Vehicle regenerative braking control apparatus and method

• US 20060196712A1
• Filed: 03/03/2006
• Published: 09/07/2006
• Est. Priority Date: 03/04/2005
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Sugimoto, Tomonaga, Isono, Youichi, Izu, Yoshiyuki, Toyota, Hiromitsu
• Granted Patent: US 7,426,975 B2
• Time in Patent Office: Days
• US Class Current: 180/165
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/461 Speed
• CPC Class Codes: B60L 2240/465 Slip
• CPC Class Codes: B60L 3/108 whilst braking, i.e. ABS
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B60T 2270/602 ABS features related thereto
• CPC Class Codes: B60T 2270/608 Electronic brake distribution (EBV/EBD) features related thereto
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/18 : including control of braking systems
• CPC Class Codes: B60W 20/00 : Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/13 : in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2520/28 : Wheel speed
• CPC Class Codes: B60W 30/18145 : Cornering
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles

Abstract

A regenerative braking control apparatus for a wheeled vehicle, includes: a regenerative braking unit arranged to produce a regenerative braking effort for the vehicle; and a control unit connected for signal communication to the regenerative braking unit, and configured to perform the following: measuring a wheel speed deviation defined as a difference between a speed of a front wheel set of the vehicle and a speed of a rear wheel set of the vehicle; and controlling the regenerative braking effort in accordance with the wheel speed deviation during cornering. The control unit is configured to control the regenerative braking effort to decrease with an increase in the wheel speed deviation during cornering braking, and configured to perform braking for the vehicle in accordance with an operation of slowdown request, prioritizing a regenerative braking effort for one of the front wheel set and the rear wheel set of the vehicle.

Claims

1. A regenerative braking control apparatus for a wheeled vehicle, comprising:

a regenerative braking unit arranged to produce a regenerative braking effort for the vehicle; and

a control unit connected for signal communication to the regenerative braking unit, and configured to perform the following;

measuring a wheel speed deviation defined as a difference between a speed of a front wheel set of the vehicle and a speed of a rear wheel set of the vehicle; and

controlling the regenerative braking effort in accordance with the wheel speed deviation during cornering.

2. The regenerative braking control apparatus as claimed in claim 1, wherein the control unit is configured to control the regenerative braking effort to decrease with an increase in the wheel speed deviation during cornering braking.

3. The regenerative braking control apparatus as claimed in claim 2, wherein the control unit is configured to perform braking for the vehicle in accordance with an operation of slowdown request, prioritizing a regenerative braking effort for one of the front wheel set and the rear wheel set of the vehicle.

4. The regenerative braking control apparatus as claimed in claim 1, wherein the control unit is configured to determine the wheel speed deviation as a difference between an average speed of a non-regenerative-braking-applied wheel set of the vehicle and a speed of a regenerative-braking-applied outside wheel of the vehicle during cornering.

5. The regenerative braking control apparatus as claimed in claim 1, wherein the control unit is configured to perform the following:

adjusting an upper limit to decrease with an increase in the wheel speed deviation; and

limiting the regenerative braking effort with the upper limit during cornering.

6. The regenerative braking control apparatus as claimed in claim 5, wherein the control unit is configured to hold the upper limit for the regenerative braking effort constant in a region where the wheel speed deviation is larger than or equal to a predetermined threshold.

7. The regenerative braking control apparatus as claimed in claim 1, wherein the control unit is configured to perform the following:

determining whether or not the vehicle is traveling straight; and

inhibiting the controlling the regenerative braking effort, when it is determined that the vehicle is traveling straight.

8. The regenerative braking control apparatus as claimed in claim 1, wherein the control unit is configured to inhibit the controlling the regenerative braking effort, when an intervention of a control for dynamic behavior of the vehicle is present.

9. The regenerative braking control apparatus as claimed in claim 1, wherein the regenerative braking unit is arranged to produce the regenerative braking effort for the front wheel set, and wherein the control unit comprises:

a desired regenerative braking torque processing module configured to determine a desired regenerative braking torque in accordance with an operation of slowdown request;

a regenerative braking torque limit computing section configured to determine the wheel speed deviation, and to determine an upper limit to decrease with an increase in the wheel speed deviation; and

a final output regenerative braking torque processing module configured to select a lower one of the desired regenerative braking torque and the upper limit as a setpoint of the regenerative braking effort.

10. The regenerative braking control apparatus as claimed in claim 1, wherein the regenerative braking unit is arranged to produce the regenerative braking effort for the front wheel set and the rear wheel set, and wherein the control unit is configured to control the regenerative braking effort to decrease with an increase in the wheel speed deviation during cornering braking in a first mode where the regenerative braking effort for one of the front wheel set and the rear wheel set is inhibited.

11. The regenerative braking control apparatus as claimed in claim 10, wherein the control unit is configured to perform the following:

adjusting an upper limit to decrease with an increase in the wheel speed deviation;

dividing the upper limit between a front upper limit and a rear upper limit in proportions of the regenerative braking effort for the front wheel set and the regenerative braking effort for the rear wheel set; and

limiting the regenerative braking effort for the front wheel set and the regenerative braking effort for the rear wheel set with the front upper limit and the rear upper limit, respectively, during cornering braking in a second mode where the regenerative braking effort for the front wheel set and the regenerative braking effort for the rear wheel set are allowed.

12. A braking control apparatus for a vehicle, comprising:

a non-regenerative braking unit arranged to produce a non-regenerative braking effort for the vehicle;

a regenerative braking unit arranged to produce a regenerative braking effort for the vehicle; and

a control unit connected for signal communication to the non-regenerative braking unit and the regenerative braking unit, and configured to perform the following;

determining a desired regenerative braking effort in accordance with an operation of slowdown request;

determining an undesirability indicator indicative of a degree of undesirability of cornering behavior of the vehicle under influence of the regenerative braking effort;

controlling the regenerative braking effort in accordance with the desired regenerative braking effort and the undesirability indicator during cornering; and

controlling the non-regenerative braking effort in accordance with the desired regenerative braking effort and the controlled regenerative braking effort.

13. The braking control apparatus as claimed in claim 12, wherein the control unit is configured to perform the following:

defining the undesirability indicator to tend to increase with increase in the regenerative braking effort; and

controlling the regenerative braking effort to decrease with an increase in the undesirability indicator during cornering braking.

14. The braking control apparatus as claimed in claim 13, wherein the control unit is configured to perform the following:

adjusting an upper limit to decrease with an increase in the undesirability indicator; and

limiting the regenerative braking effort with the upper limit during cornering.

15. The braking control apparatus as claimed in claim 12, wherein the control unit is configured to define the undesirability indicator as a deviation from a desired steer characteristic of the vehicle.

16. A regenerative braking control apparatus for a wheeled vehicle, comprising:

regenerative braking means for producing a regenerative braking effort for the vehicle; and

control means for performing the following;

measuring a wheel speed deviation defined as a difference between a speed of a front wheel set of the vehicle and a speed of a rear wheel set of the vehicle; and

controlling the regenerative braking effort in accordance with the wheel speed deviation during cornering.

17. A regenerative braking control method for a wheeled vehicle comprising a regenerative braking unit arranged to produce a regenerative braking effort for the vehicle, the regenerative braking control method comprising:

measuring a wheel speed deviation defined as a difference between a speed of a front wheel set of the vehicle and a speed of a rear wheel set of the vehicle; and

controlling the regenerative braking effort in accordance with the wheel speed deviation during cornering.