VEHICLE METHOD FOR BAROMETRIC PRESSURE IDENTIFICATION

• US 20140114550A1
• Filed: 10/22/2012
• Published: 04/24/2014
• 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.
• Granted Patent: US 9,328,678 B2
• Time in Patent Office: Days
• US Class Current: 701/102
• 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 based on a pressure change in a sector of the fuel system when the sector is sealed with the vehicle travelling.

2. The method of claim 1 wherein the sector of the fuel system is a fuel tank.

3. The method of claim 2 wherein the fuel tank is sealed by closing a fuel tank isolation valve.

4. The method of claim 1 wherein the sector of the fuel system is a fuel vapor canister.

5. The method of claim 4 wherein the sector of the fuel vapor canister is sealed by closing a fuel tank isolation valve, a canister purge valve and a canister vent valve.

6. The method of claim 1 wherein the barometric pressure is further based on a temperature change over the pressure change.

7. The method of claim 6 wherein the barometric pressure is determined when the temperature change is less than a threshold during the pressure change.

8. The method of claim 1 wherein the fuel tank is sealed throughout the pressure change, without become unsealed during the pressure change.

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

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

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

12. The method of claim 1 wherein the engine is at rest during the pressure change.

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

14. 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.

15. The method of claim 14 wherein the threshold duration is a time period.

16. The method of claim 14 wherein the threshold duration is a distance measured by wheel sensors.

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

18. A vehicle method, 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 the engine remaining deactivated at rest and a fuel pump deactivated.

19. A system for controlling a vehicle propulsion system in a vehicle comprising:

an engine;

a mass airflow sensor;

a fuel tank having a relative pressure sensor;

a fuel tank isolation valve; and

a controller having instruction executable to;

during a first mode with the engine spinning, estimate barometric pressure based on the mass airflow sensor, engine speed, and throttle position; and

during a second mode with the engine off, estimate barometric pressure based on a change in the relative pressure in the fuel tank with the tank sealed by the fuel tank isolation valve; and

adjust engine operation based on the estimated barometric pressures.