System and methods for engine-off natural vacuum tests

• US 9,664,126 B2
• Filed: 06/09/2014
• Issued: 05/30/2017
• Est. Priority Date: 06/09/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Dudar, Aed M., Makki, Imad Hassan, Jentz, Robert Roy, Tseng, Fling Finn
• Primary Examiner(s): SMITH, JELANI A
• Application Number:
  US14/300,140
• Publication Number:
  US 20150354480A1
• Time in Patent Office: 1,086 Days
• Field of Search: 701 22
• CPC Class Codes: B60W 20/50 Control strategies for responding to system failures, e.g. for fault diagnosis, failsafe operation or limp mode
• CPC Class Codes: F02D 2041/1412 using a predictive controller
• CPC Class Codes: F02D 2200/701 Information about vehicle position, e.g. from navigation system or GPS signal
• CPC Class Codes: F02D 41/0032 Controlling the purging of the canister as a function of the engine operating conditions
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system
• CPC Class Codes: F02N 11/0814 comprising means for controlling automatic idle-start-stop
• CPC Class Codes: Y10S 903/902 Prime movers comprising electrical and internal combustion motors

Abstract

A method for a vehicle, comprising: during a first condition, closing a canister vent valve responsive to an engine-off event without initiating an engine-off natural vacuum test; during a second condition, following the first condition, closing the canister vent valve responsive to a vehicle-off event; and then initiating an engine-off natural vacuum test. In this way, the completion percentage of the engine-off natural vacuum test will increase.

Claims

1. A method for a vehicle, comprising:

during a first condition;

receiving an indication of a first engine-off event;

receiving an indication that retaining heat during the first engine-off event will increase a likelihood of an engine-off natural vacuum test executing successfully;

following the first engine-off event, closing a canister vent valve based on the heat retention indication without initiating the engine-off natural vacuum test;

receiving an indication of an engine-on event; and

opening the canister vent valve following the engine-on event; and

during a second condition, following the first condition;

receiving an indication of a vehicle-off event, including a second engine-off event;

following the vehicle-off event, closing the canister vent valve based on the vehicle-off event; and

then

initiating the engine-off natural vacuum test.

2. The method of claim 1, where the first condition includes a likelihood of an engine restart during a predetermined window being above a threshold.

3. The method of claim 2, where the second condition includes a likelihood of an engine restart during a predetermined window being below the threshold.

4. The method of claim 2, where the likelihood of an engine restart during the predetermined window is based on a predicted destination determined through machine learning.

5. The method of claim 1, further comprising:

receiving an indication that retaining heat will increase a likelihood of the engine-off natural vacuum test executing successfully; and

closing the canister vent valve prior to the vehicle-off event based on the received indication.

6. The method of claim 5, where the indication that retaining heat will increase the likelihood of the engine-off natural vacuum test executing successfully is based on a total airmass through an engine intake during a current drive cycle being below a threshold.

7. The method of claim 1, where the first condition includes a vehicle-off event, and wherein a vehicle-on event occurs between the first condition and second condition.

8. The method of claim 1, where the indication that retaining heat during the engine-off event will increase the likelihood of the engine-off natural vacuum test executing successfully is based on a predicted route the vehicle will take between the engine-off event and a subsequent vehicle-off event.

9. The method of claim 8, where the predicted route is based on a predicted destination determined through machine learning.

10. A method for a vehicle, comprising:

at a first vehicle-off event, determining a likelihood of a next vehicle-on event during a predetermined window;

closing a canister vent valve at the first vehicle-off event if the determined likelihood is above a threshold; and

maintaining a status of a fuel system at the first vehicle-off event if the determined likelihood is below the threshold.

11. The method of claim 10, where the likelihood of a next vehicle-on event during a predetermined window is based on a predicted destination of the vehicle.

12. The method of claim 11, further comprising:

opening the canister vent valve upon the next vehicle-on event;

receiving an indication of the vehicle reaching the predicted destination;

closing the canister vent valve at a subsequent vehicle-off event; and

executing an engine-off natural vacuum test at the predicted destination.

13. The method of claim 10, further comprising:

receiving an indication that retaining heat during the first vehicle-off event will increase a likelihood of a subsequent engine-off natural vacuum test executing successfully; and

closing the canister vent valve at the first vehicle-off event based on the received indication.

14. The method of claim 13, where the likelihood of a subsequent engine-off natural vacuum test executing successfully is based on a predicted route the vehicle will take between the first vehicle-off event and a subsequent vehicle-off event.

15. A method, comprising:

during vehicle-on, engine-off operation where a hybrid vehicle is en route to a destination and responsive to an indication to perform an engine-off natural vacuum test at a subsequent vehicle-off event, closing a canister vent valve and maintaining a canister purge valve closed;

responsive to vehicle-on, engine-on operation, opening the canister vent valve; and

responsive to the subsequent vehicle-off event, closing the canister vent valve and executing the engine-off natural vacuum test.

16. The method of claim 15, further comprising:

receiving an indication that retaining heat will increase a likelihood of the engine-off natural vacuum test executing successfully; and

then

closing the canister vent valve prior to the vehicle-off event.

17. The method of claim 15, further comprising:

receiving an indication of a fuel tank pressure increasing above a threshold while operating the hybrid vehicle in the vehicle-on, engine-off operation; and

then

opening the canister vent valve.