the wheel are detected and levels of road surface friction are determined on the basis of the wheel speed and acceleration to give a first indication that the road has a high value of friction or a second indication that the road has a low value of friction. The wheel speed and acceleration are analyzed to detect a down-pressure mode to decrease the fluid pressure of the braking system and an up-pressure mode to increase the pressure. In response to the presence of the first indication, the down-pressure mode is effected at a lower rate and then at a higher rate. In response to the occurrence of the second indication, the down-pressure mode is effected at the higher rate.

Antiskid control with surface friction compensation

In an antiskid control system for a motor vehicle, the speed and acceleration of at least one vehicle wheel are detected, and from the detected wheel speed, the speed of the vehicle is estimated. First and second variable threshold values are derived from the vehicle speed. The wheel speed and acceleration are compared with the first and second thresholds, respectively, to estimate the level of road surface friction and to operate solenoid-operated hydraulic brake pressure decreasing means. The operating period of the pressure decreasing means is controlled in accordance with the estimated road surface friction to prevent excessive reduction of the brake pressure and premature locking of the wheels.

Antiskid control with surface friction compensation by prolonged

A shock absorber control system for controlling the damping force of a variable shock absorber comprises a speed sensor for generating a signal indicative of the wheel speed of at least one wheel of the vehicle and a control unit for controlling the damping force. The control unit derives the acceleration from the wheel speed signal and compares the derived acceleration with upper and lower references. The damping force control is effected when the acceleration varies successively so as to assume both values outside the range between the upper and lower references.

Vehicle shock absorber control system

In an antiskid control system the speed of a vehicle wheel is compared with a variable threshold which is a function of the speed of the vehicle and a first comparator output is generated when the speed is lower than the variable reference. The acceleration of the wheel is compared with a predetermined threshold for generating a second comparator output when the acceleration is lower than the threshold or a third comparator output when the acceleration is higher than the threshold. The fluid pressure of the braking system is lowered in response to there being a simultaneous presence of the first and second comparator outputs and raised in response to there being a simultaneous presence of the first and third comparator outputs.

Antiskid control with wheel-speed difference compensation

A road surface condition discriminating system is disclosed, in which a vehicle speed signal produced from a vehicle speed sensor mounted on a part of the wheel system of an automobile running on a road is analyzed to decide the road surface conditions on the basis of the variations in the wheel revolutions. The system computes the acceleration from the derivative of the measured speed and then various actuating devices of the vehicle, such as, height control, shock absorber control, power steering control and skid control are controlled from the decision on the road condition.

Road condition discriminating system

A shock absorber control system controls vehicle shock absorbers by bringing them selectively into a softer dampening mode or a harder dampening mode in response to operation of a steering wheel of a vehicle. The shock absorbers are changed from the softer to the harder dampening mode only when the vehicle speed is higher than a reference vehicle speed and the steering wheel is turned at an angular velocity greater than a predetermined reference angular velocity. The angular velocity of rotation of the steering wheel is used as a parameter to select one of the softer and harder dampening modes only when the vehicle wheel has been angularly moved beyond a certain reference angle dependent on the vehicle speed. Therefore, no unwanted switching between the softer and harder dampening modes takes place when the steering wheel is angularly moved back and forth through relatively small angles. The harder dampening mode continues for a preset interval of time.

Shock absorber control system

A rotary position control device is provided with a three-rotary position controlling mechanism. The control device includes a disk member having a toothed portion on its circumferential part, to which an output shaft is secured in order to drive a driven source coupled to the output shaft. The disk member further has a circumferentially spaced slot having a recessed portion provided halfway between the both ends, the both ends and the recessed portion functioning as first, second and third stopper portions which receive a rod member disposed in the slot. The disk member stops its rotation when the rod member engages the both ends of the slot of the disk and also when the rod member engages the recessed portion, this third stop position of the disk member being achieved only when the electromagnetic solenoid is energized, thus causing the required relative movement between the output shaft and the driven source coupled to the output shaft. A motor as a motive source is housed in the control device to rotate the disk, which is supplied a driving signal from the exterior of the rotary position control device.

Three-rotary position control device

In an antiskid control system, first and second wheel speed values are derived from pulse signals supplied from wheel speed sensors to indicate respectively the rotational speeds of first and second wheels of the vehicle. A trimming value is derived from the difference between the first and second wheel speed values and used as a multiplier by which the first wheel speed value is multiplied to compensate for the deviation of the speed of the first wheel with respect to the speed of the second wheel. The compensated first wheel speed value compared with a variable threshold that is a function of the speed of the vehicle to determine the down pressure timing.

A shock absorber control system for a motor vehicle having shock absorbers in which the system comprises a vehicle speed sensor and an operation control device for calculating acceleration and deceleration of the vehicle in accordance with the vehicle speed signal from the speed sensor and for producing control signals to the shock absorbers, thereby regulating the attenuation forces of the shock absorbers in accordance with road conditions.

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Nagoya, Japan

Noriyuki Nakashima