Evaporative emissions testing based on historical and forecast weather data

• US 9,696,234 B2
• Filed: 07/25/2014
• Issued: 07/04/2017
• Est. Priority Date: 07/25/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Tseng, Fling Finn, Yang, Hsin-hsiang, Makki, Imad Hassan, Dudar, Aed M., Jentz, Robert Roy
• Primary Examiner(s): West, Paul
• Application Number:
  US14/341,571
• Publication Number:
  US 20160025589A1
• Time in Patent Office: 1,075 Days
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system
• CPC Class Codes: G01M 3/025 Details with respect to the testing of engines or engine parts

Abstract

A method for a vehicle, comprising: initiating an engine-off natural vacuum test based on an ambient temperature change potential over a testing duration. The ambient temperature change potential may be based on historic weather data and further based on forecast weather data. In this way, the engine-off natural vacuum test may be executed only when conditions favor an in-tank temperature change significant enough to cause a threshold change in fuel tank pressure, thus reducing the number of aborted tests and increasing the test'"'"'s overall performance metrics.

Claims

1. A method for a vehicle, comprising:

initiating an engine-off natural vacuum test based on an ambient temperature change potential over a testing duration, the ambient temperature change potential based on historic weather data and forecast weather data retrieved from an off-board computing system;

re-sampling the historic weather data and forecast weather data;

distributing the re-sampled data into an aggregated data set; and

applying a low-pass filter to the aggregated data set, the low-pass filter configured such that more recent data is given more weight than less recent data.

2. The method of claim 1, where the ambient temperature change potential over the testing duration is based on an integration of the filtered aggregated data set.

3. The method of claim 2, further comprising:

determining a temperature gradient over the testing duration based on a comparison of the ambient temperature change potential and a fuel system temperature.

4. The method of claim 3, further comprising:

initiating an engine-off natural vacuum test responsive to the determined temperature gradient being greater than a threshold.

5. The method of claim 1, further comprising:

adjusting a property of the low-pass filter based on a recorded ambient temperature change during the testing duration.

6. The method of claim 1, further comprising:

validating a result of an engine-off natural vacuum test based on weather data recorded during the testing duration.

7. A system for a vehicle, comprising:

a fuel system coupled to an evaporative emissions system; and

a controller configured with instructions in non-transitory memory, that when executed cause the controller to;

responsive to an indication to perform an engine-off natural vacuum test, and further responsive to a vehicle-off event, retrieving historic weather data and forecast weather data from an off-board computing system;

re-sampling the historic weather data and the forecast weather data;

distributing the re-sampled data into an aggregated data set;

applying a low-pass filter to the aggregated data set, the low-pass filter configured such that more recent data is given more weight than less recent data;

determining an ambient temperature change potential over a testing duration; and

initiating the engine-off natural vacuum test based on the ambient temperature change potential.

8. The system of claim 7, further comprising:

an on-board global positioning system; and

wherein the controller is further configured with instructions in non-transitory memory, that when executed cause the controller to;

retrieve historic weather data and forecast weather data based on a location of the vehicle as determined by the on-board global positioning system.

9. The system of claim 7, where the controller is further configured with instructions in non-transitory memory, that when executed cause the controller to:

determine the ambient temperature change potential over the testing duration based on an integration of the filtered aggregated data set.

10. The system of claim 9, where the controller is further configured with instructions in non-transitory memory, that when executed cause the controller to:

determine a temperature gradient over the testing duration based on a comparison of the ambient temperature change potential and a fuel system temperature.

11. The system of claim 10, where the controller is further configured with instructions in non-transitory memory, that when executed cause the controller to:

initiate an engine-off natural vacuum test responsive to the determined temperature gradient being greater than a threshold.

12. The system of claim 7, where the controller is further configured with instructions in non-transitory memory, that when executed cause the controller to:

responsive to completing the engine-off natural vacuum test, retrieve recorded weather data for the testing duration; and

adjust a property of the low-pass filter based on a comparison of the retrieved recorded weather data and the ambient temperature change potential.

13. The system of claim 12, where the controller is further configured with instructions in non-transitory memory, that when executed cause the controller to:

validate a result of the engine-off natural vacuum test based on the retrieved recorded weather data.

14. A method for validating an evaporative emissions system leak test, comprising:

performing an engine-off natural vacuum test for a testing duration;

storing a result of the engine-off natural vacuum test at a controller;

responsive to a vehicle-on event, retrieving historic weather data for the testing duration from an off-board computing system; and

validating the result of the engine-off natural vacuum test based on the retrieved historic weather data.