Method for controlling a stop/start vehicle

• US 10,012,201 B1
• Filed: 04/19/2017
• Issued: 07/03/2018
• Est. Priority Date: 04/19/2017
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Chen, Hanyang B.
• Primary Examiner(s): Low, Lindsay
• Assistant Examiner(s): Jin, George
• Application Number:
  US15/491,275
• Time in Patent Office: 440 Days
• Field of Search: 324430
• CPC Class Codes: F02N 11/0818 Conditions for starting or stopping the engine or for deactivating the idle-start-stop mode
• 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 11/0848 with means for detecting successful engine start, e.g. to stop starter actuation
• CPC Class Codes: F02N 2300/2011 Control involving a delay; Control involving a waiting period before engine stop or engine start
• CPC Class Codes: G01R 31/3647 for determining the ability of a battery to perform a critical function, e.g. cranking
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method for allowing or prohibiting automatic engine stopping and starting is presented. In one example, an engine cranking time is predicted and compared to a threshold value to determine whether or not automatic engine stopping and starting is to be allowed or prohibited. The predicted engine cranking time is a metric for judging whether or not vehicle occupants might find a possible subsequent vehicle operation delay objectionable due to an engine starting event.

Claims

1. A vehicle operating method, comprising:

automatically stopping and starting an engine; and

prohibiting automatic stopping of the engine in response to an estimated engine cranking time exceeding a threshold.

2. The method of claim 1, where the estimate of engine cranking time is based on an amount of electrical energy consumed to crank the engine from a most recent engine stop to a first combustion event since the most recent engine stop.

3. The method of claim 1, where automatically stopping the engine includes ceasing fuel flow to the engine and ceasing engine rotation, and further comprising:

automatically starting the engine in response to the estimated engine cranking time exceeding the threshold after the engine has been automatically stopped.

4. The method of claim 1, where the estimate of engine cranking time is based on an maximum magnitude of engine cranking current.

5. The method as claimed in claim 4, where the estimate of engine cranking time is performed while the engine is operating.

6. The method of claim 1, further comprising prohibiting automatic engine stopping in further response to a battery state of charge.

7. The method of claim 1, where the estimated engine cranking time is based on internal resistance of a battery.

8. The method of claim 7, where the estimated engine cranking time is further based on resistance of a starter motor.

9. A vehicle operating method, comprising:

automatically stopping and starting an engine;

predicting an engine cranking time; and

prohibiting automatic stopping of the engine in response to the predicted engine cranking time exceeding a threshold.

10. The method of claim 9, further comprising predicting a maximum magnitude of battery current during engine cranking.

11. The method of claim 10, further comprising correlating the predicted maximum magnitude of battery current during engine cranking to the predicted engine cranking time.

12. The method of claim 9, where the predicted engine cranking time is responsive to resistance of starter motor windings and further comprising:

automatically starting the engine in response to the predicted engine cranking time exceeding the threshold after the engine has been automatically stopped.

13. The method of claim 9, where the predicted engine cranking time is responsive to internal resistance of a battery.

14. The method of claim 9, where the predicted engine cranking time is responsive to voltage of a battery before engine cranking.

15. The method of claim 9, where the predicted engine cranking time is responsive to heat generated in a starter motor.

16. A vehicle system, comprising:

an engine including a starter motor;

a battery selectively supplying charge to the starter motor; and

a controller including executable instructions stored in non-transitory memory to predict an engine cranking time while the engine is rotating and prohibit automatic stopping of the engine in response to the predicted engine cranking time exceeding a threshold, and instructions to automatically start the engine in response to the predicted engine cranking time exceeding the threshold while the engine is stopped due to an automatic engine stop.

17. The vehicle system of claim 16, further comprising instructions to predict the engine cranking time based on a maximum engine cranking current.

18. The vehicle system of claim 16, further comprising instructions to predict the engine cranking time based on energy to crank the engine.

19. The vehicle system of claim 16, where the engine cranking time is a time from rotating the engine from zero speed to a first combustion event since a most recent engine stop.

20. The vehicle system of claim 16, where the engine cranking time is based on resistance of starter motor windings.