Vehicle brake control apparatus for controlling normal wheel brakes upon detection of defective wheel brake or brakes

• US 20020109403A1
• Filed: 04/23/2002
• Published: 08/15/2002
• Est. Priority Date: 09/21/1999
• Status: Active Grant

• Current Assignee: Advics Company Limited (Aisin Corp.)
• Original Assignee: Hiroaki Aizawa, Naoki Sawada, Seiichi Kojima, Takayuki Yamamoto
• Inventors: Aizawa, Hiroaki, Yamamoto, Takayuki, Sawada, Naoki, Kojima, Seiichi
• Granted Patent: US 6,902,241 B2
• Time in Patent Office: Days
• US Class Current: 303/146
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 17/18 Safety devices; Monitoring
• CPC Class Codes: B60T 2270/402 Back-up
• CPC Class Codes: B60T 2270/613 ESP features related thereto
• CPC Class Codes: B60T 8/00 Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force by changing number of effective brake cylinders in power brake systems B60T17/10
• 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: B60T 8/24 responsive to vehicle inclination or change of direction, e.g. negotiating bends using electrical circuitry or regulation means B60T8/17
• CPC Class Codes: B60T 8/246 Change of direction
• CPC Class Codes: B60T 8/885 using electrical circuitry
• CPC Class Codes: B60T 8/92 automatically taking corrective action

Abstract

A brake control apparatus for controlling at least three brake devices provided for braking respective at least three wheels of an automotive vehicle which includes two wheels located on respective left and right sides of the vehicle, wherein an emergency brake control portion is provided for controlling at least two normal brake devices when at least one of the at least three brake devices is defective, such that a difference between a total left-side braking force to be generated by at least one normal brake device located on the left side of the vehicle and a total right-side braking force to be generated by the other normal brake device or devices located on the right side is made larger when operations of all of the normal brake devices in a detected running condition of the vehicle are not likely to deteriorate the vehicle running stability, than when the operations of all of the normal brake devices in the detected running condition are likely to deteriorate the vehicle running stability.

Claims

1. A brake control apparatus for controlling at least three brake devices provided for braking respective at least three wheels of an automotive vehicle which includes two wheels located on respective left and right sides of the vehicle, said brake control apparatus comprising:

an emergency brake control portion for controlling at least two normal brake devices of said at least three brake devices when at least one of said at least three brake devices is defective, such that a difference between a total left-side braking force to be generated by at least one of said at least two normal brake devices which is located on the left side of the vehicle and a total right-side braking force to be generated by the other of said at least two normal brake devices which is located on the right side of the vehicle is made larger when operations of all of said at least two normal brake devices in a detected running condition of the vehicle are not likely to deteriorate a running stability of the vehicle, than when the operations of all of said at least two normal brake devices in said detected running condition are likely to deteriorate the running stability of the vehicle.

2. A brake control apparatus according to claim 1, wherein said emergency brake control portion includes a running-condition detecting portion for effecting a determination as whether the operations of all of said at least two normal brake devices in said detected running condition of the vehicle are likely to deteriorate the running stability of the vehicle or not, on the basis of at least one of a detected running speed and a detected steering state of the vehicle.

3. A brake control apparatus according to claim 2, wherein said running-condition detecting portion determines that the operations of all of said at least two normal brake devices in said detected running condition of the vehicle are not likely to deteriorate the running stability of the vehicle, when said detected running speed is lower than a predetermined threshold determined by said detected steering state of the vehicle.

4. A brake control apparatus according to claim 1, wherein said emergency brake control portion includes a turning-direction-based running-condition detecting portion for detecting a determination as to whether the operations of all of said at least two normal brake devices in said detected running condition of the vehicle are likely to deteriorate the running stability of the vehicle, on the basis of a location of each of said at least one defective brake device on the vehicle and a detected direction of turning of the vehicle.

5. A brake control apparatus according to claim 4, wherein said turning-direction-based running-condition detecting portion determines that the operations of all of said at least two normal brake devices in said detected running condition are not likely to deteriorate the running stability of the vehicle when said at least one defective brake device includes a brake device provided for one of said at least three wheels which is located on an inner side of a path of turning of the vehicle in said detected direction.

6. A brake control apparatus according to claim 1, wherein said emergency brake control portion determines that the vehicle has a higher degree of running stability when the number of said at least one defective brake device is relatively small than when said number is relatively large.

7. A brake control apparatus according to claim 1, wherein said emergency brake control portion controls a braking force to be generated by each of at least one of said at least two normal brake devices, on the basis of said detected running condition of the vehicle.

8. A brake control apparatus according to claim 1, wherein said emergency brake control portion includes a change-rate restricting portion for controlling at least one of a rate of increase and a rate of reduction of a braking force to be generated by each of at least one of said at least two normal brake devices, such that each of said at least one of said rates of increase and reduction is lower when at least one of said at least three brake devices is found defective than when none of said at least three brake devices is found defective.

9. A brake control apparatus according to claim 1, wherein said emergency brake control portion includes a change-rate restricting portion for controlling at least one of a rate of increase and a rate of reduction of a braking force to be generated by each of at least one of said at least two normal brake devices, such that each of said at least one of said rates of increase and reduction is lower when normal operations of all of said at least two normal brake devices in said detecting running condition of the vehicle are likely to increase said difference between said total left-side braking force and said total right-side braking force, than when said normal operations are not like to increase said difference.

11. A brake control apparatus according to claim 1,wherein each of said brake devices includes a friction member movably supported by a body of said automotive vehicle, and an electrically operated actuator operable to force said friction member against a rotor rotating with a corresponding one of said wheels, said electrically operated actuator being operated with an electric energy to be supplied thereto such that a force by which said friction member is forced against said rotor by said actuator is controllable by controlling an amount of said electric energy.

14. A brake control apparatus according to claim 13, wherein said emergency brake control portion operates all of said. at least one normal brake device when said detected running speed of the vehicle is lower than a predetermined threshold, and inhibits an operation of at least one of said at least one normal brake device when said detected running speed is not lower than said predetermined threshold.

15. A brake control apparatus according to claim 12, wherein said emergency brake control portion includes a first braking-force restricting portion for controlling a braking force to be generated by each of said at least one of said at least one normal brake device such that said braking force is smaller when said detected running speed of the vehicle is higher than a predetermined threshold than when the detected running speed is not higher than said predetermined threshold.

16. A brake control apparatus according to claim 14, wherein said emergency brake control portion includes a second braking-force restricting portion for determining said threshold value such that said threshold value is smaller when the number of said at least one defective brake device is relatively large than when said number is relatively small.

17. A brake control apparatus according to claim 15, wherein said emergency brake control portion includes a second braking-force restricting portion for determining said threshold value such that said threshold value is smaller when the number of said at least one defective brake device is relatively large than when said number is relatively small.

19. A brake control apparatus according to claim 18, wherein said emergency brake control portion includes a third braking-force restricting portion for controlling at least one of said at least one normal brake device which is located on one of opposite sides of the vehicle which is opposite to the other side on which one of said at least one defective brake device is located, such that a braking force to be generated by each of said at least one of said at least one normal brake device located on said one of opposite sides of the vehicle is made smaller when said one of said at least one defective brake device which is located on said other side of the vehicle is located on an outer side of a path of turning of the vehicle than when said one of said at least one defective vehicle is located on an inner side of said path of turning of the vehicle.

20. A brake control apparatus according to claim 19, wherein said third braking-force restricting portion controls said braking force to be generated by said each of said at least one of said at least one normal brake device such that the braking force is smaller when a detected steering angle of the vehicle is relatively large than when said detected steering angle is relatively small.

21. A brake control apparatus according to claim 18, wherein said emergency brake control portion further includes a running-speed-based brake control portion for controlling the braking force to be generated by said each of at least one of said at least one normal brake device, on the basis of a detected running speed of the vehicle.

10. A brake control apparatus for controlling a plurality of brake devices for braking respective wheels of an automotive vehicle, said brake control apparatus comprising:

a change-rate restricting portion is provided for restricting at least one of a rate of increase and rate of reduction of a barking force to be generated by each of at least one of at least one normal brake device of said plurality of brake devices, when at least one of said plurality of brake devices is found defective, such that each of said at least one of said rates of increase and reduction is lower when said at least one of said at least three brake devices is found defective than when none of said plurality of brake devices is found defective.

12. A brake control apparatus according to claim 10, wherein each of said brake devices includes a friction member movably supported by a body of said automotive vehicle, and an electrically operated actuator operable to force said friction member against a rotor rotating with a corresponding one of said wheels, said electrically operated actuator being operated with an electric energy to be supplied thereto such that a force by which said friction member is forced against said rotor by said actuator is controllable by controlling an amount of said electric energy.

13. A brake control apparatus for controlling a plurality of brake devices for braking respective wheels of an automotive vehicle, said brake control apparatus comprising:

an emergency brake control portion is provided for controlling at least one normal brake device of said plurality of brake devices when at least one of said plurality of brake device is defective, such that a braking force to be generated by each of at least one of said at least one normal brake device is controlled on the basis of a detected running speed of the vehicle.

18. A brake control apparatus for controlling a plurality of brake devices for braking respective wheels of an automotive vehicle, comprising;

an emergency brake control portion is provided for controlling at least one normal brake device of said plurality of brake devices when at least one of said plurality of brake devices is defective, such that a braking force to be generated by each of at least one of said at least one normal brake device is controlled on the basis of a detected steering state of the vehicle.

22. A brake control apparatus for controlling a plurality of primary brake devices for braking respective wheels of an automotive vehicle, and at least one secondary brake device provided for at least one of said wheels, respectively, said brake control apparatus comprising:

an emergency brake control portion operable when at least one of said plurality of primary brake devices is defective, for operating at least one of said at least one secondary brake device which corresponds to at least one of said at least one defective primary brake device.

23. A brake control apparatus according to claim 22, wherein said emergency brake control portion includes an emergency primary-braking-force control portion for controlling a braking force to be generated by each of at least one normal primary brake device of said plurality of primary brake devices, so that a running stability of the vehicle as represented by a detected running condition of the vehicle is higher than a predetermined threshold.

24. A brake control apparatus according to claim 23, wherein said emergency primary-braking-force control portion controls the braking force to be generated by each of said at least one normal primary brake device, on the basis of said detected running condition of the vehicle.

25. A brake control apparatus according to claim 22, wherein said emergency brake control portion includes a braking-force-difference reducing type brake control portion for controlling at least one of braking forces to be generated by said primary and secondary brake devices which are normal, such that a difference between a total left-side braking force to be generated by all of at least one of the primary and secondary brake devices that is located on a left side of the vehicle and a total right-side braking force to be generated by all of the other of the primary and secondary brake devices that is located on a right side of the vehicle will not exceed than a predetermined threshold.

26. A brake control apparatus according to claim 25, wherein said braking-force-difference reducing type control portion includes a primary-braking-force restricting portion for operating all of said at least one secondary brake device that corresponds to all of said at least one defective primary brake device, and restricting the braking force to be generated by each of at least one of normal ones of said primary brake devices.

27. A brake control apparatus according to claim 26 wherein said primary-braking-force restricting portion restricts the braking force to be generated by each of said at least one normal primary brake device, when a running stability of the vehicle as represented by a detected running condition of the vehicle is lower than a predetermined threshold.

28. A brake control apparatus according to claim 22, wherein said emergency brake control portion includes a braking-force reduction restricting control portion for controlling at least one of braking forces to be generated by said primary and second brake devices, so that a total braking force to be applied to the vehicle is not smaller than a desired braking force value as represented by an amount of operation of a brake operating member by an operator of the vehicle.

29. A brake control apparatus according to claim 22, wherein said at least one secondary brake device consists of a plurality of secondary brake devices which are provided for said wheels, respectively, and which correspond to said plurality of primary brake devices, respectively, said primary and secondary brake devices for each of said wheels are connected to respective different power sources.