Abstract: A method of controlling a gas turbine engine in a vehicle having an automatic system configured to control fuel flow includes determining whether a vehicle operator is requesting to manually control fuel. A pre-relinquishment value of an engine operating condition is determined while fuel flow is controlled by the automatic system. Fuel flow control is relinquished to the vehicle operator if the vehicle operator is requesting to manually control fuel flow and the pre-relinquishment value is within a predetermined range. A post-relinquishment value of the engine operating condition is determined while fuel flow is controlled by the vehicle operator. Fuel flow control is returned to the automatic system if the post-relinquishment value is not maintained within the predetermined range.

Abstract: Engines and methods for operating the engines are provided. The engine includes a means for limiting overspeed in flow communication with a turbine section flowpath, wherein the means for limiting overspeed is adapted to block a first portion of an airflow received along a first direction vector from flowing into an exhaust section flowpath and to redirect a second portion of the airflow received along the first direction vector or a portion of the blocked first portion of the airflow to flow along another direction vector that is closer to parallel with a longitudinal axis than the first direction vector.

Abstract: A method of controlling a gas turbine engine in a vehicle having an automatic system configured to control fuel flow includes determining whether a vehicle operator is requesting to manually control fuel. A pre-relinquishment value of an engine operating condition is determined while fuel flow is controlled by the automatic system. Fuel flow control is relinquished to the vehicle operator if the vehicle operator is requesting to manually control fuel flow and the pre-relinquishment value is within a predetermined range. A post-relinquishment value of the engine operating condition is determined while fuel flow is controlled by the vehicle operator. Fuel flow control is returned to the automatic system if the post-relinquishment value is not maintained within the predetermined range.

Abstract: Methods for maintaining a constant electrical output frequency in a turbogenerator with increased electrical loads are provided. The methods comprise biasing adjustable guide vanes of a compressor and/or a compressor bleed valve in response to the increased electrical load. A dual schedule system for carrying out the methods of the present invention is also provided.

Abstract: A system and method is provided for lightoff detection in a turbine engine that provides improved accuracy and consistency. The system and method use engine temperature and engine rotation speed sensor data to determine a first time interval during which the lightoff is estimated to have occurred. A peak gradient in the temperature sensor data within the first time interval and a peak gradient in the engine rotation sensor data within the first time interval are then determined. The temperature peak gradient time and the engine rotation peak gradient time are then used as boundaries to determine a narrowed time interval within the first time interval. The minimum gradient in the engine rotation sensor data in the narrowed time interval is determined, with the minimum gradient time in the engine rotation sensor data comprising an accurate estimate of lightoff time for the turbine engine.

Abstract: A system and method is provided for lightoff detection in a turbine engine that provides improved accuracy and consistency. The system and method use engine temperature and engine rotation speed sensor data to determine a first time interval during which the lightoff is estimated to have occurred. A peak gradient in the temperature sensor data within the first time interval and a peak gradient in the engine rotation sensor data within the first time interval are then determined. The temperature peak gradient time and the engine rotation peak gradient time are then used as boundaries to determine a narrowed time interval within the first time interval. The minimum gradient in the engine rotation sensor data in the narrowed time interval is determined, with the minimum gradient time in the engine rotation sensor data comprising an accurate estimate of lightoff time for the turbine engine.

Abstract: Methods for maintaining a constant electrical output frequency in a turbogenerator with increased electrical loads are provided. The methods comprise biasing adjustable guide vanes of a compressor and/or a compressor bleed valve in response to the increased electrical load. A dual schedule system for carrying out the methods of the present invention is also provided.

Abstract: A method of monitoring turbine engines used in aircraft from sensor signals from an engine for a predetermined set of engine characteristics. The signals are transmitted to a nonlinear engine model that predicts the output values for the given set of engine characteristics. The model generates residuals by calculating the difference between the actual values and the predicted values for each member of the set. The generated residuals are evaluated to estimate bounds of uncertainties as indicative of sensor noise. Incoming residuals from ongoing actual engine values are continuously tested against the bounds. A fault is signaled for each of the set of characteristics when a detected bound is exceeded. A computer is used to calculate the fault residual for each of the set of characteristics and the closest fault residual is selected as a diagnosed fault.

Abstract: A method of monitoring turbine engines used in aircraft from sensor signals from an engine for a predetermined set of engine characteristics. The signals are transmitted to a nonlinear engine model that predicts the output values for the given set of engine characteristics. The model generates residuals by calculating the difference between the actual values and the predicted values for each member of the set. The generated residuals are evaluated to estimate bounds of uncertainties as indicative of sensor noise. Incoming residuals from ongoing actual engine values are continuously tested against the bounds. A fault is signaled for each of the set of characteristics when a detected bound is exceeded. A computer is used to calculate the fault residual for each of the set of characteristics and the closest fault residual is selected as a diagnosed fault.

Abstract: A system and method that provides improved fault detection in turbine engines is disclosed. The fault detection system provides the ability to detect symptoms of engine faults based on a relatively limited number of engine parameters that are sampled relatively infrequently. The fault detection system includes a sensor data processor that receives engine sensor data during operation and augments the sensor data. The augmented data set is passed to a fuzzy logic inference system that determines the likelihood that a fault has occurred. The inference system output can then be passed to a diagnostic system where evaluation of the output may yield a detailed diagnostic result and a prediction horizon.