Active cancellation of brake torque variation

Patent metadata

Field	Value
Publication number	US-10647305-B2
Application number	US-201514631490-A
Country	US
Kind code	B2
Filing date	Feb 25, 2015
Priority date	Feb 25, 2015
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

Systems and methods for cancelling brake torque variation in a motor vehicle are disclosed. Signals indicative of brake torque variation are received at a controller. Based on the signals, a frequency associated with the indicated brake torque variation is determined. At least one of an output time and output volume of pressurized brake fluid is adjusted based on the frequency to cancel the indicated brake torque variation.

First claim

What is claimed is:

1. A method for cancelling brake torque variation, comprising:
controlling, via a controller, an antilock brake system (“ABS”) brake pedal valve fluidly coupled to a reservoir, the ABS brake pedal valve controlling delivery of pressurized brake fluid from a master cylinder to brake calipers;
receiving, at the controller, signals indicative of brake torque variation;
determining, based on the signals, a frequency of the brake torque variation;
bypassing, via the controller, control of the ABS brake pedal valve, by controlling, via the controller, a brake valve and a pump motor; and
in response to controlling the brake valve and pump motor, calculating an output volume of pressurized fluid to be applied to calipers of the brake system, and reducing the brake torque variation by delivering the calculated output volume of pressurized brake fluid from an accumulator fluidly coupled to a pump and the brake valve to the calipers of the brake system by controlling the pump motor based on the frequency.

2. The method of claim 1 , further comprising identifying a pattern of axial thickness on disc brake rotor causing the brake torque variation.

3. The method of claim 1 , further comprising increasing the output volume of the pressurized brake fluid as a thin portion of a disc brake rotor passes through the calipers.

4. The method of claim 3 , further comprising decreasing the output volume of the pressurized brake fluid as a thick portion of the disc brake rotor passes through the calipers.

5. The method of claim 3 , wherein the frequency and phase of the brake torque variation is detected using a tuned resonator whose resonant frequency is based on vehicle speed.

6. The method of claim 1 , further comprising compensating for brake torque variation at each wheel of a motor vehicle.

7. The method of claim 1 , wherein delivering pressurized brake fluid to calipers of the brake system by controlling the pump motor based on the frequency comprises opening, via the controller, the brake valve and a pressure control valve to direct pressurized brake fluid to the accumulator.

8. The method of claim 1 , wherein delivering pressurized brake fluid to the calipers by controlling a pump motor based on the frequency comprises adjusting at least one of an output time and output volume of pressurized brake fluid directed from the pump to the calipers.

9. The method of claim 1 , wherein delivering pressurized brake fluid to the calipers by controlling the pump motor based on the frequency cancels the brake torque variation.

10. The method of claim 1 , wherein delivering pressurized brake fluid to the calipers by controlling the pump motor based on the frequency reduces a variation in a clamping force applied to a rotor of the brake system via the calipers.

11. A system for cancelling brake torque variation, comprising:
a master cylinder;
a pump;
a motor configured to drive the pump;
an accumulator fluidly coupled to the pump;
a brake valve disposed between and in fluid connection with the master cylinder and the accumulator;
antilock brake system (“ABS”) brake pedal valves coupled to and in fluid communication with the master cylinder and a reservoir; and
a controller configured to:
receive signals indicative of brake torque variation;
determine, based on the signals, a frequency and a phase associated with the indicated brake torque variation;
calculate an output volume of pressurized fluid to be applied to calipers;
control the motor based on at least one of the frequency and the phase to deliver the calculated output volume of pressurized brake fluid from the accumulator to the calipers via the pump to move brake pads into contact with a disc brake rotor, thereby bypassing ABS brake pedal valves control of pressurized brake fluid from the master cylinder and reducing the brake torque variation.

12. The system of claim 11 , wherein the controller is further configured to identify a pattern of axial wear on the disc brake rotor causing the brake torque variation.

13. The system of claim 11 , wherein the output volume of the pressurized brake fluid is increased when a thin portion of the disc brake rotor passes through the calipers.

14. The system of claim 13 , wherein the output volume of the pressurized brake fluid is decreased when a thick portion of the disc brake rotor passes through the calipers.

15. The system of claim 11 , wherein brake torque variation is mitigated at each wheel of a motor vehicle.

16. The system of claim 11 , wherein the accumulator and brake valve are configured to hydraulically isolate the pump from the master cylinder.

17. The system of claim 11 , wherein delivering pressurized brake fluid by controlling a pump motor based on the frequency comprises adjusting at least one of an output time and output volume of pressurized brake fluid directed from a pump to calipers.

18. The system of claim 11 , wherein delivering pressurized brake fluid by controlling a pump motor based on the frequency comprises canceling the brake torque variation.

19. A method for cancelling brake torque variation in a brake system, the method comprising:
controlling the brake system via an antilock brake system (“ABS”) brake pedal valve fluidly coupled to a reservoir;
receiving, at a controller, signals indicative of brake torque variation;
determining, based on the signals, a frequency of the brake torque variation;
calculating an output volume of pressurized fluid to be applied to calipers causing brake pads to apply a clamping force on a rotor of the brake system; and

reducing the brake torque variation by delivering the calculated volume of pressurized brake fluid from an accumulator fluidly coupled to a pump and the brake valve to the calipers of the brake system, while bypassing the ABS brake pedal valve control of the brake system via the controller by opening a brake valve and controlling a pump motor, based on the frequency.

20. The method of claim 19 , wherein controlling a hydraulic fluid volume includes adding fluid to or releasing fluid from the calipers based on the frequency.

Assignees

• Ford Global Tech Llc

Inventors

• Johnson Bradley J
• Crombez Dale Scott
• Joyce John P
• Gamberg Eric M

Classifications

• B60T13/66 Primary

  Electrical control in fluid-pressure brake systems · CPC title

• B60T8/17 Primary

  Using electrical or electronic regulation means to control braking {(detecting or indicating faulty operation B60T8/885)} · CPC title

• B60T8/173 Primary

  Eliminating or reducing the effect of unwanted signals, e.g. due to vibrations or electrical noise · CPC title