Mazda Motor Corporation

Toshiaki Tsuyama

Kazutoshi Nobumoto

Makoto Kawamura

Toru Onaka

Fumio Kageyama

Haruki Okazaki

Akira Sone

Kaoru Sotoyama

Toshihiro Matsuoka

Tomoji Izumi

Eiji Nishimura

Tetsuya Tachihata

Eizi Nishimura

Yutaka Tsukahara

Masao Hideshima

Yoshihisa Nakamoto

Yoji Kurihara

Yoshinori Fukumoto

Tomoyuki Hirao

Makoto Teshima

Kensuke Hayafuchi

Sotetsu Yoshida

An automotive vehicle stability control system determined which is a main cause of a change in a change rate of a yaw rate difference of an actual yaw rate from a target yaw rate between a change in the actual yaw rate and a change in the target yaw rate when the change rate of the yaw rate difference exceeds a specified change rate, increase threshold slip angle for starting braking control based on slip angle following the driver's intention when the main cause is the change in the actual yaw rate and increases an upper limit of target slip angle so as to allow the target slip angle to be increased according to a driver's steering operation when the slip angle preferential braking control takes place.

Stability control system for automotive vehicle

A system of driving stability control, which is adapted to control valves for opening and closing hydraulic pressure passages between a master cylinder and brake units of wheels and simultaneously controls pressurizing valves and a pressure relief valves so as to supply braking force selectively and independently to the brake units when a specified driving condition is detected, performs the coordinated braking control that, when a specified step-on pressure is detected during execution of the driving stability control, delivers the braking pressure to the brake units according to brake pedal travels as the driving intends simultaneously with reducing the participative degree of the driving stability control so as to ensure gripping force of wheels that brake the vehicle and reduces reduce the participative degree of the driving stability control with an intention of regarding driving stability of the vehicle as important when the vehicle is going to cause a spin.

Stability control system for vehicle

An engine control system for an automotive vehicle for controlling slippage through fuel-cut and ignition retardation makes a correction in which an engine output control parameter is changed smaller every time a low slippage continuing time reaches each of predetermined threshold times so as to increase engine output, thereby improving acceleration of the vehicle.

Traction control system for vehicles

A traction control system for a motor vehicle has a four wheel steering device for controlling a steering characteristic of the vehicle based on a yaw rate difference between an actual yaw rate and a target yaw rate of the vehicle. The traction control system further has a device for controlling driven torque applied to a driven wheel while a slip is generated in the driven wheel. A correction device is used for correcting the driven torque to be small as a wheel steering angle becomes large while the four wheel steering device is operated.

Traction control system for motor vehicle

A slip control system for a motor vehicle controls slippage of driving wheels and includes a sensor for detecting a slip ratio of each driving wheel, a device for decreasing slip of each driving wheel by controlling a driving force transmitted to the driving wheel so that the slip ratio of the driving wheel is at least equal to a predetermined desired slip ratio when the slip ratio of the driving wheel is equal to the desired slip ratio, a sensor for detecting a yawing rate of the vehicle, and a sensor for detecting a steering amount of the vehicle. The slip decreasing device includes a correcting device for decreasing the desired slip ratio when a steering condition is detected based on amounts detected by both the yawing rate detecting sensor and the steering amount detecting sensor.

Slip control system for motor vehicle

A traction control device operates to determine the speed of each of the left and right drive wheels of a vehicle, determine the speed of each of the left and right passive wheels of the vehicle, calculate the actual slip rate of the drive wheels of the vehicle directly based on the measurements of the speeds for the drive and passive wheels, establish a target slip rate and control the driving condition of the vehicle by making the actual slip rate equal the target slip rate. The actual slip rate is matched to the target slip rate by controlling engine output and braking power. The step of controlling the driving condition of the vehicle by controlling the engine output and the braking power is carried out according to the time differential of the difference between the actual slip rate and the target slip rate at least until the actual slip rate matches the target slip rate for the first time. After the actual slip rate has matched the target slip rate at least once, the step of controlling is carried out according to the proportion of the difference between the actual and the target slip rates.

Traction control device for vehicles

When a wheel slip value of the driven wheel relative to a surface of road becomes excessive during acceleration, torque to be applied to the driven wheels is controlled by the traction control so as to make the actual wheel slip value of the driven wheel become a predetermined target value. There is counted the duration of time during which the actual wheel slip value of the driven wheel becomes smaller than a predetermined threshold value set as a value smaller than the target value, and a control value for the traction control is corrected in accordance with the duration of time counted. This correction is implemented so as to increase the torque to be applied to the driven wheels larger as the duration of time counted becomes longer. The control value to be corrected includes the target value itself or a road surface friction coefficient .mu. as a parameter for setting the target value.

Traction control system for an automotive vehicle utilizing a wheel slip

A traction control system for a motor vehicle having driving wheels and driven wheels includes a device for detecting the speed of each of the driving wheels of the vehicle, a device for detecting the speed of each of the driven wheels of the vehicle, a device for calculating a slip value of the driving wheels based on the detected speeds of the driving and driven wheels, a traction control device for controlling the driving wheel so that the slip value of each driving wheel is equal to a predetermined desired slip value when the slip value of each driving wheel is greater than the predetermined desired slip value, and a device for estimating a friction coefficient of a road surface which is employed when the predetermined desired slip value is determined. If slip of the driving wheel occurs when the vehicle is started, the estimating device calculates an acceleration of the driving wheel. The friction coefficient of the road surface is estimated based on an engine output when the acceleration of the driving wheel is greater than a predetermined value.

Traction control system using estimated road surface friction coefficient

A vehicle slippage control system has wheel drive torque controlled so as to prevent drive wheels from excessively slipping on a road and is regulated in accordance with road surface resistances. The system estimates lateral and rectilinear road surface resistances on the basis of lateral and rectilinear gravitational acceleration of the vehicle, respectively, and then selects one of the estimated lateral and rectilinear road surface resistances, on the basis of predetermined terms, as an effective road surface resistance in accordance with which wheel drive torque is changed.

Slippage control system using estimated road surface resistances

The braking force to the driven wheels is subjected to feedback control so as to allow the actual slip value of the driven wheels to agree with a predetermined target value for controlling the brake. The control amount for the feedback control is determined by differentiation control. The feedback control amount contains a first control amount corresponding to a predetermined basic travelling state and a second control amount corresponding to a particular travelling state. In ordinary travelling state, the braking force is controlled by the first control amount, and the braking force is controlled by the second control amount when the automotive vehicle is travelling in such a particular state. When the the vehicle is travelling on a bad road, the second control amount is set so as to loosen the braking force, as compared with the first control amount. Alternatively, when the vehicle is cornering, the second control amount is set as to tighten the braking force as compared with the first control amount.

Traction control system for automotive vehicle

A traction control system for a motor vehicle having driving wheels and driven wheels includes a device for detecting the speed of each of the driving wheels of the vehicle, a device for detecting the speed of each of the driven wheels of the vehicle, a device for calculating a slip value of the driving wheels based on the detected speeds of the driving and driven wheels, a traction control device for controlling the driving wheel so that the slip value of each driving wheel is equal to a predetermined desired slip value when the slip value of each driving wheel is greater than the predetermined desired slip value, and a device for estimating a friction coefficient of a road surface which is employed when the predetermined desired slip value is determined. The estimating device calculates, in a first predetermined time period immediately after the traction control is started, an acceleration of the driven wheel based on a speed difference of the driven wheel during a second predetermined time period and an acceleration of the driven wheel based on a speed difference of the driven wheel during a third predetermined time period after the first predetermined time period has passed. The estimating device then estimates the friction coefficient of the road surface by using the calculated acceleration of the driven wheel.

A traction control system for a motor vehicle having driving wheels and driven wheels includes a device for detecting the speed of each of the driving wheels of the vehicle, a device for detecting the speed of each of the driven wheels of the vehicle, a device for calculating a slip value of the driving wheels based on the detected speeds of the driving and driven wheels, a traction control device for controlling the driving wheel so that the slip value of each driving wheel is equal to a predetermined desired slip value when the slip value of each driving wheel is greater than the predetermined desired slip value, and a device for estimating a friction coefficient of a road surface which is employed when the predetermined desired slip value is determined. The estimating device updates the friction coefficient of the road surface previously estimated with the friction coefficient of the road surface newly estimated when the slip value of the driving wheel is located in a predetermined region.

A slip control device includes a slip detecting device for detecting a slip rate of a drive wheel, an engine control device for reducing an engine output when the slip rate exceeds a first threshold value, and a brake control device for applying a brake force on the drive wheel when the slip rate exceeds a second threshold value. A frictional coefficient detecting device detects a frictional coefficient of a road, on which the vehicle is running, and a threshold determining device provides the first and second threshold values in accordance with the frictional coefficient. The engine output control and brake force control can be effectively utilized for the slip control in the traction control.

Slip control device for vehicle wheel

A traction control system for a vehicle has a sub-throttle valve provided in an intake passage of the engine in series to a main throttle valve which is operatively connected to an accelerator pedal to open and close in response to operation of the accelerator pedal. An engine output controller controls opening of the sub-throttle valve to control the output of the engine so that the slip value of the driving wheels converges on a target slip value. The engine output controller once moves the sub-throttle valve to an initial opening when the slip value of the driving wheels exceeds the target slip value and then controls the opening of the sub-throttle valve to control the output of the engine so that the slip value of the driving wheels converges on a target slip value. The initial opening is set to be a fixed value when the opening of the main throttle valve is not larger than a predetermined opening and to be substantially equal to the opening of the main throttle valve when the opening of the main throttle valve is larger than the predetermined opening. The fixed value is not smaller than the predetermined opening of the main throttle valve.

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Hiroshima, Japan

Toshiaki Tsuyama