LEAKAGE DETECTION AND FLUID LEVEL PROGNOSTICS FOR AIRCRAFT HYDRAULIC SYSTEMS

• US 20100030496A1
• Filed: 07/30/2008
• Published: 02/04/2010
• Est. Priority Date: 07/30/2008
• Status: Active Grant

• Current Assignee: Yabora Industria Aeronautica S.A. (Embraer S.A.)
• Original Assignee: Embraer S.A.
• Inventors: Vianna, Wlamir Olivares Loesch
• Granted Patent: US 7,962,295 B2
• Time in Patent Office: Days
• US Class Current: 702/51
• CPC Class Codes: B64D 2045/0085 Devices for aircraft health monitoring, e.g. monitoring flutter or vibration
• CPC Class Codes: B64D 41/00 Power installations for auxiliary purposes
• CPC Class Codes: B64D 43/00 Arrangements or adaptations of instruments arrangements of cameras B64D47/08; aeronautical measuring instruments per se G01C
• CPC Class Codes: F15B 1/26 Supply reservoir or sump assemblies
• CPC Class Codes: F15B 19/005 Fault detection or monitoring
• CPC Class Codes: F15B 20/005 Leakage; Spillage; Hose burst
• CPC Class Codes: F15B 2211/6303 using input signals
• CPC Class Codes: F15B 2211/6306 representing a pressure
• CPC Class Codes: F15B 2211/6343 representing a temperature
• CPC Class Codes: F15B 2211/857 Monitoring of fluid pressure systems
• CPC Class Codes: F15B 2211/8636 Circuit failure, e.g. valve or hose failure

Abstract

A method for detecting and predicting total hydraulic fluid level for aircraft hydraulic systems includes determining an estimated value for a parameter indicative of total fluid level or mass. Each new value is combined with an historical indication (e.g., from previous flights) to provide a prediction for the future value of total quantity indication. With the same combination, one can provide an estimated value for total system leakage or level loss. An alert can be generated if hydraulic fluid level or mass is predicted to fall below a predetermined level.

Claims

1. A method of detecting and predicting hydraulic fluid leakage for an aircraft hydraulic system comprising:

sensing at least one parameter associated with said hydraulic system;

determining, at least in part in response to said sensed parameter, an estimated value indicative of total fluid level or mass;

combining said estimated value with at least some historical values to provide a prediction for the future value of total quantity indication; and

displaying an indication at least in part associated with said leakage.

2. The method of claim 1 wherein said sensing comprises sensing fluid quantity.

3. The method of claim 1 wherein said sensing comprises sensing fluid temperature.

4. The method of claim 1 further including providing an estimated value for total system leakage or level loss.

5. The method of claim 1 further including providing an alert based on comparison between predicted value and a threshold.

6. The method of claim 1 wherein said combining includes curve fitting.

7. The method of claim 1 wherein said combining includes second order polynomial curve fitting.

8. The system of claim 1 wherein said display provides a graphical user interface that graphically represents estimated total system leakage of said hydraulic fluid, expected time to indication of total hydraulic fluid mass reaches a defined threshold and uses different colors to indicate alert state.

9. The method of claim 1 wherein said displaying includes providing a two-dimensional graphical display that plots historical indication of total hydraulic fluid mass against time.

10. The method of claim 1 wherein said determining includes estimating fluid density from fluid temperature sensor indication and multiplying by the sum of quantity gauge sensor indication and system volume estimated value.

11. The method of claim 1 wherein said determining includes applying a PCA estimated constant.

12. An aircraft hydraulic system comprising:

a fluid reservoir;

a device the pressurizes fluid from said reservoir;

at least one hydraulic line that delivers said pressurized fluid supplied by said fluid reservoir to at least one pressure consumer;

at least one sensor that senses at least one parameter associated with said pressurized fluid and/or said reservoir;

an estimator that determines, at least in part in response to said sensed parameter, an estimated value indicative of total fluid level or mass;

a combiner that combines said estimated value with an historical indication to provide a prediction for the future value of total quantity indication; and

a display that displays an indication at least in part associated with said total quantity indication.

13. The system of claim 12 wherein said estimator includes means for generating a PCA estimated constant.

14. The system of claim 12 wherein said estimator includes means for generating a system volume estimated value.

15. The system of claim 12 wherein said combiner includes a curve fitting.

16. The system of claim 12 wherein said display provides a graphical user interface that graphically represents estimated total system leakage of said hydraulic fluid and uses different colors to indicate alert state.

17. A method of detecting and predicting hydraulic fluid leakage for an aircraft hydraulic system comprising:

during a current flight, sensing at least one parameter associated with the aircraft hydraulic system;

determining, at least in part in response to said sensed parameter, an estimated value indicative of total fluid level or mass;

combining said estimated value with at least some historical values from previous flights to provide a prediction for the future value of total quantity indication; and

displaying an alert if said prediction indicates that sufficient leakage will occur to cause hydraulic fluid level or mass to fall below a predetermined level.