Abstract: A method from discriminating between spurious and genuine surges in a gas turbine engine is provided which includes the steps of receiving an engine speed signal over a global engine surge investigation region that includes a plurality of operating regions (e.g. speed bands) in which engine surges can occur, identifying a specific operating region in which an engine surge event occurs, incrementing a surge counter corresponding to the operating region in which the engine surge event occurred, identifying the operating regions in which no engine surge event occurred, decrementing a surge counter corresponding to each operating region in which no engine surge event occurred; enabling a surge avoidance signal when the magnitude of the surge counter for a particular operating region has reached a predetermined value; and adapting an engine acceleration schedule in the operating region corresponds to the surge avoidance signal.

Abstract: A method from discriminating between spurious and genuine surges in a gas turbine engine is provided which includes the steps of receiving an engine speed signal over a global engine surge investigation region that includes a plurality of operating regions (e.g. speed bands) in which engine surges can occur, identifying a specific operating region in which an engine surge event occurs, incrementing a surge counter corresponding to the operating region in which the engine surge event occurred, identifying the operating regions in which no engine surge event occurred, decrementing a surge counter corresponding to each operating region in which no engine surge event occurred; enabling a surge avoidance signal when the magnitude of the surge counter for a particular operating region has reached a predetermined value; and adapting an engine acceleration schedule in the operating region corresponds to the surge avoidance signal.

Abstract: Fuel control systems for use with a gas turbine engines which accounts for real-time thermodynamic engine effects when attempting to match or track the NDOTActual rate to the NDOTDemand rate. The fuel control system includes a mechanism for measuring several engine operating parameters and a mechanism for determining an initial engine fuel demand based on the measured engine operating parameters. The control system further includes a mechanism for estimating, during engine operation and based on the measured operating parameters, the amount of heat transferred between fuel combustion gases and the engine metal and estimating an effective fuel flow adjustment based therefrom. The control system disclosed herein also includes a mechanism for determining a final engine fuel demand based on the initial predicted engine fuel demand and the estimated effective fuel flow adjustment.

Abstract: A fuel metering unit for controlling a variable displacement pump including a main metering valve in fluid communication with the pump for metering an output of the pump, a pressure regulator in fluid communication with the metering valve to create a spill return and a control valve in fluid communication with the pressure regulator and the pump for regulating the spill return flow so the spill return flow is maintained substantially constant at a low level to minimize the heat generated by recirculation by setting a displacement of the pump.

Abstract: A system for performing feed-forward anticipation of rotor torque demand on a helicopter engine is disclosed which includes a flight control computer adapted and configured to predict the total torque required at the main and tail rotors of the helicopter, and an engine fuel control system adapted and configured to compute the rate of change of the total torque, convert the rate of change of the total torque to an engine acceleration/deceleration rate, and obtain a demanded engine acceleration/deceleration rate therefrom.

Abstract: Disclosed herein is a “real time” Time Limited Dispatch (TLD) fault management system and method for evaluating the operational suitability of an engine's electronic control system. The TLD system disclosed herein uses a software algorithm to compute or predict the probability of mission success for a given upcoming mission length (e.g., two hours) and the time remaining to repair control system faults before dispatch is disallowed or the flight suspended, regardless of the probability of success.

Abstract: A fuel metering unit including a pump having a rotor with a plurality of slots. The pump also includes a pivotally movable cam ring coaxially arranged with respect to the rotor. Vanes are slideably disposed in the slots for maintaining contact with the cam ring during movement thereof. A servovalve has a motor and nozzles operatively connected to the pump such that increased flow through the first nozzle pivots the ring of the pump toward maximum while increased flow through the second nozzle pivots the ring toward minimum. An arm extends between the nozzles for varying fluid flow therethrough. The arm couples to the motor such that the motor moves the arm. A flow meter connects to the pump and an end of the arm for applying a force against the arm to assist in maintaining position of the arm.

Abstract: A fuel metering unit for controlling a variable displacement pump including a main metering valve in fluid communication with the pump for metering an output of the pump, a pressure regulator in fluid communication with the metering valve to create a spill return and a control valve in fluid communication with the pressure regulator and the pump for regulating the spill return flow so the spill return flow is maintained substantially constant at a low level to minimize the heat generated by recirculation by setting a displacement of the pump.

Abstract: A fuel metering unit including a pump having a rotor with a plurality of slots. The pump also includes a pivotally movable cam ring coaxially arranged with respect to the rotor. Vanes are slideably disposed in the slots for maintaining contact with the cam ring during movement thereof. A servovalve has a motor and nozzles operatively connected to the pump such that increased flow through the first nozzle pivots the ring of the pump toward maximum while increased flow through the second nozzle pivots the ring toward minimum. An arm extends between the nozzles for varying fluid flow therethrough. The arm couples to the motor such that the motor moves the arm. A flow meter connects to the pump and an end of the arm for applying a force against the arm to assist in maintaining position of the arm.

Abstract: The subject invention is directed to a new and useful method of detecting in-range engine sensor faults for a gas turbine engine associated with a helicopter. The method includes the steps of computing engine shaft horsepower for a plurality of engine sensor, computing a first mean horsepower from the plurality of engine sensors, computing the horsepower deviation from the first mean horsepower for each engine sensor, computing a horsepower deviation ratio for each engine sensor relative to all other engine sensors, disabling the engine sensor with the largest deviation from the first mean horsepower, computing a second mean horsepower, computing the horsepower deviation from the second mean horsepower for each engine sensor, re-computing the horsepower deviation ratio for each engine sensor relative to all other engine sensors, comparing the horsepower deviation ratios to predefined limits, and declaring a sensor fault if the horsepower deviation ratio for an engine sensor exceeds a predefined limit.

Abstract: Fuel control systems for use with a gas turbine engines which accounts for real-time thermodynamic engine effects when attempting to match or track the NDOTActual rate to the NDOTDemand rate. The fuel control system includes a mechanism for measuring several engine operating parameters and a mechanism for determining an initial engine fuel demand based on the measured engine operating parameters. The control system further includes a mechanism for estimating, during engine operation and based on the measured operating parameters, the amount of heat transferred between fuel combustion gases and the engine metal and estimating an effective fuel flow adjustment based therefrom. The control system disclosed herein also includes a mechanism for determining a final engine fuel demand based on the initial predicted engine fuel demand and the estimated effective fuel flow adjustment.

Abstract: Disclosed herein is a “real time” Time Limited Dispatch (TLD) fault management system and method for evaluating the operational suitability of an engine's electronic control system. The TLD system disclosed herein uses a software algorithm to compute or predict the probability of mission success for a given upcoming mission length (e.g., two hours) and the time remaining to repair control system faults before dispatch is disallowed or the flight suspended, regardless of the probability of success.

Abstract: Fuel control systems for use with a gas turbine engines which accounts for real-time thermodynamic engine effects when attempting to match or track the NDOTActual rate to the NDOTDemand rate. The fuel control system includes a mechanism for measuring several engine operating parameters and a mechanism for determining an initial engine fuel demand based on the measured engine operating parameters. The control system further includes a mechanism for estimating, during engine operation and based on the measured operating parameters, the amount of heat transferred between fuel combustion gases and the engine metal and estimating an effective fuel flow adjustment based therefrom. The control system disclosed herein also includes a mechanism for determining a final engine fuel demand based on the initial predicted engine fuel demand and the estimated effective fuel flow adjustment.

Abstract: A fuel metering unit including a pump having a rotor with a plurality of slots. The pump also includes a pivotally movable cam ring coaxially arranged with respect to the rotor. Vanes are slideably disposed in the slots for maintaining contact with the cam ring during movement thereof. A servovalve has a motor and nozzles operatively connected to the pump such that increased flow through the first nozzle pivots the ring of the pump toward maximum while increased flow through the second nozzle pivots the ring toward minimum. An arm extends between the nozzles for varying fluid flow therethrough. The arm couples to the motor such that the motor moves the arm. A flow meter connects to the pump and an end of the arm for applying a force against the arm to assist in maintaining position of the arm.

Abstract: The subject invention is directed to a new and useful method of detecting in-range engine sensor faults for a gas turbine engine associated with a helicopter. The method includes the steps of computing engine shaft horsepower for a plurality of engine sensor, computing a first mean horsepower from the plurality of engine sensors, computing the horsepower deviation from the first mean horsepower for each engine sensor, computing a horsepower deviation ratio for each engine sensor relative to all other engine sensors, disabling the engine sensor with the largest deviation from the first mean horsepower, computing a second mean horsepower, computing the horsepower deviation from the second mean horsepower for each engine sensor, re-computing the horsepower deviation ratio for each engine sensor relative to all other engine sensors, comparing the horsepower deviation ratios to predefined limits, and declaring a sensor fault if the horsepower deviation ratio for an engine sensor exceeds a predefined limit.

Abstract: A system for performing feed-forward anticipation of rotor torque demand on a helicopter engine is disclosed which includes a flight control computer adapted and configured to predict the total torque required at the main and tail rotors of the helicopter, and an engine fuel control system adapted and configured to compute the rate of change of the total torque, convert the rate of change of the total torque to an engine acceleration/deceleration rate, and obtain a demanded engine acceleration/deceleration rate therefrom.

Abstract: A fuel metering unit including a pump having a rotor with a plurality of slots. The pump also includes a pivotally movable cam ring coaxially arranged with respect to the rotor. Vanes are slideably disposed in the slots for maintaining contact with the cam ring during movement thereof. A servovalve has a motor and nozzles operatively connected to the pump such that increased flow through the first nozzle pivots the ring of the pump toward maximum while increased flow through the second nozzle pivots the ring toward minimum. An arm extends between the nozzles for varying fluid flow therethrough. The arm couples to the motor such that the motor moves the arm. A flow meter connects to the pump and an end of the arm for applying a force against the arm to assist in maintaining position of the arm.

Abstract: A fuel metering unit including a pump having a rotor with a plurality of slots. The pump also includes a pivotally movable cam ring coaxially arranged with respect to the rotor. Vanes are slideably disposed in the slots for maintaining contact with the cam ring during movement thereof. A servovalve has a motor and nozzles operatively connected to the pump such that increased flow through the first nozzle pivots the ring of the pump toward maximum while increased flow through the second nozzle pivots the ring toward minimum. An arm extends between the nozzles for varying fluid flow therethrough. The arm couples to the motor such that the motor moves the arm. A flow meter connects to the pump and an end of the arm for applying a force against the arm to assist in maintaining position of the arm.

Abstract: Fuel control systems for use with a gas turbine engines which accounts for real-time thermodynamic engine effects when attempting to match or track the NDOTActual rate to the NDOTDemand rate. The fuel control system includes a mechanism for measuring several engine operating parameters and a mechanism for determining an initial engine fuel demand based on the measured engine operating parameters. The control system further includes a mechanism for estimating, during engine operation and based on the measured operating parameters, the amount of heat transferred between fuel combustion gases and the engine metal and estimating an effective fuel flow adjustment based therefrom. The control system disclosed herein also includes a mechanism for determining a final engine fuel demand based on the initial predicted engine fuel demand and the estimated effective fuel flow adjustment.

Abstract: A method of discriminating between spurious and genuine surges in a gas turbine engine is disclosed which includes the steps of receiving an engine speed signal over a global engine surge investigation region having a plurality of temporal regions in which engine surge events can occur, identifying a specific temporal region in which an engine surge event occurs, incrementing a surge counter corresponding to the temporal region in which the engine surge event occurred by a magnitude of two, identifying the temporal regions in which no engine surge event occurred, decrementing a surge counter corresponding to each temporal region in which no engine surge event occurred by a magnitude of one; and enabling a surge avoidance flag when the magnitude of the surge counter has reached a predetermined value.