Toyota Jidosha Kabushiki Kaisha

Nippondenso Co., Ltd.

Aisin Seiki Kabushiki Kaisha

Aisin Seiki K.k.

Toyota Jidosha K.k.

Kazunori Sakai

Ken Asami

Tatsuo Sugitani

Noriyuki Nakashima

Kimio Tamura

Hiroyuki Ichikawa

Nobuyasu Nakanishi

Kazutaka Kuwana

Tsuyoshi Yoshida

Masaru Kamikado

Kuniaki Okamoto

Teruyoshi Wakao

Syouichi Masaki

Hiromi Maehata

Yutaka Okuda

Shouichi Masaki

Satoshi Hirano

Masao Watanabe

Takashi Watanabe

Kiyoyuki Uchida

Akira Fukushima

Nobuhiko Makino

Hideo Inoue

Takeshi Ochiai

Shinichi Hori

Masashi Kishimoto

Shoichi Masaki

Takaaki Kato

Shusaku Fujimoto

Yoshio Hirano

Shinji Wakabayashi

Seizi Ishikawa

The traveling route guidance device includes a route acquisition unit that acquires a plurality of traveling routes from a current position of the vehicle to a destination, a gradient distribution acquisition unit that acquires a distribution of a gradient of each road surface of the plurality of traveling routes, a vehicle speed acquisition unit that acquires a vehicle speed of another vehicle traveling on each of the plurality of traveling routes, a load estimation unit that estimates a load of the vehicle when traveling on the traveling route based on the distribution of the gradient for each traveling route and the vehicle speed, and a notification unit that notifies the plurality of traveling routes and the load to an occupant of the vehicle.

Travel route guidance device and travel route guidance method

The anti-skid control system is capable of performing highly reliable anti-skid control through its accurate estimation of the vehicle speed and proper compensatory control even when sharp braking occurs or in the brake fluid pressure control on road surfaces with a low coefficient of friction likely to cause considerable fluctuations in wheel acceleration. The anti-skid control system is provided with a fluid pressure generating device, a fluid pressure controlling device, a wheel velocity detecting device, a standard speed setting device, a fluid pressure controlling mode setting device which sets either the pressure decrease mode or the pressure hold mode when the wheel velocity declines to a level lower than the standard speed and sets the pressure increase mode when the wheel velocity is equal to or higher than the standard speed. A maximum inflection point detecting device detects the maximum inflection point indicating the maximum value for the shift of the wheel velocity mentioned above from an increase to a decrease when the wheel velocity is not any lower than the standard speed. A fluid pressure controlling mode correcting device switches from the pressure increase mode mentioned above to either the pressure hold mode or the pressure decrease mode when the wheel velocity becomes equal to or higher than the standard speed and also becomes equal to or higher than the wheel velocity at the maximum inflection point.

Anti-skid control system

The anti-skid control system is constructed with a brake fluid pressure source for generating brake fluid pressure at high and low levers, a switching valve feeding either high pressure or low pressure to the wheel cylinders, a wheel velocity detecting device sensing the driving wheel rotating speed, an acceleration detecting device detecting the vehicle acceleration and a first arithmetic operation device for finding the estimated vehicle speed and the wheel rotating acceleration based on the wheel velocity detected by the wheel velocity detecting device and the vehicle body acceleration detected by the acceleration detecting device. A brake fluid pressure controlling device is provided for increasing, decreasing or maintaining the brake fluid pressure in the wheel cylinders, controlling the switching valve on the basis of wheel velocity, estimated vehicle speed, and wheel rotating acceleration. A second arithmetic operation device marks the minimum and maximum values in the wheel velocity after a brake fluid pressure reduction based on the wheel velocity detected by the wheel velocity detecting device calculates the recovery acceleration in the wheel velocity in the shift from the minimum value to the maximum value and compares the recovery acceleration with the set value. A vehicle acceleration correcting device corrects the vehicle body acceleration detected by the acceleration detecting device so as to set the vehicle body acceleration at a smaller value in case the recovery acceleration is less than the set value.

Anti-skid brake control system based on acceleration detection

An anti-skid control system for an automotive vehicle is provided with an actuator which is disposed in a hydraulic circuit between a pressure generator and a wheel brake cylinder. The actuator is arranged to control the hydraulic braking pressure applied to the wheel brake cylinder. In response to a wheel speed detected by a wheel speed detector, it is determined in an electronic control unit whether a condition for decreasing the braking pressure is effected. When this condition is effected, the decrease mode is provided in the control unit. When a predetermined period of time lapses after the decrease mode is initiated, the decrease mode is turned to a pressure control mode for applying the braking pressure to prevent the road wheel from being locked. When the condition is not effected during the predetermined period of time after the decrease mode is initiated, the decrease mode is turned to a direct supply mode for directly communicating the pressure generator with the wheel brake cylinder. Consequently, the lack of braking force caused by the delay of timing for decreasing the hydraulic braking pressure due to an erroneous detection of a locking condition of the road wheel on a rough road is effectively prevented.

Anti-skid control system for an automotive vehicle

The anti-skid control system is provided with wheel velocity sensors only for the driving wheels and yet is capable of performing the anti-skid control through its accurate estimation of the vehicle speed and proper compensatory control even when sharp braking occurs immediately upon the release of the accelerator after the occurrence of acceleration slip. The anti-skid control system is capable of starting the anti-skid control with certainty even when the braking operation is not detected because of a failure in the operation of the brake switch. The system is provided with a fluid pressure generating device, a fluid pressure controlling device, a brake operation detecting device, an acceleration detecting device, a wheel velocity detecting device, a braking force controlling device, a brake force correcting device and an acceleration slip detecting device.

A vehicle anti-lock brake control apparatus including a two-position direction control valve disposed between a wheel brake cylinder and a hydraulic pressure source, for increasing and decreasing the brake cylinder pressure, a slip detector for detecting a slip condition of the wheel, a controller for controlling the valve so as to prevent excessive slipping of the wheel, an averaging device for obtaining an average value of the wheel acceleration during a period until the detected slip condition deteriorates to a predetermined reference condition, and a device for determining a pressure decrease time substantially in reverse proportion to the average value of the wheel acceleration obtained when the slip condition has deteriorated to the reference condition, and supplying the controller with the determined pressure decrease time.

Anti-lock brake control apparatus including means for detecting average

An anti-skid control system for use in a motor vehicle having wheels whose rotational speeds are sensed by wheel sensors. The anti-skid control system decides the condition of the road-surface, on which the motor vehicle is running, on the basis of signals from wheel sensors. A reference speed is further calculated on the basis of the sensed speeds of the wheels symmetrically provided at the rear-right and rear-left sides with respect to the advancing direction of the motor vehicle. That is a selected one of an average value of the speeds of the rear-right and rear-left wheels sensed by the wheel sensors and the maximum one of the sensed rear-right and rear-left wheel speeds is selected in accordance with the decided road-surface condition. The reference speed is calculated on the basis of the selected one. A control unit of the anti-skid control system performs slip control of the wheels in accordance with the calculated reference speed. With this arrangement, the anti-skid control system can improve the braking efficiency and controllability irrespective of turning of the motor vehicle.

Anti-skid control system for use in motor vehicle

The invention is directed to an arrangement for monitoring a road condition which determines the coefficient of friction of the road surface on the basis of a signal corresponding to an acceleration of a vehicle detected by an acceleration sensor. The signal is converted into one of at least two predetermined values by conversion means in response to a magnitude of the acceleration every cycle of a predetermined time period. The converted value is summed up by summing means by a predetermined number of consecutive cycles to provide a total value in the last cycle thereof which is stored in memory means. Then, in determination means, one of at least two standard values is selected in response to the condition of increase or decrease of the total value in the present cycle provided by the summing means as compared with the total value in the previous cycle stored in the memory means. And, the total value in the present cycle is compared with the above one of at least two standard values to produce a road condition signal corresponding to a result of comparison which represents the coefficient of friction of the road surface. The present system is applicable to an anti-skid control system for an automotive vehicle.

Road condition monitoring system

The anti-skid control system is provided with wheel velocity sensors only for the driving wheels and is capable of performing the anti-skid control through its accurate estimation of the vehicle speed and proper compensatory control even when sharp braking occurs immediately upon the release of the accelerator after the occurrence of acceleration slip. The anti-skid control system is capable of starting the anti-skid control with certainty even when the braking operation is not detected because of a failure in the operation of the brake switch. The system is provided with a fluid pressure generating device, a fluid pressure controlling device, a brake operation detecting device, an acceleration detecting device, a wheel velocity detecting device, a braking force controlling device, a first estimated vehicle speed setting device and a second estimated vehicle speed setting device.

Sensors detect rotational speeds of respective vehicle wheels. A slip detection reference value is calculated from the detected rotational speeds of the vehicle wheels. Acceptable slip ranges for the respective vehicle wheels are determined in accordance with the calculated slip detection reference value. The rotational speeds of the vehicle wheels are compared with the corresponding acceptable slip ranges respectively. Slip controls of the respective vehicle wheels are performed when the rotational speeds of the vehicle wheels reside outside the corresponding acceptable slip ranges respectively. The highest of at least two of the rotational speeds of the vehicle wheels is selected. Differences between the respective rotational speeds of the vehicle wheels and the selected highest vehicle wheel rotational speed are calculated. The slip detection reference value is corrected in accordance with the respective calculated differences.

Vehicle wheel slip control system

An apparatus for controlling running of a motor vehicle by measuring respective values of acceleration of the vehicle wheels, includes a digital low-pass filter for obtaining acceleration values by excluding high-frequency noise components of successive values of instantaneous acceleration which are obtained for each wheel at successive sampling intervals. Filter parameters such as the cut-off frequency can be controlled in accordance with the current operating conditions of the respective wheels, such as wheel velocity, to thereby provide optimum filter operation and hence substantially improved accuracy for the derived values of acceleration.

Motor vehicle running control apparatus

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

A cycle time of pulses converted from an electrical signal generated at a rotational sensor is counted. In determining a cycle of the pulses, either a rising edge or a falling edge of the pulse is selected. As the selection of the either edge affects accuracy of the rotational speed measurement, two modes are proposed. One is suitable for a lower speed range in which either of the rising and falling edges is selected for every pulse monitoring period considering the relative phase position of the pulse and the pulse monitoring period. The other is suitable for a higher speed range in which one fixed edge is utilized. Here the edge is selected depending on the winding direction of the electric wire of the pick-up coil of the rotational sensor and independent of the pulse monitoring period.

Rotational speed sensor with unfixed and/or fixed edge speed calculation

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.

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Aichi, Japan

Kazunori Sakai