Water-in-Fuel Detection Using Duty Cycle Calculation

• US 20090048728A1
• Filed: 08/16/2007
• Published: 02/19/2009
• Est. Priority Date: 08/16/2007
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Nunn, Janette Marie, Stuber, Suzanne, Rollinger, John Eric, Waskiewicz, David Chester
• Granted Patent: US 8,781,673 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: F02D 41/0025 Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
• CPC Class Codes: F02M 37/28 with means activated by the presence of water, e.g. alarms or means for automatic drainage
• CPC Class Codes: F02M 37/30 characterised by heating means
• CPC Class Codes: F02M 37/32 characterised by filters or filter arrangements

Abstract

A method for operating a vehicle having a fuel system that may be contaminated with water is described. The method includes, adjusting an operating parameter in response to a relative amount of high and low readings from a water-in-fuel sensor coupled in the fuel system.

Claims

1. A method for operating a vehicle having a fuel system that may be contaminated with water, the method comprising:

adjusting an operating parameter in response to a relative amount of high and low readings from a water-in-fuel sensor coupled in the fuel system.

2. The method of claim 1 where the operating parameter includes a diagnostic code.

3. The method of claim 2 where the diagnostic code is adjusted in response to a duty cycle of high and low readings of the sensor during transient fuel system conditions.

4. The method of claim 3 where the transient fuel system conditions include fuel sloshing conditions.

5. The method of claim 4 where the duty cycle is determined when vehicle speed is above a threshold value.

6. The method of claim 5 wherein the relative amount includes a first relative amount during the transient fuel system conditions and a second relative amount during static conditions, where the diagnostic code is adjusted in response to both the first and second relative amounts.

7. The method of claim 1 where the first and second relative amounts include a plurality of readings during the transient and static conditions.

8. A system for a vehicle, comprising:

a fuel system having a fuel-water separator;

a multi-prong water-in-fuel sensor coupled in the separator, the sensor providing a first output when in contact with water and a second output when in contact with fuel;

a diagnostic system coupled in the vehicle for receiving the sensor outputs, and adjusting an operating parameter indicative during agitation based on a relative ratio of the first and second outputs.

9. The system of claim 8 where the separator is a horizontally mounted separator.

10. The system of claim 8 where the diagnostic system sets a diagnostic code based on a determination of an amount of water in the system, where the amount of water is determined in response to the relative ratio.

11. The system of claim 10 where the agitation includes non-idle vehicle conditions.

12. The system of claim 8 where the diagnostic system further adjusts the operating parameter responsive to a second relative ratio of the first and second outputs during idle conditions.

13. The system of claim 12 where the sensor provides a binary voltage signal.

14. The system of claim 13 where the relative ratio includes a duty cycle.

15. The system of claim 14 where the sensor senses conductivity of fluid in the fuel-water separator.

16. A method for determining the presence of water in fuel within a liquid containing fuel-water separator, comprising:

adjusting a diagnostic code in response to a first duty cycle based on a voltage signal generated by a multi-prong water-in-fuel sensor coupled in the fuel-water separator during high agitation conditions, and in response to a second duty cycle based on the voltage signal during low agitation events, the sensor sensing conductivity of the liquid, where the diagnostic code is set to indicate the presence of water in fuel when either the first or second duty cycles fall outside of respective ranges, and where the diagnostic code is re-set to indicate acceptable operation only when the first duty cycle falls within the respective range.