Control algorithm for low-voltage circuit in hybrid and conventional vehicles

• US 8,364,332 B2
• Filed: 01/15/2010
• Issued: 01/29/2013
• Est. Priority Date: 01/15/2010
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Bergkoetter, Brenton J., Aldrich, William L. III, Tamai, Goro
• Primary Examiner(s): Camby, Richard M.
• Application Number:
  US12/687,918
• Publication Number:
  US 20110178661A1
• Time in Patent Office: 1,110 Days
• Field of Search: 701/22, 701/36, 701/70, 477/2, 477/3, 477/4, 180/65.1, 180/65.21, 180/65.31, 180/65.265, 180/65.285, 180/65.29
• US Class Current: 701/22
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method for controlling a low-voltage circuit of a vehicle having a generator includes monitoring operating conditions of the vehicle and determining whether surplus generator load is available. Available surplus generator load is captured and used to power the low-voltage circuit. The low-voltage circuit may include a low-voltage battery, which may be charged with the surplus generator load. The surplus generator load may be utilized for anti-sulfation of the low-voltage battery. The method is usable with both a hybrid vehicle and a conventional vehicle. The method may further include powering the low-voltage circuit with energy stored in the low-voltage battery as a result of charging the low-voltage battery with the surplus generator load.

Claims

1. A method for controlling a low-voltage circuit of a hybrid vehicle having a generator and a hybrid circuit in communication with the low-voltage circuit, wherein the hybrid circuit includes a hybrid battery and the low-voltage circuit includes a low-voltage battery, the method comprising:

monitoring operating conditions of the vehicle;

determining whether surplus generator load is available, wherein determining whether surplus generator load is available includes;

determining whether the hybrid battery is capable of accepting power generated through regenerative braking, and

determining whether the low-voltage battery is capable of accepting power generated through regenerative braking;

capturing the available surplus generator load;

charging the low-voltage battery with the surplus generator load;

utilizing the surplus generator load for anti-sulfation of the low-voltage battery; and

powering the low-voltage circuit with the surplus generator load.

2. The method of claim 1, wherein determining whether the hybrid battery is capable of accepting power generated through regenerative braking includes determining one of the temperature of the hybrid battery and the state of charge of the hybrid battery.

3. The method of claim 2, wherein determining whether the hybrid battery is capable of accepting power generated through regenerative braking includes determining whether the temperature of the hybrid battery is above a minimum temperature and below a maximum temperature.

4. The method of claim 3, further comprising powering the low-voltage circuit with energy stored in the low-voltage battery as a result of charging the low-voltage battery with the surplus generator load.

5. The method of claim 4, wherein monitoring operating conditions of the vehicle includes monitoring for one of a negative torque request and a braking event.

6. The method of claim 1, further comprising powering the low-voltage circuit with energy stored in the low-voltage battery as a result of charging the low-voltage battery with the surplus generator load.

7. A method for controlling a low-voltage circuit of a vehicle having a generator, wherein the vehicle is a hybrid vehicle and further includes a hybrid circuit in communication with the low-voltage circuit and having a hybrid battery, and wherein the low-voltage circuit includes a low-voltage battery, the method comprising:

monitoring operating conditions of the vehicle for one of a negative torque request and a braking event;

determining whether surplus generator load is available, wherein determining whether surplus generator load is available includes determining whether the hybrid battery is capable of accepting power generated through regenerative braking, and determining whether the low-voltage battery is capable of accepting power generated through regenerative braking;

capturing the available surplus generator load;

powering the low-voltage circuit with the surplus generator load;

charging the low-voltage battery with the surplus generator load; and

powering the low-voltage circuit with energy stored in the low-voltage battery as a result of charging the low-voltage battery with the surplus generator load.

8. The method of claim 7, wherein determining whether the hybrid battery is capable of accepting power generated through regenerative braking includes determining one of the temperature of the hybrid battery and the state of charge of the hybrid battery.

9. The method of claim 8, wherein determining whether the hybrid battery is capable of accepting power generated through regenerative braking includes determining whether the temperature of the hybrid battery is above a minimum temperature and below a maximum temperature.

10. The method of claim 9, further comprising utilizing the surplus generator load for anti-sulfation of the low-voltage battery.

11. The method of claim 10,

wherein the low-voltage battery has a first voltage set point prior to charging the low-voltage battery with the surplus generator load;

and

wherein charging the low-voltage battery with the surplus generator load includes increasing the low-voltage battery to a second voltage set point.

12. The method of claim 11, further including:

ending charging of the low-voltage battery with the surplus generator load; and

decreasing the low-voltage battery from the second voltage set point to the first voltage set point.

13. The method of claim 12, wherein decreasing the low-voltage battery from the second voltage set point to the first voltage set point further includes a gradual transition from the second voltage set point to the first voltage set point.