Abstract: An engine start control circuit and fuel system for a gas turbine engine with a burner having a prevaporization chamber has metered fuel flow through a pilot and main fuel flow system in which a pilot nozzle of the air assist type is used to ignite fuel from a main fuel manifold that is supplied to the prevaporization chamber as a wall film of fuel. Control means are provided to energize the pilot fuel system to light the main fuel when the burner inlet temperature is below a predetermined set temperature corresponding to a temperature at which good fuel vaporization will occur on the walls of the prevaporization chamber. The control means also includes means operative in response to higher burner inlet temperatures to produce start and ignition of the main fuel manifold into the prechamber.

Abstract: A single-shaft gas turbine engine suited for road vehicle propulsion has variable inlet and outlet guide vanes in the compressor of the engine and a variable turbine nozzle. These variable features are called engine variable goemetry (EVG). In normal operation, the areas of the flow paths at the inlet and outlet of the compressor and of the turbine nozzle are varied with desired power level to suit varying air flow through the engine. An actuator increases the areas in response to a request for increased power output.In a braking mode, the compressor variable geometry is decoupled from the actuator and remains at a minimum flow condition while the turbine nozzle is opened as the power request decreases below a particular low value. The opening of the turbine nozzle decreases the engine power output, thus increasing its capacity to absorb power from the vehicle. Logic circuits control the coupling and decoupling of the compressor variable geometry.

Abstract: A fuel and burner variable geometry (BVG) control for a gas turbine engine. Fuel is controlled in response to the product of desired overall fuel-air ratio and a value of air flow derived from gas generator turbine speed. The desired fuel-air ratio is controlled by a speed governor, and by acceleration and deceleration limits varied as a function of measured burner inlet temperature. A compensated turbine inlet temperature (TIT) signal is derived from measurement of actual turbine inlet temperature and acceleration or deceleration compensation based upon rate of change of the desired fuel-air ratio. The difference between the compensated TIT and the burner inlet temperature (BIT) is the burner temperature rise.The setting of air flow control devices in the combustion apparatus (BVG) determines the ratio of primary to total air. The desired ratio to control BVG is computed by dividing burner temperature rise by flame temperature rise.