System and methods for fuel level inference

Patent metadata

Field	Value
Publication number	US-9546894-B2
Application number	US-201414226498-A
Country	US
Kind code	B2
Filing date	Mar 26, 2014
Priority date	Mar 26, 2014
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

A method for a fuel system, comprising: monitoring a fuel tank pressure during a refueling event; determining a fuel flow rate based on a steady-state portion of the monitored fuel tank pressure; and indicating an amount of fuel added to a fuel tank based on the fuel flow rate. In this way, a fuel tank fill level can be determined following a refueling event, even in a scenario where the fuel level indicator is stuck or malfunctioning.

First claim

The invention claimed is:

1. A method, comprising:
before a refueling event, opening an isolation tank valve and a canister vent valve via respective actuators;
maintaining the isolation tank valve and the canister vent valve open during the refueling event; and
indicating, to a vehicle operator, a fuel level of a fuel tank based on a steady-state fuel tank pressure during the refueling event.

2. The method of claim 1 , where the fuel level is a liquid fuel level.

3. The method of claim 2 , where the fuel level of the fuel tank is further based on a duration of the refueling event.

4. The method of claim 3 , wherein a time-to-full duration is determined based on the steady-state fuel tank pressure.

5. The method of claim 2 , wherein a fuel flow rate is determined based on the steady-state fuel tank pressure.

6. The method of claim 5 , wherein the fuel flow rate is a liquid fuel flow rate.

7. The method of claim 1 , wherein the fuel level of the fuel tank is further based on a residual fuel level determined prior to commencement of the refueling event.

8. The method of claim 7 , where the residual fuel level is determined based on an amount of fuel consumed following a full-tank event.

9. A method for a fuel system, comprising:
monitoring a fuel tank pressure during a refueling event via a sensor;
determining a fuel flow rate based on a steady-state portion of the monitored fuel tank pressure;
indicating an amount of fuel added to a fuel tank based on the fuel flow rate;
determining an initial fuel tank fill level prior to the refueling event; and
indicating to an operator a fuel tank fill level based on a sum of the initial fuel tank fill level and the amount of fuel added.

10. The method of claim 9 , where determining the amount of fuel added includes integrating the fuel flow rate over a duration of the refueling event.

11. The method of claim 10 , where the duration of the refueling event is determined by an initial pressure change and a final pressure change.

12. The method of claim 11 , where the final pressure change includes an increase in fuel pressure above the steady-state portion of the monitored fuel tank pressure.

13. The method of claim 9 , where determining the initial fuel tank fill level prior to the refueling event further comprises:
determining the fuel tank fill level following a previous refueling event; and
determining an amount of fuel consumed following the previous refueling event.

14. The method of claim 13 , further comprising:
indicating a user to fill the fuel tank when the fuel tank fill level following the previous refueling event is indeterminate.

15. A fuel system for a vehicle, comprising:
a fuel tank configured to receive and store a liquid fuel;
a fuel tank pressure sensor coupled to the fuel tank; and
a controller configured with instructions stored in non-transitory memory, that when executed, cause the controller to:
determine a fuel tank fill level prior to a refueling event;
monitor a fuel tank pressure during the refueling event;
determine a steady-state fuel tank pressure from the monitored fuel tank pressure;
determine a duration of the refueling event;
determine an amount of liquid fuel added based on the steady-state fuel tank pressure and further based on the duration of the refueling event; and
indicate to an operator a fuel tank fill level following the refueling event based on a sum of the amount of liquid fuel added and the fuel tank fill level prior to the refueling event.

16. The fuel system of claim 15 , where the controller further comprises:
lookup tables stored in non-transitory memory for determining a fuel flow rate based on the steady-state fuel tank pressure.

17. The fuel system of claim 15 , where the controller further comprises:
lookup tables stored in non-transitory memory for determining a time-to-full duration based on the steady-state fuel tank pressure.

18. The fuel system of claim 15 , where the controller is further configured with instructions stored in non-transitory memory, that when executed, cause the controller to:
indicate a full fuel tank based on an automatic shut-off event.

Assignees

• Ford Global Tech Llc

Inventors

• Dudar Aed M

Classifications

• B60K2015/03256

  characterised by special valves, the mounting thereof · CPC title

• G01F23/18 Primary

  Indicating, recording or alarm devices actuated electrically · CPC title

• B60K2015/03217

  Fuel level sensors · CPC title

• G01F25/0061

  Physics · mapped topic

• B60K2015/0319

  with electronic systems, e.g. for controlling fuelling or venting · CPC title