Vehicle method for barometric pressure identification

• US 9,945,309 B2
• Filed: 05/03/2016
• Issued: 04/17/2018
• Est. Priority Date: 10/22/2012
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Bohr, Scott A., Pearce, Russell Randall, Peters, Mark W., Jentz, Robert Roy, Dudar, Aed M.
• Primary Examiner(s): Kwon, John
• Application Number:
  US15/145,656
• Publication Number:
  US 20160245200A1
• Time in Patent Office: 714 Days
• Field of Search: 701101, 701107, 701114, 123434, 123435, 123677, 123465, 123462, 123FOR 107, 123FOR 120
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2710/0616 Position of fuel or air injector
• CPC Class Codes: F02D 41/0037 for diagnosing the engine diagnosis of purge control systems F02M25/0809
• CPC Class Codes: F02M 25/0854 Details of the absorption canister
• CPC Class Codes: F02N 2200/121 Atmospheric pressure, e.g. for determination of geodetic height
• CPC Class Codes: F02N 2200/122 Atmospheric temperature
• CPC Class Codes: Y10S 903/904 Component specially adapted for hev

Abstract

A vehicle method for barometric pressure identification, including adjusting engine operation responsive to barometric pressure, the barometric pressure based on a pressure change at a sector of the fuel system when the sector is sealed with the vehicle travelling. The method may utilize a pressure change at the sealed sector of the fuel system, such as a sealed fuel tank, to identify barometric pressure, even with the engine off for extended durations of vehicle travel. As such, in a hybrid-vehicle application, including during hill descents in which the engine is maintained off, barometric pressure can still be updated.

Claims

1. A vehicle method, comprising:

adjusting engine operation responsive to barometric pressure, the barometric pressure determined based on a pressure change in a sector of a fuel system when the sector is sealed with a vehicle travelling, and wherein a leak is indicated in the fuel system based on a ratio of pressure changes in each of the sealed sector and another sealed sector of the fuel system.

2. The method of claim 1, wherein the barometric pressure is further determined based on a pressure change in the another sector of the fuel system when the another sector is sealed with the vehicle traveling.

3. The method of claim 1, wherein the vehicle traveling includes descending a hill with an engine shut off.

4. The method of claim 2, wherein the barometric pressure is further determined based on the pressure change in the another sector of the fuel system when both pressure changes change at a predictable ratio, and the leak is indicated when the ratios change independently.

5. The method of claim 1, wherein the sector of the fuel system is a fuel tank, and the another sector is an evaporative leak check module (ELCM).

6. The method of claim 5, wherein the fuel tank is sealed by closing a fuel tank isolation valve.

7. The method of claim 1, wherein one of the sectors of the fuel system is a fuel vapor canister.

8. The method of claim 7, wherein the fuel vapor canister is sealed by closing a fuel tank isolation valve, a canister purge valve and a canister vent valve.

9. The method of claim 1, wherein the barometric pressure is further based on a temperature change over the pressure change and wherein the barometric pressure is determined when the temperature change is less than a threshold during the pressure change.

10. The method of claim 2, wherein a fuel tank is sealed throughout the pressure change, without becoming unsealed during the pressure change.

11. The method of claim 1, wherein the pressure change is greater than a threshold pressure change.

12. The method of claim 1, wherein the vehicle is a hybrid vehicle.

13. The method of claim 1, wherein the vehicle is a plug-in hybrid-electric vehicle.

14. The method of claim 1, wherein an engine is at rest during the pressure change.

15. The method of claim 1, wherein an engine includes a mass airflow sensor, without a pressure sensor in an intake manifold of the engine.

16. The method of claim 1, wherein the pressure change occurs over a threshold duration traveled by the vehicle, and where engine operation includes engine spark timing and engine air-fuel ratio.

17. The method of claim 16, wherein the threshold duration is a time period.

18. The method of claim 16, wherein the threshold duration is a distance measured by wheel sensors.

19. The method of claim 1, wherein the sector of the fuel system is sealed from an engine and an ambient environment during the pressure change.