Regenerative braking method

• US 5,707,115 A
• Filed: 10/07/1996
• Issued: 01/13/1998
• Est. Priority Date: 10/07/1996
• Status: Expired due to Term

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Bodie, Mark Olen, Majeed, Kamal Naif
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US08/723,442
• Time in Patent Office: 463 Days
• Field of Search: 303/3, 303/152, 303/186, 303/112, 303/166, 303/9.62, 303/169, 303/113.5, 303/188, 188/158, 188/156, 188/181 T, 180/165, 180/65.1, 364/426.01, 364/424.026, 364/426.015
• US Class Current: 303/3
• CPC Class Codes: B60L 15/2036 Electric differentials, e.g. for supporting steering vehicles
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/16 longitudinal
• CPC Class Codes: B60L 2240/18 lateral
• CPC Class Codes: B60L 2240/24 Steering angle
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/461 Speed
• CPC Class Codes: B60L 2240/463 Torque
• CPC Class Codes: B60L 2240/465 Slip
• CPC Class Codes: B60L 7/18 Controlling the braking effect B60L7/12, B60L7/14, B60L7/16 take precedence
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B60T 13/586 the retarders being of the electric type
• CPC Class Codes: B60T 13/74 with electrical assistance or drive
• CPC Class Codes: B60T 2270/602 ABS features related thereto
• CPC Class Codes: B60T 8/267 for hybrid systems with different kind of brakes on different axles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

In a vehicle with a first set of first and second wheels coupled to an electric drive system capable of providing regenerative braking and a second set of third and fourth wheels, wherein the vehicle dynamically adjusts a brake proportioning between the first and second sets responsive to a determined wheel speed difference between the first and second sets, the improvement comprising a regenerative braking control method according to the steps of: measuring first, second, third and fourth speeds of the first, second, third and fourth wheels; for each wheel of one of the first and second sets, determining a set-off value inversely relational to a commanded brake torque and a wheel deceleration; determining modified wheel speeds for each wheel of said one of the first and second sets responsive to the wheel speeds and the set-off values; and determining the wheel speed difference between the first and second sets responsive to the modified wheels speeds of said one of the first and second sets and the wheel speeds of the other of the first and second sets, wherein the dynamic adjusting of brake proportioning between the first and second sets increases brake torque load on the first and second wheels, increasing an amount of braking achieved regeneratively.

Claims

1. In a vehicle with a first set of first and second wheels coupled to an electric drive system capable of providing regenerative braking and a second set of third and fourth wheels, wherein the vehicle dynamically adjusts a brake proportioning between the first and second sets responsive to a determined wheel speed difference between the first and second sets, the improvement comprising a regenerative braking control method according to the steps of:

measuring first, second, third and fourth speeds of the first, second, third and fourth wheels;

normalizing the first, second, third and fourth speeds;

for each wheel of one of the first and second sets, determining a wheel speed set-off value inversely relational to a commanded brake torque and a wheel deceleration;

determining modified normalized wheel speeds for each wheel of said one of the first and second sets responsive to the normalized wheel speeds and the wheel-speed set-off values; and

determining the wheel speed difference between the first and second sets responsive to the modified normalized wheels speeds of said one of the first and second sets and the normalized wheel speeds of the other of the first and second sets, wherein

the dynamic adjusting of brake proportioning between the first and second sets responsive to the determined wheel speed difference is responsive to the speed set-off values to increase brake torque load on the first and second wheels, increasing an amount of braking achieved regeneratively.

2. In a vehicle with a first set of first and second wheels coupled to an electric drive system capable of providing regenerative braking and a second set of third and fourth wheels, wherein the vehicle dynamically adjusts a brake proportioning between the first and second sets responsive to a determined wheel speed difference between the first and second sets, the improvement comprising a regenerative braking control method according to the steps of:

measuring first, second, third and fourth speeds of the first, second, third and fourth wheels;

for each wheel of one of the first and second sets, determining a wheel speed set-off value inversely relational to a commanded brake torque and a wheel deceleration;

determining modified wheel speeds for each wheel of said one of the first and second sets responsive to the wheel speeds and the wheel speed set-off values; and

determining the wheel speed difference between the first and second sets responsive to the modified wheels speeds of said one of the first and second sets and the wheel speeds of the other of the first and second sets, wherein

the dynamic adjusting of brake proportioning between the first and second sets responsive to the determined wheel speed difference is responsive to the wheel speed set-off values to increase brake torque load on the first and second wheels, increasing an amount of braking achieved regeneratively.

3. A regenerative braking control method according to claim 2 wherein the first, second, third and fourth wheel speeds are normalized.