Traction control method for stabilizing motor vehicle motion in the event of increased driving wheel slip

• US 5,564,800 A
• Filed: 05/30/1995
• Issued: 10/15/1996
• Est. Priority Date: 05/28/1994
• Status: Expired due to Fees

• Current Assignee: DaimlerChrysler AG (Mercedes-Benz Group AG)
• Original Assignee: Mercedes-Benz AG (Mercedes-Benz Group AG)
• Inventors: Pfister, Carola, Baumann, Matthias, Fischle, Gerhard, Klingel, Ralph
• Primary Examiner(s): Oberleitner, Robert J.
• Assistant Examiner(s): Poon, Peter M.
• Application Number:
  US08/452,997
• Time in Patent Office: 504 Days
• Field of Search: 303/139, 303/140, 303/144, 303/150, 303/149, 364/426.01-426.03
• US Class Current: 303/140
• CPC Class Codes: B60T 2201/16 Curve braking control, e.g. turn control within ABS control algorithm
• CPC Class Codes: B60T 8/175 Brake regulation specially adapted to prevent excessive wheel spin during vehicle acceleration, e.g. for traction control safety devices for propulsion unit control responsive to, or preventing, skidding of wheels B60K28/16
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02

Abstract

A method controls the driving stability in the event of increased slip at the driving wheels of a motor vehicle having an electronic traction system with braking intervention at the driving wheels. With excessive high-adhesion wheel slip, synchronous braking intervention on both sides is undertaken at the driving wheels when the vehicle is travelling around a curve. A reduction takes place in the brake pressure at the low-adhesion wheel, as used for controlling drive slip or increasing traction, when the vehicle is travelling in a straight line, the high-adhesion wheel slip is used as the control parameter in either situation. This method permits braking interventions at the driving wheels for the purpose of controlling drive slip and/or for increasing traction while still maintaining a high level of driving stability.

Claims

1. A method of traction control for stabilizing driving of a motor vehicle, comprising the steps of

(a) using braking interventions at the driving wheels in the event of increased slip at driving wheels as a function of whether the motor vehicle is one of travelling around a curve and in a straight line, and further as a function of the vehicle speed,

(b) monitoring whether high-adhesion wheel slip is above a specified limit and whether vehicle speed is in a range between a specified lower limiting speed and a specified upper limiting speed and, if a response is positive, using the high-adhesion wheel slip as the control parameter;

(c) effecting brake pressure at the driving wheels on both sides of the motor vehicle with synchronous brake pressure control upon recognizing that the motor vehicle is travelling around a curve, and

(d) reducing brake pressure which increases traction at the low-adhesion wheel upon recognizing that the motor vehicle is travelling in a straight line.

2. The method according to claim 1, wherein braking action on both sides of the motor vehicle to stabilize the motor vehicle when travelling around a curve is terminated when the motor vehicle is no longer travelling around a curve, when the vehicle speed is no longer within the specified range, when the high-adhesion wheel slip drops below a specified limit or when a specified maximum braking intervention duration has been exceeded during travelling around a curve.

3. The method according to claim 1, wherein brake pressure present at the low-adhesion wheel to increase traction is retained when the vehicle speed is below the specified lower speed and the high-adhesion wheel slip is below a specified upper limit even with a system recognition that the vehicle is travelling in a straight line and the high-adhesion wheel slip is below a specified lower limit.

4. The method according to claim 3, wherein braking action on both sides of the motor vehicle to stabilize the motor vehicle when travelling around a curve is terminated when the motor vehicle is no longer travelling around a curve, when the vehicle speed is no longer within the specified range, when the high-adhesion wheel slip drops below a specified limit or when a specified maximum braking intervention duration has been exceeded during travelling around a curve.

5. The method according to claim 1, wherein, for at least one of undertaking braking action on both sides of the motor vehicle to stabilize the motor vehicle when travelling around a curve, and for reducing in the brake pressure at the low-adhesion wheel to increase traction, the lower limiting speed is 15 km/h and the upper limiting speed is 80 km/h.

6. The method according to claim 5, wherein braking action on both sides of the motor vehicle to stabilize the motor vehicle when travelling around a curve is terminated when the motor vehicle is no longer travelling around a curve, when the vehicle speed is no longer within the specified range, when the high-adhesion wheel slip drops below a specified limit or when a specified maximum braking intervention duration has been exceeded during travelling around a curve.

7. The method according to claim 6, wherein brake pressure present at the low-adhesion wheel to increase traction is retained when the vehicle speed is below the specified lower speed and the high-adhesion wheel slip is below a specified upper limit even with a system recognition that the vehicle is travelling in a straight line and the high-adhesion wheel slip is below a specified lower limit.