Method and apparatus for control of a hybrid electric vehicle to achieve a target life objective for an energy storage device

• US 7,730,984 B2
• Filed: 06/07/2006
• Issued: 06/08/2010
• Est. Priority Date: 06/07/2006
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Zettel, Andrew M., Heap, Anthony H., Cawthorne, William R.
• Primary Examiner(s): Restifo; Jeffrey J
• Application Number:
  US11/422,709
• Publication Number:
  US 20070284163A1
• Time in Patent Office: 1,462 Days
• Field of Search: 180/65.29, 180/65.285, 180/65.265, 702/63
• US Class Current: 180/65.29
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2260/56 Temperature prediction, e.g. for pre-cooling
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method for determining a preferred operating gradient for use in attaining a life objective for an electrical energy storage device in a hybrid vehicle is disclosed. A present state-of-life of the electrical energy storage device is provided and a life target for the electrical energy storage device is established as a predetermined limit in a predetermined metric at a predetermined state-of-life of the electrical energy storage device. A state-of-life gradient is then determined with respect to the predetermined metric which converges the state-of-life of the electrical energy storage device to the life target.

Claims

1. Method for operating a hybrid electric powertrain including an electrical energy storage device configured to exchange electrical energy with a hybrid vehicular powertrain including first and second electric machines, each machine operable to impart torque to a two-mode, compound-split electro-mechanical transmission having four fixed gear ratios and two continuously variable operating modes, comprising:

establishing a state-of-life parameter associated with the electrical energy storage device;

providing a present state-of-life of the electrical energy storage device;

establishing a life target for the electrical energy storage device as a predetermined limit in a predetermined metric at a predetermined state-of-life of the electrical energy storage device;

determining a state-of-life gradient with respect to the predetermined metric which converges the state-of-life of the electrical energy storage device to the life target; and

operating the electric machines such that the electrical energy storage device state-of-life substantially tracks the state-of-life gradient.

2. The method of claim 1 wherein the predetermined limit in the predetermined metric at the predetermined state-of-life of the electrical energy storage device is associated with an end of service life of the electrical energy storage device.

3. The method as in claim 2 wherein the predetermined metric comprises elapsed service time of the electrical energy storage device.

4. The method of claim 2 wherein the predetermined metric comprises an accumulated vehicle distance traveled.

5. The method of claim 1 wherein the life target for the electrical energy storage device is associated with one of elapsed service time of the electrical energy storage device and an accumulated vehicle distance traveled.

6. The method of claim 5 wherein the life target is normalized with respect to the one of elapsed service time of the electrical energy storage device and the accumulated vehicle distance traveled upon which the life target is based.

7. Method for operating a hybrid electric powertrain including an electrical energy storage device adapted for exchanging electrical energy with a hybrid vehicular powertrain including first and second electric machines, each machine operable to impart torque to a two-mode, compound-split electro-mechanical transmission having four fixed gear ratios and two continuously variable operating modes, comprising:

establishing a state-of-life parameter associated with the electrical energy storage device;

providing a state-of-life gradient based on a present state-of-life of the electrical energy storage device and at least one predetermined limit of a predetermined metric associated with the state-of-life; and

controlling electrical energy storage device current during periods of vehicle activity such that the electrical energy storage device state-of-life substantially tracks the state-of-life gradient.

8. The method of claim 7 wherein controlling the electrical energy storage device current such that electrical energy storage device state-of-life substantially tracks the state-of-life gradient comprises:

providing a plurality of predicted effects upon the electrical energy storage device state-of-life based on a plurality of potential electrical energy storage device currents during periods of vehicle activity; and

controlling the electrical energy storage device current during periods of vehicle activity based on the predicted effects and the state-of-life gradient.

9. The method of claim 8 wherein controlling electrical energy storage device current during periods of vehicle activity comprises:

operating the electric machines based on the predicted effects and the state-of-life gradient.

10. Method for operating a hybrid electric powertrain including an electrical energy storage device configured to exchange electrical energy with a hybrid vehicular powertrain including first and second electric machines, each machine configured to impart torque to a two-mode, compound-split electro-mechanical transmission having four fixed gear ratios and two continuously variable operating modes, comprising:

establishing an operating parameter comprising a state-of-life associated with the electrical energy storage device; and

controlling power transmitted between the electrical energy storage device and the first and second electric machines during periods of vehicle activity such that the state-of-life associated with the electrical energy storage device is less than a predetermined value when a target life objective is attained.

11. The method of claim 10, wherein controlling power transmitted between the electrical energy storage device and the first and second electric machines during periods of vehicle activity such that the state-of-life associated with the electrical energy storage device is less than a predetermined value when the target life objective is attained further comprises:

calculating a life factor associated with an accumulated time and an accumulated distance of operation of the powertrain;

determining a target state-of-life gradient associated the life factor, the state-of-life, and the target life objective; and

,

controlling electrical power transmitted between the electrical energy storage device and the powertrain to track the target state-of-life gradient.

12. The method of claim 11, wherein controlling electrical power transmitted between the electrical energy storage device and the powertrain to track the target state-of-life gradient further comprises:

determining potential changes in the state-of-life for the electrical energy storage device associated with each of an array of potential electrical currents through the electrical energy storage device during periods of vehicle activity; and

,

selecting one of the array of potential electrical currents having a potential change in the state-of-life of the electrical energy storage device that tracks the target state-of-life gradient.

13. The method of claim 12, wherein determining the potential changes in the state-of-life for the electrical energy storage device associated with each of an array of potential electrical currents through the electrical energy storage device during periods of vehicle activity further comprises:

selecting the array of potential electrical currents through the electrical energy storage device; and

,

determining a corresponding array of changes in the state-of-life for the electrical energy storage device associated with the array of potential electrical currents through the electrical energy storage device;

wherein changes in the state-of-life for the electrical energy storage device are associated with a time-based integration of the electrical currents through the electrical energy storage device, depth of discharge of the energy storage device, and, operating temperature of the electrical energy storage device.

14. The method of claim 10, wherein controlling power transmitted between the electrical energy storage device and the electric machines during periods of vehicle activity such that the operating state of the electrical energy storage device is less than a predetermined value further comprises:

determining the operating state of the electrical energy storage device, comprising;

monitoring electrical current through the electrical energy storage device;

monitoring a state-of-charge of the electrical energy storage device;

monitoring a temperature of the electrical energy storage device during periods of vehicle activity and inactivity; and

,

determining a state-of-life of the electrical energy storage device associated with the electrical energy storage device current, the state-of-charge of the electrical energy storage device, and, the temperature of the electrical energy storage device during periods of vehicle activity and inactivity.