System and method for reducing stopping distance and improving traction in motor vehicles

• US 6,663,113 B2
• Filed: 11/20/2001
• Issued: 12/16/2003
• Est. Priority Date: 10/09/1998
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schülke, Armin, Verhagen, Armin-Maria, Stoller, Roland
• Primary Examiner(s): Dickson, Paul N.
• Assistant Examiner(s): To, Toan C
• Application Number:
  US09/989,356
• Publication Number:
  US 20020109309A1
• Time in Patent Office: 756 Days
• Field of Search: 280/5.505, 303/113.2, 303/144, 303/146, 303/148, 303/149, 303/150
• US Class Current: 280/5.505
• CPC Class Codes: B60G 17/0165 to an external condition, e.g. rough road surface, side wind
• CPC Class Codes: B60G 21/0553 adjustable
• CPC Class Codes: B60G 2400/61 Load distribution
• CPC Class Codes: B60G 2400/822 Road friction coefficient determination affecting wheel traction
• CPC Class Codes: B60G 2800/012 Rolling condition
• CPC Class Codes: B60T 2260/024 Yawing moment compensation during mu-split braking
• CPC Class Codes: B60T 8/1764 Regulation during travel on surface with different coefficients of friction, e.g. between left and right sides, mu-split or between front and rear
• CPC Class Codes: B60W 2552/40 Coefficient of friction

Abstract

A method for improving the traction between a road surface and a motor vehicle having a pair of front wheels and a pair of rear wheels which engage the road, each front wheel mounted on a front axle, each rear wheel mounted on a rear axle, one of the axles being a driven axle, and a two-part undercarriage roll stabilizer system including a front and a rear undercarriage stabilizer, each the undercarriage stabilizer comprising an actuating drive operatively coupled to a the pair of wheels, and for reducing the stopping distance along the road in which the motor vehicle can be stopped. The method includes: determining a coefficient of friction between at least two wheels and the road surface; comparing the coefficients of friction; and tensioning the actuating drives diagonally, the wheel contact forces between diagonally opposite wheels and the road surface thereby being one of increased and decreased in response to the determined coefficient of friction between a wheel and the road surface. Also, a system for carrying out this method in a motor vehicle.

Claims

1. A method for improving the traction between a road surface and a motor vehicle having a pair of front wheels and a pair of rear wheels which engage the road surface, each front wheel mounted on a front axle, each rear wheel mounted on a rear axle, one of the axles being a driven axle, and a two-part undercarriage roll stabilizer system including a front and a rear undercarriage stabilizer, each the undercarriage stabilizer comprising an actuating drive operatively coupled to a the pair of wheels, and for reducing a stopping distance of the vehicle along the road a stopping distance of the vehicle, the method comprising:

determining a coefficient of friction between at least two wheels and the road surface;

comparing the coefficients of friction; and

tensioning the actuating drives diagonally, such that the wheel contact forces between diagonally opposite wheels and the road surface thereby being one of increased and decreased in response to the determined coefficient of friction between a wheel and the road surface.

2. The method according to claim 1, further comprising increasing a load on a front wheel with substantially the highest coefficient of friction and on a rear wheel with substantially the lowest coefficient of friction, and simultaneously reducing a load on a front wheel with substantially the lowest coefficient of friction and on a rear wheel with substantially the highest coefficient of friction, whereby the stopping distance is reduced.

3. The method according to claim 1, further comprising increasing a load on a wheel having substantially the lowest coefficient of friction and mounted to the driven axle, whereby traction between that wheel and the road surface is increased.

4. A system for improving the traction between a road surface and a motor vehicle including front and rear axles, one said axle being driven, four wheels mounted on said axles, and a roll stabilizer system having a plurality of actuating drives and operatively connected to said axles, and for reducing a stopping distance of the vehicle along the road surface, said system comprising:

a plurality of sensors, the coefficient of friction between each wheel and a road surface being measured by said sensors; and

a comparator connected to said plurality of sensors, the measured coefficients of friction being compared by said comparator, said comparator connected to each said actuating drive;

wherein a said front and a said rear axle are diagonally tensioned by said actuating drives and the wheel contact forces of two diagonally opposite wheels are one of increased and decreased in response to differences in measured coefficients of friction.

5. The system according to claim 4, wherein said comparator comprises a process computer.

6. The system according to claim 5, wherein at least a pair of said wheels are steered wheels having a variable steering angle, and further comprising an automatic steering system connected to said pair of steered wheels, the steering angle of said steered wheels being adjusted by said automatic steering system to offset a yaw movement of said vehicle generated by a greater deceleration of a wheel with substantially the highest coefficient of friction.

7. The system according to claim 6 wherein the steering angle is adjusted by said automatic steering system substantially simultaneously with said front and rear axles being diagonally tensioned by said actuating drives.