Method to Reduce the Turn Radius of Motor Vehicles Utilizing Automatic Single Side Rear Brake Application

• US 20070267916A1
• Filed: 05/18/2006
• Published: 11/22/2007
• Est. Priority Date: 05/18/2006
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Kennedy, Mario B., Mackovjak, John M., Nisonger, Robert L.
• Granted Patent: US 7,712,845 B2
• Time in Patent Office: Days
• US Class Current: 303/146
• CPC Class Codes: B60T 11/21 with two pedals operating on respective circuits, pressures therein being equalised when both pedals are operated together, e.g. for steering steering non-deflectable wheels or endless tracks by differentially driving ground-engaging elements on opposite vehicle sides using brakes as main steering effecting means B62D11/08
• CPC Class Codes: B60T 2201/16 Curve braking control, e.g. turn control within ABS control algorithm
• 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: B60T 8/246 Change of direction
• CPC Class Codes: B62D 11/003 Electric or electronic control systems
• CPC Class Codes: B62D 11/08 using brakes or clutches as main steering-effecting means
• CPC Class Codes: B62D 11/24 Endless track steering specially adapted for vehicles having both steerable wheels and endless track

Abstract

A method of selective, automatic application of one rear brake of a motor vehicle under appropriate vehicle operating conditions in response to intent of a driver to make a turn, whereby the rotational speed of the selected braked rear wheel is reduced so as to reduce the turn radius of the vehicle. Vehicle sensor outputs and calculated parameters in conjunction with vehicle systems such as, but not limited to, ESC, ABS, and traction control are used to determine if appropriate vehicle operating conditions exist to actuate the present invention. The method of the present invention is implemented via an algorithmic control, preferably within an ESC system.

Claims

1. A method for reducing motor vehicle turning radii, said method comprising the steps of:

sensing a turn of a motor vehicle;

determining which rear wheel of the motor vehicle is an inside rear wheel of the turn; and

selectively applying a brake of the inside rear wheel in automatic response to said step of sensing to thereby effect a reduction in turning radius of the turn of the motor vehicle.

2. The method of claim 1, wherein said step of selectively applying the brake comprises:

determining wheel slip of the inside rear wheel; and

applying brake pressure to the brake within a predetermined brake pressure range so that the wheel slip is within a predetermined wheel slip range.

3. The method of claim 2, wherein said step of selectively applying the brake comprises:

determining preselected operating conditions of the motor vehicle; and

applying the brake only if the determined preselected operating conditions are within preselected ranges.

4. The method of claim 3, wherein said preselected operating conditions are selected from a group comprising:

a brake pedal pressure less than a predetermined pressure;

an absence of chassis control activity;

engine running;

time in a selected gear is greater than a predetermined gear time;

steering wheel angular position exceeds a predetermined steering wheel angular position;

vehicle speed is within a predetermined range of vehicle speed; and

throttle position is within a predetermined throttle range.

5. The method of claim 4, wherein said chassis control activity comprises:

an electronic control of the motor vehicle sensing a tracking instability for which the electronic control provides a pre-programmed stability control response.

6. The method of claim 3, wherein the determining of preselected operating conditions of the motor vehicle comprises:

determining that a brake pedal pressure is less than a predetermined pressure;

determining that chassis control activity is absent;

determining that the engine of the motor vehicle is running;

determining that the time in a selected gear is greater than a predetermined gear time;

determining that the steering wheel of the motor vehicle has an angular position exceeding a predetermined steering wheel angular position;

determining that speed of the motor vehicle is within a predetermined range of vehicle speed; and

determining that position of a throttle of the motor vehicle is within a predetermined throttle range.

7. The method of claim 6, wherein said chassis control activity comprises:

an electronic control of the motor vehicle sensing a tracking instability for which the electronic control provides a pre-programmed stability control response.

8. The method of claim 1, wherein said step of sensing comprises sensing a turn of the motor vehicle in which a steering wheel of the motor vehicle has been rotated to an angular position that is within a range of substantially between 95 percent and 98 percent of a maximum angular position thereof.

9. The method of claim 8, wherein said predetermined wheel slip range is substantially between 1 percent and 70 percent.

10. The method of claim 9, wherein the determining of preselected operating conditions of the motor vehicle comprises:

determining that a brake pedal pressure is less than a predetermined pressure;

determining that chassis control activity is absent;

determining that the engine of the motor vehicle is running;

determining that the time in a selected gear is greater than a predetermined gear time;

determining that the steering wheel of the motor vehicle has an angular position exceeding a predetermined steering wheel angular position;

determining that speed of the motor vehicle is within a predetermined range of vehicle speed; and

determining that position of a throttle of the motor vehicle is within a predetermined throttle range.

11. The method of claim 10, wherein said chassis control activity comprises:

an electronic control of the motor vehicle sensing a tracking instability for which the electronic control provides a pre-programmed stability control response.

12. A method for reducing motor vehicle turning radii, comprising the steps of:

sensing a turn of a motor vehicle;

determining which rear wheel of the motor vehicle is an inside rear wheel of the turn;

determining wheel slip of the inside rear wheel; and

selectively braking the inside rear wheel in automatic response to said step of sensing so that the wheel slip is within a predetermined wheel slip range which thereby effects a reduction in turning radius of the turn of the motor vehicle.

13. The method of claim 12, wherein said step of selectively braking comprises:

determining selected conditions of the motor vehicle;

selectively braking the wheel in response to an electrical output of an electronic controller, wherein the electrical output is responsive to the determined selected conditions of the motor vehicle.

14. The method of claim 13, wherein said step of selectively braking comprises the electronic controller determining a plurality of vehicle conditions comprising:

determining that a brake pedal pressure is less than a predetermined pressure;

determining that chassis control activity is absent;

determining that the engine of the motor vehicle is running;

determining that the time in a selected gear is greater than a predetermined gear time;

determining that the steering wheel of the motor vehicle has an angular position exceeding a predetermined steering wheel angular position;

determining that speed of the motor vehicle is within a predetermined range of vehicle speed; and

determining that position of a throttle of the motor vehicle is within a predetermined throttle range.

15. The method of claim 14, wherein said chassis control activity comprises:

an electronic control of the motor vehicle sensing a tracking instability for which the electronic control provides a pre-programmed stability control response.

16. The method of claim 13, wherein said step of sensing comprises sensing a turn of the motor vehicle in which a steering wheel of the motor vehicle has been rotated to an angular position that is within a range of substantially between 95 percent and 98 percent of a maximum angular position thereof.

17. The method of claim 16, wherein said predetermined wheel slip range is substantially between 1 percent and 70 percent.

18. The method of claim 17, wherein the determining of preselected operating conditions of the motor vehicle comprises:

determining that a brake pedal pressure is less than a predetermined pressure;

determining that chassis control activity is absent;

determining that the engine of the motor vehicle is running;

determining that the time in a selected gear is greater than a predetermined gear time;

determining that the steering wheel of the motor vehicle has an angular position exceeding a predetermined steering wheel angular position;

determining that speed of the motor vehicle is within a predetermined range of vehicle speed; and

determining that position of a throttle of the motor vehicle is within a predetermined throttle range.

19. The method of claim 18, wherein said chassis control activity comprises:

an electronic control of the motor vehicle sensing a tracking instability for which the electronic control provides a pre-programmed stability control response.