Methods and systems for automated control of vehicle braking

• US 8,027,773 B2
• Filed: 08/10/2007
• Issued: 09/27/2011
• Est. Priority Date: 08/10/2007
• Status: Active Grant

• Current Assignee: Toyota Motor Corporation
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: Ahn, Samuel S.
• Primary Examiner(s): Chen; Shelley
• Application Number:
  US11/891,427
• Publication Number:
  US 20090043470A1
• Time in Patent Office: 1,509 Days
• Field of Search: 701/70
• US Class Current: 701/70
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 40/09 Driving style or behaviour

Abstract

Method and systems for automated anticipatory braking of a vehicle are provided. In one embodiment, the system comprises a vehicle accelerator movable between a maximum speed position and a minimum speed position, and a sensor configured to determine the rate of travel of the accelerator toward the minimum speed position. The system further comprises a controller configured to utilize the rate of travel of the accelerator to determine if a rapid braking condition is desired, and to provide a control signal to apply increased negative torque to the drive wheels of the vehicle prior to the user applying the vehicle brake. In some embodiments, driver history and/or other vehicle conditions are taken into account. In some embodiments, negative torque is applied via varying of valve timing, control of combustion chamber intake, control of exhaust backpressure, control of motor energy, and/or shifting of a transmission to a numerically higher speed ratio.

Claims

1. A method for automated braking of a vehicle, comprising:

monitoring at least two of a road grade condition, a wet road condition or a road obstacle condition with sensors;

monitoring the rate of travel of an accelerator pedal in a deceleration direction;

determining if the rate of travel surpasses a threshold level;

if the threshold level is surpassed, determining if at least two vehicle conditions are present with the sensors, wherein the at least two vehicle conditions are at least two of a road grade condition, a wet road condition, a road obstacle condition or combinations thereof; and

if the threshold is surpassed and at least two vehicle conditions are present, braking the motor vehicle by controlling the negative torque on the drive wheels.

2. The method as recited in claim 1, wherein the negative torque on the drive wheels is controlled by varying the timing of intake and exhaust valves in an internal combustion engine.

3. The method as recited in claim 1, wherein the negative torque on the drive wheels is controlled by varying the amount of energy generated per revolution of an electric motor/generator.

4. The method as recited in claim 1, wherein the negative torque on the drive wheels is controlled by moving a transmission to a numerically higher speed ratio.

5. The method as recited in claim 1, wherein the rate of travel is monitored by sensing the positions of an accelerator pedal between points in time and calculating the rate based upon the positions.

6. The method as recited in claim 1, wherein an electronic controller carries out the determining and braking operations.

10. The method of claim 1 wherein the road grade condition is present when a grade of the road is greater than a pre-determined grade.

11. The method of claim 10 wherein the pre-determined grade is 5%.

12. The method of claim 1 wherein the road obstacle condition is present when a distance between the vehicle and an object detected in the path of the vehicle is greater than 1.5 times a stopping distance of the vehicle under maximum braking at a current speed of the vehicle.

7. A system for automated braking of a vehicle, comprising:

an accelerator position sensor configured to determine the rate of movement of a driver accelerator;

at least two sensors configured to determine if certain vehicle conditions are present, wherein the vehicle conditions are at least two of a road grade condition, a wet road condition, a road obstacle condition or combinations thereof;

a controller in communication with the accelerator position sensor and the at least two sensors, wherein the controller is programmed to;

determine if the vehicle conditions are present with the at least two sensors when the rate of movement of the driver accelerator surpasses a predetermined threshold in a decreased speed direction of the driver accelerator; and

generate a control signal configured to apply negative torque to the drive wheels of the vehicle when the rate of movement of the driver accelerator surpasses a predetermined threshold in a decreased speed direction of the driver accelerator and at least two of the vehicle conditions are present.

8. The system as recited in claim 7, wherein the controller and the accelerator position sensor are integral.

9. The system as recited in claim 7, wherein the control signal comprises at least one of an intake valve control signal, an exhaust valve control signal, a motor control signal, and a transmission control signal.

13. The system of claim 7 wherein the at least two sensors include an obstacle sensor.

14. The system of claim 13 wherein the obstacle sensor is configured to determine when a distance between the vehicle and an object detected in the path of the vehicle is greater than 1.5 times a stopping distance of the vehicle under maximum braking at a current speed of the vehicle.

15. The system of claim 7 wherein the at least two sensors include a road grade sensor configured to determine if a grade of the road is greater than a pre-determined grade.

16. The system of claim 7 further comprising a vehicle component operatively coupled to the controller, wherein the vehicle component receives the control signal from the controller and affects the torque on the drive wheels based on the control signal received from the controller.

17. The system of claim 16 wherein the vehicle component comprises an internal combustion engine, and wherein the control signal controls the timing of intake and exhaust valves of the internal combustion engine.

18. The system of claim 16 wherein the vehicle component comprises a valve in an exhaust path of the vehicle for controlling a backpressure of exhaust and the control signal controls a position of the valve.

19. The system of claim 16 wherein the vehicle component comprises a transmission of the vehicle and the control signal shifts the transmission to a numerically higher speed ratio.

20. The system of claim 16 wherein the vehicle component comprises a motor/generator coupled to a drive shaft and the control signal controls an amount of energy generated per revolution of the drive shaft.