Apparatus and method to maximize vehicle functionality and fuel economy with improved drivability during engine auto stop-start operations

• US 9,776,635 B2
• Filed: 02/09/2015
• Issued: 10/03/2017
• Est. Priority Date: 02/09/2015
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Khafagy, Hafiz S., Pebley, Kirk, Bouse, William J., Deljevic, Zeljko
• Primary Examiner(s): Moulis, Thomas
• Assistant Examiner(s): BAILEY, JOHN D
• Application Number:
  US14/616,953
• Publication Number:
  US 20160229403A1
• Time in Patent Office: 967 Days
• Field of Search: 701112, 701113, 1231794, 12333922, 477111
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 2510/18 Braking system
• CPC Class Codes: B60W 2510/202 Steering torque
• CPC Class Codes: B60W 2510/205 Steering speed
• CPC Class Codes: B60W 2510/305 Power absorbed by auxiliaries
• CPC Class Codes: B60W 2520/04 Vehicle stop
• CPC Class Codes: B60W 2710/06 Combustion engines, Gas turbines
• CPC Class Codes: B60W 2710/248 Current for loading or unloading
• CPC Class Codes: B60W 30/00 Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: B60W 30/18054 at stand still, e.g. engine in idling state hill holding B60W30/18118
• CPC Class Codes: F02N 11/08 Circuits or control means specially adapted for starting of engines
• CPC Class Codes: F02N 11/0814 comprising means for controlling automatic idle-start-stop
• CPC Class Codes: F02N 11/0866 comprising several power sources, e.g. battery and capacitor or two batteries
• CPC Class Codes: F02N 2200/0808 Steering state, e.g. state of power assisted steering
• CPC Class Codes: F02N 2250/02 Battery voltage drop at start, e.g. drops causing ECU reset
• CPC Class Codes: F02N 2300/2011 Control involving a delay; Control involving a waiting period before engine stop or engine start
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An auto stop-start equipped vehicle power management system includes a primary power source supplying energy to an electrical starter to crank a vehicle engine and a secondary power source coupled in parallel to the primary power source. The secondary power source supplies energy to electric loads during an engine auto stop-start operation. The electrical loads maintain vehicle subsystem functionality during the engine auto stop-start operation. The energy supplied to the electrical loads is current limited during the engine auto stop-start operation. A controllable switch decouples the secondary power source from the primary power source and starter motor during the engine auto stop-start operation. Operating parameters of the electrical loads are monitored during the engine auto stop-start operation. If a respective operating parameter threshold associated with the electrical loads is exceeded during the engine auto stop-start operation, then the vehicle engine is automatically restarted and the controllable switch is subsequently closed.

Claims

1. An auto stop-start equipped vehicle power management system comprising:

a primary power source supplying energy to an electrical starter to crank a vehicle engine;

a secondary power source coupled in parallel to the primary power source, the secondary power source supplying energy to electric loads during an engine auto stop-start operation, the electrical loads maintaining vehicle subsystem functionality during the engine auto stop-start operation;

a controllable switch decoupling the secondary power source from the primary power source and starter motor during the engine auto stop-start operation;

wherein operating parameters of the electrical loads are monitored during the engine auto stop-start operation, wherein if a respective operating parameter threshold associated with the electrical loads is exceeded during the engine auto stop-start operation, the vehicle engine is automatically restarted and the controllable switch is subsequently closed.

2. The system of claim 1 wherein the energy supplied to the electrical loads is current limited during the engine auto stop-start operation.

3. The system of claim 1 wherein the respective operating parameter threshold is calibratable.

4. The system of claim 3 wherein the electrical loads include an EPAS system.

5. The system of claim 4 wherein the operating parameters include a steering rate applied to a steering system, wherein the operating parameter threshold includes a value in a range of 80-270 deg/sec.

6. The system of claim 4 wherein the operating parameters include a steering wheel angle applied to a steering system, wherein the operating parameter threshold includes a value in a range of +/−

300 degrees.

7. The system of claim 4 wherein the operating parameters include a steering torque applied to a steering system, wherein the operating parameter threshold includes 5 Nm for at least 0.5-2.5 seconds.

8. The system of claim 4 wherein a body control module sets a maximum current limit, wherein the maximum current limit includes value in a range of 30-100 Amps.

9. The system of claim 4 wherein the engine auto stop-start operation is performed when the vehicle is stationary.

10. The system of claim 4 wherein the engine auto stop-start operation is performed when the vehicle executes a rolling stop operation.

11. The system of claim 3 wherein the electrical loads include a heating ventilation and air conditioning system.

12. The system of claim 3 wherein the electrical loads include an electrical braking system.

13. A method of managing power in an auto stop-start equipped vehicle comprising the steps of:

supplying energy, by a primary power source, to a starter motor to crank a vehicle engine;

supplying energy, by a secondary power source, to electric loads during an engine auto stop-start operation, the secondary power source coupled in parallel to the primary power source, the electrical loads maintaining vehicle subsystem functionality during the engine auto stop-start operation;

decoupling the secondary power source from the primary power source and an electrical starter by a controllable switch during the engine auto stop-start operation;

monitoring operating parameters of the electrical loads during the engine auto stop-start operation;

determining whether a respective operating parameter threshold associated with the electrical loads is exceeded during the auto stop-start operation;

automatically restarting the vehicle engine in response to exceeding the respective operating parameter during the engine auto stop-start operation; and

subsequently closing the controllable switch for electrically coupling a primary power source to the secondary power source.

14. The method of claim 13 further comprising the step of current limiting the energy supplied to the electrical loads during the engine auto stop-start operation.

15. The method of claim 14 wherein the electrical loads include an EPAS system.

16. The method of claim 15 wherein a maximum current limit is selected from a range of 30-100 Amps.

17. The method of claim 16 wherein the operating parameters include a steering rate applied to a steering system, wherein the operating parameter threshold is selected from a range of 80-270 deg/sec.

18. The method of claim 15 wherein the operating parameters include a steering wheel angle applied to a steering system, wherein the operating parameter threshold is selected from a range of +/−

300 degrees.

19. The method of claim 15 wherein the operating parameters include a steering torque applied to a steering system, wherein the operating parameter threshold includes 5 Nm for at least 0.5-2.5 seconds.

20. A system comprising:

a primary power source energizing a starter motor;

a secondary power source energizing electrical loads for maintaining subsystem functionality during an engine auto stop-start operation;

a switch decoupling the primary and secondary power source during the engine auto stop-start operation;

wherein operating parameters associated with electrical loads are monitored, wherein the engine is restarted and the switch is subsequently closed in response to exceeding an operating parameter threshold during the engine auto stop-start operation.