METHOD FOR ESTIMATION OF AT LEAST ONE ENGINE PARAMETER

• US 20110118950A1
• Filed: 12/20/2010
• Published: 05/19/2011
• Est. Priority Date: 05/12/2006
• Status: Active Grant

• Current Assignee: The United States Of America As Represented By The Secretary Of The Army
• Original Assignee: United States Secretary of the Army
• Inventors: LITT, Jonathan S.
• Granted Patent: US 8,185,292 B2
• Time in Patent Office: Days
• US Class Current: 701/100
• CPC Class Codes: G01M 15/14 Testing gas-turbine engines or jet-propulsion engines

Abstract

A system comprising determination of tuning parameters enabling optimal estimation of unmeasured engine outputs, e.g., thrust. The level of degradation of engine performance is generally described by unmeasurable health parameters related to each major engine component. Accurate thrust reconstruction depends upon knowledge of these health parameters, but there are usually too few sensors to estimate their values. A set of tuning parameters is determined which accounts for degradation by representing the overall effect of the larger set of health parameters as closely as possible in a least squares sense. The method utilizes the singular value decomposition of a matrix to generate a tuning parameter vector of low enough dimension that it can be estimated by a Kalman filter. Generation of a tuning vector specifically takes into account the variables of interest. The tuning parameters facilitate matching of both measured and unmeasured engine outputs, as well as state variables.

Claims

1. A method of measuring the health of an engine comprising h number of parameters, said method comprising:

estimating unmeasurable (auxiliary) outputs of an engine;

measuring engine parameters in a number less than said h number of parameters and estimating the impact of health deterioration on outputs of said engine.

2. The method of claim 1, wherein the engine is a turbofan engine.

3. The method of claim 2, wherein the auxiliary parameter that is not measured is one selected from the group consisting of gross thrust and net thrust.

4. The method of claim 1, wherein the tuning vector is not a subset of the health parameters.

5. The method of claim 1, wherein the tuning vector is represented by q and its estimate of value corresponds to the relationship expressed as:

6. The method of claim 5, wherein the measured parameters are measured by sensors y, and further selecting a k number of values, where k is equal to the number of sensors less the number of zero eigenvalues in the original system.

7. A method of determining faults in a turbofan engine where the fault is not in a measured parameter, by estimating the vector q of claim 5 a number of times and determining abrupt shifts in the tuner as an indication of a fault.

8-15. -15. (canceled)