ELECTRIC CURRENT BASED ENGINE AUTO STOP INHIBIT ALGORITHM AND SYSTEM IMPLEMENTING SAME

• US 20130018569A1
• Filed: 07/11/2011
• Published: 01/17/2013
• Est. Priority Date: 07/11/2011
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Sangameswaran, Sangeetha, Harpenau, Kevin Roy, Pebley, Kirk, Celinske, David, Rademacher, Eric Michael
• Granted Patent: US 10,480,477 B2
• Time in Patent Office: Days
• US Class Current: 701/112
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F02N 11/0825 related to prevention of engine restart failure, e.g. disabling automatic stop at low battery state
• CPC Class Codes: F02N 2200/062 Battery current
• CPC Class Codes: F02N 2200/0809 Electrical loads
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A vehicle includes an engine and at least one controller. The at least one controller periodically determines an estimated current to be demanded by vehicle electrical loads during an auto stop of the engine, compares the estimated current with a threshold current, and inhibits an auto stop of the engine if the estimated current is greater than the threshold current for a predetermined period of time.

Claims

1. A vehicle comprising:

an engine; and

at least one controller configured to periodically determine an estimated current to be demanded by vehicle electrical loads during an auto stop of the engine, to compare the estimated current with a threshold current, and to inhibit an auto stop of the engine if the estimated current is greater than the threshold current for a predetermined period of time.

2. The vehicle of claim 1 further comprising (i) a battery and (ii) an alternator or integrated starter generator, wherein the at least one controller is further configured to determine a net current provided by the (i) battery and (ii) alternator or integrated starter generator, and wherein determining an estimated current to be demanded by vehicle electrical loads during an auto stop of the engine includes determining a difference between the net current and an expected change in current demanded by vehicle electrical loads during an auto stop of the engine.

3. The vehicle of claim 1 wherein inhibiting an auto stop of the engine includes preventing the engine from stopping.

4. The vehicle of claim 1 wherein the at least one controller is further configured to allow an auto stop of the engine if the estimated current is less than the threshold current.

5. The vehicle of claim 4 wherein the at least one controller is further configured to, while a speed of the engine is approximately zero, periodically determine a battery current, compare the battery current with the threshold current, and initiate an auto start of the engine if the battery current is greater than the threshold current for another predetermined period of time.

6. A vehicle comprising:

an engine; and

at least one controller configured to detect an engine auto stop inhibit condition when an estimate of current to be demanded by vehicle electrical loads during an auto stop of the engine is greater than a threshold current and, in response to detecting the engine auto stop inhibit condition, prevent the engine from auto stopping.

7. The vehicle of claim 6 further comprising (i) a battery and (ii) an alternator or integrated starter generator, wherein the at least one controller is further configured to determine a net current provided by the (i) battery and (ii) alternator or integrated starter generator, and wherein the at least one controller is further configured to determine the estimate of current to be demanded by vehicle electrical loads during an auto stop of the engine based on a difference between the net current and an expected change in current demanded by vehicle electrical loads during an auto stop of the engine.

8. The vehicle of claim 7 wherein the at least one controller is further configured to determine the estimate of current prior to initiating an auto stop of the engine.

9. The vehicle of claim 6 wherein the at least one controller is further configured to detect an engine auto stop permit condition when the estimate of current to be demanded by vehicle electrical loads during an auto stop of the engine is less than the threshold current and, in response to detecting the engine auto stop permit condition, allow the engine to auto stop.

10. The vehicle of claim 9 wherein the at least one controller is further configured to, while a speed of the engine is approximately zero, determine a battery current, compare the battery current with the threshold current, and initiate an auto start of the engine if the battery current is greater than the threshold current.

11. A method for controlling an engine of a vehicle comprising:

determining an estimated current to be demanded by vehicle electrical loads during an auto stop of the engine;

comparing the estimated current with a threshold current;

inhibiting an auto stop of the engine if the estimated current is greater than the threshold current; and

allowing an auto stop of the engine if the estimated current is less than the threshold current.

12. The method of claim 11 further comprising determining a net current provided by (i) a battery and (ii) an alternator or integrated starter generator, wherein determining an estimated current to be demanded by vehicle electrical loads during an auto stop of the engine includes determining a difference between the net current and an expected change in current demanded by vehicle electrical loads during an auto stop of the engine.

13. The method of claim 12 wherein, during an auto stop of the engine, the vehicle electrical loads are controlled such that they consume an amount of current approximately equal to the estimated current.

14. The method of claim 11 wherein the estimated current is determined prior to initiating an auto stop of the engine.

15. The method of claim 11 wherein inhibiting an auto stop of the engine includes preventing the engine from stopping.

16. The method of claim 11 wherein an auto stop of the engine is inhibited if the estimated current is greater than the threshold current for a predetermined period of time.

17. The method of claim 11 wherein an auto stop of the engine is allowed if the estimated current is less than the threshold current for a predetermined period of time.

18. The method of claim 11 further comprising, while a speed of the engine is approximately zero, determining a battery current, comparing the battery current with the threshold current, and initiating an auto start of the engine if the battery current is greater than the threshold current.

19. The method of claim 18 wherein the step of determining an estimated current to be demanded by vehicle electrical loads during an auto stop of the engine is suspended while speed of the engine decreases to approximately zero after initiation of an auto stop of the engine.