Mazda Motor Corporation

Makoto Kawamura

Kazutoshi Nobumoto

Toshiaki Tsuyama

Fumio Kageyama

Haruki Okazaki

Toru Onaka

Akira Sone

Kaoru Sotoyama

Masao Hideshima

Kensuke Hayafuchi

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 slip control system for a vehicle having rear right and left drive wheels includes a traction control for controlling a slip rate of a wheel by controlling a braking hydraulic pressure for the wheel under a non-braking condition. The slip rate of a wheel is controlled, by controlling the braking hydraulic pressure for the wheel under a braking condition, so as to provide an anti-skid control. A start of the control of the slip rate is restricted by the anti-skid control. The control of the slip rate by the anti-skid control is applied commonly to the right and left drive wheels, while the control of the slip rate by the traction control is applied independently to the right and left drive wheels. The anti-skid control can be always properly carried out without being affected by the traction control.

Vehicle slip control system

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.

Traction control system for motor 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 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.

Traction control system for vehicle

A slip control system for a motor vehicle controls respective braking forces in right and left driving wheels and controls an engine output by controlling a throttle opening of a throttle valve so that a slip value of the driven wheel becomes less than a target slip value. The system includes a device providing a basic control amount of the throttle opening based on the slip value of the driven wheel and the target slip value, a device for detecting respective brake fluid pressures in the right and left driven wheels, a device for converting the detected brake fluid pressure into an engine output, a device for providing a correction control amount of the throttle opening by subtracting an amount of the throttle opening corresponding to the converted engine output from the basic control amount of the throttle opening, and a device for driving the throttle valve by the basic control amount of the throttle opening when the brake fluid pressures in the right and left driven wheels are increased or increased rapidly, and driving the throttle valve by the correction control amount of the throttle opening when the brake fluid pressures in the right and left driven wheels are not increased or increased rapidly.

A traction control system for a motor vehicle having driving wheels and driven wheels. The traction control system comprises sensors for detecting a speed of each of the driving wheels of the vehicle; sensors for detecting a speed of each of the driven wheels of the vehicle; and a mechanism for calculating a slip value of the driving wheels based on the detected speeds of the driving and driven wheels. The traction control system also includes an engine output control mechanism for controlling each of the driving wheels so that the slip value of each of the driving wheels is controlled to become equal to a predetermined first desired slip value when the slip value of each driving wheel is greater than the predetermined first desired slip value; and a brake force control mechanism for controlling each of the driving wheels so that the slip value of each of the driving wheels is controlled to become equal to a predetermined second desired slip value when the slip value of each driving wheel is greater than the predetermined second desired slip value. The control system also includes an engine control restriction mechanism for restricting the engine output control mechanism while the braking control is carried out.

A slip control system for a vehicle having a differential which distributes engine output to left and right driving wheels suppresses the engine output when the slip of at least one of the driving wheels exceeds a first threshold value. Slips of the left and right driving wheels are periodically detected, and a spin pattern of the driving wheels is periodically determined on the basis of the slips of the left and right driving wheels. Whether the vehicle is running on a split surface road, where the parts of the road surface in contact with the left and right driving wheels have different friction coefficients, is determined on the basis of the present spin pattern and the preceding spin pattern according to a predetermined split surface determining rule. When it is determined that the vehicle is running on a split surface road, the first threshold value is increased.

A slip control system for a motor vehicle controls slips in driving wheels and includes a sensor for detecting a slip ratio of each driving wheel and a traction control system for decreasing a slip of each driving wheel by controlling a driving force transmitted to each driving wheel so that the slip ratio of each driving wheel is at least equal to a predetermined desired slip ratio when the slip ratio of the driving wheel becomes equal to the desired slip ratio. An automatic transmission control system controls an automatic transmission by using a first shift property for a normal operation, and a second shift property for a traction control operation which is adapted to determine a relative higher speed stage. A device is provided for switching the first shift property to the second shift property when the traction control operation is started by the traction control system.

A vehicle traction control device having a control device for controlling the torque of the drive wheels by controlling the throttle in order to match the slip rate of the drive wheels with a target slip rate in order to prevent excessive slip caused by excessive torque in the drive wheels. The traction control is provided with a device for determining whether or not the road being driven on is a rough road or not. When the above device sends a signal to the control that the road is rough, the engine gain in the throttle is made smaller when the throttle closed relative to the engine gain and throttle of a normal road. In another embodiment, when the road is rough, the engine gain is made larger when the throttle is opened relative to the engine gain and throttle of a normal road. Also disclosed is a control in which the engine gain in the throttle control is made larger when the throttle is opened and is made smaller when the throttle is closed relative to the engine gain and throttle of a normal road. A process for controlling traction is also disclosed.

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Hiroshima, Japan

Makoto Kawamura