Abstract:
A method of adjusting a setpoint value of at least one parameter that has an influence on thrust of a gas turbine engine propelling an aircraft during a stage of flight of the aircraft, the method including: obtaining a current value of at least one operating variable of the engine; extracting from a pre-established table a decrement value for the at least one parameter associated with the current value of the at least one operating variable of the engine; and adjusting the setpoint value of the at least one parameter by applying thereto the decrement value extracted from the table.
Abstract:
In a fuel control system for turbine engines, it is beneficial to provide a minimum fuel signal which prevents the fuel demand of the turbine engine from being decreased below a lower limit which can cause flameout or extinction. The fuel control system of the present invention provides an electronic circuit that includes a portion which dynamically determines the minimum fuel demand of the turbine engine during operation. A circuit is provided to compare the power output of the turbine engine to a predetermined threshold magnitude. The no-load or low-load minimum fuel demand level is continually monitored until the power output of the turbine engine exceeds the predetermined threshold magnitude at which time the stored value of fuel demand is inhibited from being subsequently changed. During later operation of the turbine engine, the stored value of minimum fuel demand is provided to a most fuel bus to operate as a minimum limit of fuel demand for the turbine engine. A temperature compensation device adjusts the minimum fuel demand in response to temperature changes that can occur after the minimum fuel demand is stored.
Abstract:
A limited authority system for controlling engine performance in accordance with energy or thrust requirements in response to engine parameters which is capable of operating in a number of control modes.
Abstract:
Pushbutton controls are provided for the power management of a turbine powered aircraft; and these pushbuttons may be mounted on the aircraft pilot's control handwheel. The turbine engine has a maximum rated permissible rotational speed which initially increases with increasing air temperature and with increasing altitude or reduced pressure; and has an absolute maximum limitation, with this maximum permissible rotational speed decreasing at increasing temperatures starting at about 10 or 15 degrees below zero, centigrade; and these limitations are reduced when supplemental equipment such as de-icing equipment is turned on. In accordance with the present invention, a series of "maps", or rotational speed control characteristics reflecting the factors mentioned above, are provided, and the pushbutton controls select among these characteristics, with the "take-off" power button permitting the highest maximum speeds, etc. In addition, automatic timing to reduce the maximum power levels, such as "Take-Off" power or "Performance Climb" power, is provided, to avoid over-stressing the turbine engines. The system may include additional arrangements for limiting the maximum allowable rotational speed of the turbine engine to a speed below that indicated by any of the "maps", when certain pushbuttons such as the "Approach" pushbutton is actuated.
Abstract:
The engine includes a main engine fuel flow, an augmentation fuel flow, and a variable area exhaust nozzle. Primary speed control means is powered by first electrical power supply means. Fan speed is controlled by modulation of main engine fuel flow. Loss of electrical power to the primary speed control means during augmented operation results in a reversion from fan speed control to core engine speed control while simultaneously reducing the augmentation fuel flow toward a minimum level and closing the variable area exhaust nozzle. Backup speed control means is coupled to the primary speed control means for limiting fan overspeed in augmented operation during loss of electrical power to the primary speed control means. The backup speed control means is powered by second electrical power supply means which is independent of the first power supply means. For example, in one embodiment involving aircraft application, the first electrical power supply means comprises an engine-driven alternator and the second electrical power supply means comprises an aircraft positioned power supply. The primary and backup speed control means may be coupled to separate windings of a single torque motor.
Abstract:
For a failure of a sensor utilized in the controls for a gas turbine engine, calculations from other parameters based on the thermodynamics of the cycle serve to simulate the value otherwise manifested by the failed sensor. In this instance, the ratio of burner pressure to engine inlet total pressure generated as a function of corrected rotor speed multiplied by a calculated engine total pressure from aircraft altitude and Mach No. simulates burner pressure utilized in the main fuel control for continuing automatic engine operation.
Abstract:
A turbine is stabilized in high speed, high altitude flight conditions by reducing the maximum augmenter fuel/air ratio in response to certain pressure and temperature conditions. Temperatures and pressures indicative of those at the combustor are sensed and the augmenter fuel schedule is accordingly modified to a level which provides reduced fuel/air ratios and stable burning conditions.
Abstract:
A control for a variable pitch fan propulsor driven by a turbine type of power plant which fan is mounted in an engine bypass duct having a variable exit nozzle. The control serves to coordinate the control of fuel flow to the engine, the area of the fan exit nozzle, and the pitch of the fan blades by biasing the power lever position signal with Flight Mach No. An additional feature is the inclusion of fan surge control derived from signals of flight Mach No. and corrected free turbine speed.
Abstract:
A fuel control apparatus for a gas turbine engine reheat system has a variable metering arrangement responsive to engine operating parameters to control fuel flow to the reheat burners, and a distributor valve arrangement between the metering arrangement and the burners. The distributor arrangement is operable in one mode to connect the metering arrangement to the burners, and in another mode to shut off fuel from the metering arrangement and to connect the burners to a low pressure drain.
Abstract:
Thrust of a turbine type of power plant is controlled by closing the loop on fuel flow as a function of the difference between the desired thrust and a precalculated inferred thrust signal in combination with an optimization system for obtaining optimum thrust specific fuel consumption.