System And Method To Control Regenerative Braking

• US 20110233994A1
• Filed: 03/29/2010
• Published: 09/29/2011
• Est. Priority Date: 03/29/2010
• Status: Active Grant

• Current Assignee: Current Motor Co.
• Original Assignee: Electric Vehicle Manufacturing, LLC
• Inventors: Harding, John, Kauppi, Erik
• Granted Patent: US 9,434,362 B2
• Time in Patent Office: Days
• US Class Current: 303/152
• CPC Class Codes: B60L 2200/12 Bikes
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B60T 1/10 by utilising wheel movement for accumulating energy, e.g. driving air compressors
• CPC Class Codes: B60T 2270/604 Merging friction therewith; Adjusting their repartition
• CPC Class Codes: B60T 8/1706 for single-track vehicles, e.g. motorcycles
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 30/18127 Regenerative braking
• CPC Class Codes: B60Y 2200/12 Motorcycles, Trikes; Quads; Scooters

Abstract

A braking system for an electric vehicle has a first wheel having a first friction brake and an electric motor and a second having a second friction brake. A first user-actuated brake lever is coupled to the first friction brake. The first brake lever has a first sensor indicating actuation of the first brake lever. A second user-actuated brake lever is coupled to the second friction brake. The second brake lever has a second sensor indicating actuation of the second brake lever. An electronic control unit electronically coupled to the first and second sensors and the electric motor commands the electric motor to operate as a generator when at least one of the brake levers is actuated.

Claims

1. A braking system for an electric vehicle, comprising:

a first wheel coupled to the electric vehicle, the first wheel having a first friction brake and an electric motor;

a second wheel coupled to the electric vehicle, the second wheel having a second friction brake;

a first user-actuated brake lever coupled to the first friction brake, the first brake lever having a first sensor indicating actuation of the first brake lever;

a second user-actuated brake lever coupled to the second friction brake, the second brake lever having a second sensor indicating actuation of the second brake lever; and

an electronic control unit electronically coupled to the first and second sensors and the electric motor.

2. The braking system of claim 1 wherein the electronic control unit causes the electric motor to generate electricity based on a signal from at least one of the first and second sensors indicating that at least one of the first and second brake levers has been actuated.

3. The braking system of claim 1, further comprising:

a first spring biasing the first brake lever to an unactuated position; and

a second spring biasing the second brake lever to an unactuated position wherein the first sensor is a two-position switch with a first position indicating that the first brake lever is in the unactuated position and a second position indicating that the first brake lever is being actuated.

4. The braking system of claim 1 wherein the first sensor provides a first signal indicating travel of the first brake lever and the second sensor provides a second signal indicating travel of the second brake lever.

5. The braking system of claim 4 wherein the electronic control unit commands the electric motor to generate electricity in an amount which increases monotonically based on the first and second signals.

6. The braking system of claim 1 wherein the second sensor provides a signal indicating travel of the second brake lever and the electronic control unit commands the electric motor to generate electricity in an amount which increases monotonically based on the signal.

7. The brake system of claim 1 wherein the first brake lever has:

an unactuated position;

a lower actuation range in which the electronic control unit commands the electric motor to generate electricity and the first friction brake is unactuated; and

a higher actuation range in which the electronic control unit commands the electric motor to generate electricity and the first friction brake is actuated.

8. The system of claim 1 wherein the electric motor coupled to the first wheel is a first electric motor, the system further comprising:

a second electric motor mechanically coupled to the second wheel and electronically coupled to the electronic control unit, the electronic control unit commanding the first and second electric motors to operate as generators when at least one of the first and second user-operated brake input devices is actuated.

9. The system of claim 8 wherein a first braking torque applied by the first motor is proportional with a second braking torque applied by the second motor.

10. The system of claim 8 wherein the motor coupled to the first wheel is a first motor, the system further comprising:

a second electric motor mechanically coupled to the second wheel and electronically coupled to the electronic control unit, the electronic control unit commanding the first electric motor to operate as a generator when the first user-operated brake input device is actuated and commanding the second electric motor to operate as a generator when the second user-operated brake input device is actuated.

11. The system of claim 10 wherein the first and second sensors indicate a travel of first and second user-operated brake input devices, respectively, and a braking torque commanded to the first motor is based on travel of the first user-operated brake input device and a braking torque commanded to the second motor is based on travel of the second user-operated brake input device.

12. The system of claim 8 wherein the first wheel is a rear wheel, the second wheel is a front wheel, and the motor is a rear motor, the system further comprising:

a front electric motor mechanically coupled to the front wheel and electronically coupled to the electronic control unit, the electronic control unit;

commanding the front electric motor to operated as a generator when at least one of the first user-operated brake input device and the second user-operated brake input device is actuated.

13. A braking system, comprising:

a first wheel;

a first friction brake coupled to the first wheel;

a second wheel;

a second friction brake coupled to the second wheel;

an electric motor coupled to the first wheel;

an electronic control unit electronically coupled to the electric motor;

a first user-operated brake input device coupled to the first brake;

a first sensor coupled to the first user-operated brake input device and electronically coupled to the electronic control unit;

a second user-operated brake input device coupled to the second brake; and

a second sensor coupled to the second user-operated brake input device and electronically coupled to the electronic control unit and the electronic control unit wherein the electronic control unit commands the electric motor to operate as a generator when at least one of the first and second user-operated brake input devices is actuated.

14. The system of claim 13 wherein:

the first user-operated brake input device is mechanically coupled to the first brake via at least one of a cable and a hydraulic line;

the second user-operated brake input device is mechanically coupled to the second brake via at least one of a cable and a hydraulic line;

the first user-operated brake input device is one of a hand lever and a foot pedal; and

the second user-operated brake input device is one of a hand lever and a foot pedal.

15. The system of claim 13 wherein the first sensor is a switch indicating whether the first input device is actuated and the electronic control unit commands the motor to generate electricity up to a first fraction of a maximum regeneration capacity of the motor when the first user-operated brake input device is actuated and the second user-actuated input device is unactuated.

16. The system of claim 15 wherein the second sensor is a switch indicating whether the second input device is actuated and the electronic control unit commands the motor to generate electricity up to a second fraction of the maximum regeneration capacity of the motor when the second user-operated brake input device is actuated and the first user-actuated input device is unactuated.

17. The system of claim 16 wherein the electronic control unit commands the motor to generate electricity at a third fraction of the maximum regeneration capacity of the motor when both the first and second user-operated brake input devices are actuated, the third fraction is greater than the first fraction, and the third fraction is greater than the second fraction.

18. The system of claim 13 wherein the first and second sensors are comprised of one of linear position sensors, rotary position sensors, and angular position sensors.

19. The system of claim 13 wherein the first sensor provides a first signal indicating travel of the first user-operated brake input device and the second sensor provides a second signal indicating travel of the second user-operated brake input device.

20. The system of claim 19 wherein the ECU commands the electric motor to generate an amount of electricity based on the first and second signals.

21. A method to brake an electric vehicle based on a vehicle operator'"'"'s input, the electric vehicle having an electric generator coupled to a first wheel of the electric vehicle, the method comprising:

determining actuation of a first brake lever, the first brake lever being coupled to a brake provided on the first wheel;

determining actuation of a second brake lever, the second brake lever being coupled to a brake provided on a second wheel of the vehicle; and

commanding the generator to generate electricity based on at least one of actuation of the first brake lever and actuation of the second brake lever.

22. The method of claim 21 wherein:

actuation of the first brake lever is determined based on a first switch coupled to the first brake lever and the generator is commanded to operate at a first fraction of maximum regeneration capacity when the first switch is actuated and the second switch is unactuated;

actuation of the second brake lever is determined based on a second switch coupled to the second brake lever and the generator is commanded to operate at a second fraction of maximum regeneration capacity when the second switch is actuated and the first switch is unactuated; and

the generator is commanded to operate at a third fraction of maximum regeneration capacity when the first and second switches are actuated.

23. The method of claim 21 wherein:

actuation of the first brake lever is determined based on a first switch coupled to the first brake lever and the generator is commanded to increase monotonically up to a first fraction of maximum regeneration capacity when the first switch is actuated and the second switch is unactuated; and

actuation of the second brake lever is determined based on a second switch coupled to the second brake lever and the generator is commanded increase monotonically up to a second fraction of maximum regeneration capacity when the second switch is actuated.

24. The method of claim 21 wherein actuation travel of the first brake lever is determined based on a first sensor coupled to the first brake lever and the generator is commanded to apply a regenerative braking force commensurate with the actuation travel of the first brake lever.

25. The method of claim 24 wherein actuation travel of the second brake lever is determined based on a second sensor coupled to the second brake lever and the generator is commanded to apply a regenerative brake force commensurate with the actuation travel of the first and second brake levers.