Traction control system for motor vehicle

• US 5,636,121 A
• Filed: 12/21/1994
• Issued: 06/03/1997
• Est. Priority Date: 12/28/1993
• Status: Expired due to Fees

• Current Assignee: Mazda Motor Corporation
• Original Assignee: Mazda Motor Corporation
• Inventors: Fukumoto, Yoshinori, Tsuyama, Toshiaki, Yoshida, Sotetsu, Nakamoto, Yoshihisa
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/360,559
• Time in Patent Office: 895 Days
• Field of Search: 364/426.03, 364/426.01, 364/424.05, 180/197, 180/140, 180/141, 180/142, 303/139, 303/140, 303/146
• US Class Current: 701/70
• CPC Class Codes: B60T 2210/14 Rough roads, bad roads, gravel roads
• CPC Class Codes: B60T 2260/022 Rear-wheel steering; Four-wheel steering
• CPC Class Codes: B60T 2260/024 Yawing moment compensation during mu-split braking
• 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
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B62D 7/159 characterised by computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition

Abstract

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.

Claims

1. A traction control system for a motor vehicle comprising:

steering characteristic control means 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;

driven torque control means for controlling driven torque applied to a driven wheel while a slip is generated in the driven wheel; and

driven torque correction means for correcting the driven torque so as to decrease as a wheel steering angle increases while said yaw rate difference stays within a particular range and said steering characteristic control means is operated.

2. A traction control system for a motor vehicle comprising:

steering characteristic control means 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;

driven torque control means for controlling driven torque applied to a driven wheel while a slip is generated in the driven wheel; and

driven torque correction means for correcting the driven torque so as to decrease as both the yaw rate difference and a wheel steering angle increase while said steering characteristic control means is operated.

3. A traction control system according to claim 2, wherein said driven torque correction means controls a correction by which the driven torque is decreased when both the wheel steering angle and the yaw rate difference are no greater than predetermined values.

4. A traction control system according to claim 2, wherein said driven torque correction means prohibits the driven torque from being corrected so as to decrease when both the wheel steering angle and the yaw rate difference are no greater than predetermined values.

5. A traction control system for a motor vehicle comprising:

steering characteristic control means 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;

target slip value providing means for providing a target slip value in a driven wheel;

driven torque control means for controlling driven torque applied to the driven wheel so that a slip in the driven wheel becomes equal to the target slip value while the slip is generated in the driven wheel; and

target slip value correction means for weighting a wheel steering angle and the yaw rate difference and correcting the target slip value so that it decreases as the wheel steering angle and the yaw rate difference are more heavily weighted while said steering characteristic control means is operated.

6. A traction control system according to claim 5, wherein said target slip value correction means weights the wheel steering angle more than the yaw rate difference.

7. A traction control system for a motor vehicle comprising:

steering characteristic control means 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;

target slip value providing means for providing a target slip value in a driven wheel;

driven torque control means for controlling driven torque applied to the driven wheel so that a slip in the driven wheel becomes equal to the target slip value while the slip is generated in the driven wheel; and

target slip value correction means for correcting the target slip value so that it decreases as the yaw rate difference increases while said steering characteristic control means is operated.

8. A traction control system for a motor vehicle comprising:

steering characteristic control means 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;

target slip value providing means for providing a target slip value in a driven wheel;

driven torque control means for controlling driven torque applied to the driven wheel so that a slip in the driven wheel becomes equal to the target slip value while the slip is generated in the driven wheel; and

target slip value correction means for correcting the target slip value so that it decreases as a wheel steering angle increases while said steering characteristic control means is operated.

9. A traction control system for a motor vehicle comprising:

steering characteristic control means 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;

driven torque control means for controlling driven torque applied to a driven wheel while a slip is generated in the driven wheel;

rough road determination means for determining a rough road;

rough road correction means for correcting the driven torque so that the vehicle becomes stable when the rough road is determined; and

rough road correction changing means for changing the corrected driven torque so that it decreases when the rough road is determined and both a wheel steering angle and the yaw rate difference are no less than predetermined values while said steering characteristic control means is operated.

10. A slip control system according to claim 9, wherein said rough road correction means increases the driven torque so that the vehicle is accelerated.

11. A slip control system according to claim 9, wherein said rough road correction means decreases the driven torque so that the vehicle is decelerated.

12. A traction control system for a motor vehicle comprising:

steering characteristic control means 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;

driven torque control means for controlling driven torque applied to a driven wheel while a slip is generated in the driven wheel;

rough road determination means for determining a rough road;

rough road correction means for correcting the driven torque so that the vehicle becomes stable when the rough road is determined; and

rough road correction changing means for changing the corrected driven torque so that it decreases as a wheel steering angle increases while said steering characteristic control means is operated when the rough road is determined.

13. A slip control system according to claim 12, wherein said rough road correction means increases the driven torque so that the vehicle is accelerated.

14. A slip control system according to claim 12, wherein said rough road correction means decreases the driven torque so that the vehicle is decelerated.

15. A traction control system for a motor vehicle comprising:

steering characteristic control means 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;

driven torque control means for controlling driven torque applied to a driven wheel while a slip is generated in the driven wheel;

rough road determination means for determining a rough road;

rough road correction means for correcting the driven torque so that the vehicle becomes stable when the rough road is determined; and

rough road correction changing means for decreasing the corrected driven torque as the yaw rate difference increases while said steering characteristic control means is operated when the rough road is determined.

16. A slip control system according to claim 15, wherein said rough road correction means increases the driven torque so that the vehicle is accelerated.

17. A slip control system according to claim 15, wherein said rough road correction means decreases the driven torque so that the vehicle is decelerated.