Vehicle method for barometric pressure identification

• US 10,100,758 B2
• Filed: 03/15/2018
• Issued: 10/16/2018
• 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:
  US15/922,079
• Publication Number:
  US 20180202376A1
• Time in Patent Office: 215 Days
• Field of Search: 701101, 701107, 701114, 701106, 701112, 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 of a vehicle, comprising:

adjusting engine operation responsive to barometric pressure, the barometric pressure estimated based on a relative pressure change in a sealed fuel system over a threshold distance traveled by the vehicle with an engine remaining deactivated at rest and a fuel pump deactivated; and

indicating a leak based on the relative pressure change.

2. The vehicle method of claim 1, wherein indicating the leak includes indicating a leak in the sealed fuel system responsive to the relative pressure change and wherein when the engine remains deactivated at rest, the vehicle is propelled by a motor and not by the engine.

3. The vehicle method of claim 1, wherein the relative pressure change in the sealed fuel system is a relative pressure change of a sealed fuel tank of the sealed fuel system and wherein the barometric pressure is further estimated based on a relative pressure change of a sealed evaporative leak check module (ELCM) of the sealed fuel system.

4. The vehicle method of claim 3, wherein the barometric pressure is further estimated based on the relative pressure change of the sealed ELCM when both the relative pressure change of the sealed fuel tank and the relative pressure change of the sealed ELCM change at a predictable ratio, and wherein the indicating the leak includes indicating the leak in response to the ratios changing independently.

5. The vehicle method of claim 3, wherein the fuel tank is sealed by closing a fuel tank isolation valve.

6. The vehicle method of claim 3, wherein the ELCM is sealed by closing a canister purge valve, a canister vent valve, and a fuel tank isolation valve.

7. The vehicle method of claim 3, wherein the sealed fuel tank remains sealed throughout the relative pressure change, without becoming unsealed during the relative pressure change.

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

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

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

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

12. The vehicle method of claim 1, wherein the engine includes a mass airflow sensor, without a pressure sensor in an intake manifold of the engine and further comprising adjusting engine operation responsive to barometric pressure, the barometric pressure estimated based on an output of the mass airflow sensor during operation of the vehicle when the engine is activated and a position of a throttle is greater than a threshold position.

13. The vehicle method of claim 1, wherein adjusting engine operation includes adjusting engine spark timing and engine air-fuel ratio.

14. The vehicle method of claim 1, wherein the threshold distance is measured by wheel sensors.

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

16. A system for a vehicle, comprising:

a controller with computer readable instructions stored on non-transitory memory that when executed during operation of the vehicle, while the vehicle is being propelled by a motor and not an engine of the vehicle and while a fuel system of the vehicle is sealed and a fuel pump in the fuel system is deactivated, cause the controller to;

estimate barometric pressure based on a relative pressure change in the sealed fuel system of the vehicle over a threshold distance traveled by the vehicle;

adjust engine operation responsive to the estimated barometric pressure; and

indicate a leak in the sealed fuel system based on the relative pressure change.

17. The system of claim 16, wherein the computer readable instructions further cause the controller to indicate the leak in the sealed fuel system in response to the estimated barometric pressure based on the relative pressure change being outside of an expected range of barometric pressure values, where the expected range of barometric pressure values is based on one or more of previous inferred barometric pressure values, GPS data, inferred altitude estimates, and internal and external temperatures.

18. The system of claim 16, wherein the vehicle is a hybrid electric vehicle and wherein the engine includes a mass airflow sensor, without a pressure sensor in an intake manifold of the engine.

19. A vehicle method of a vehicle, comprising:

indicating a leak in a fuel system in response to a first relative pressure change of a sealed fuel tank in the fuel system and a second relative pressure change of a sealed evaporative leak check module (ELCM) in the fuel system, where the first relative pressure change and the second relative pressure change are determined over a threshold distance traveled by the vehicle while an engine is deactivated at rest and a fuel pump is deactivated; and

adjusting engine operation based on barometric pressure, the barometric pressure estimated based on the first relative pressure change and the second relative pressure change.

20. The vehicle method of claim 19, wherein indicating the leak in the fuel system includes indicating the leak in the fuel system in response to the first relative pressure change and the second relative pressure change changing at independent ratios.