Abstract: A system for actively controlling the working line location within a low pressure compressor. The system includes a plurality of variable inlet guide vanes that are adjusted to maintain the working line at a constant level as the low pressure compressor rotates at a constant speed.

Abstract: It is known that power is normally extracted within a gas turbine engine from a shaft in order to drive auxiliary devices such as electrical power generators. With high extraction rates from such shafts there is mismatching in rotational speeds between the shafts which must be adjusted through leakage taken from valves 8, 9. By measuring parameters and in particular pressure at a number of positions or parts within an engine arrangement 1 and comparing those parameters either through ratios or directly with reference values a controller can be configured in order to choose the correct sequence and scheduling of the valves 8, 9 opening to balance shaft speed. In such circumstances more efficient operation of the engine arrangement can be achieved over a wider range of engine speeds including idling.

Abstract: It is known that overshoot in fuel flow rate as a result of compensating for engine heat soak effects can create transient over values in desired thrust parameters. These over values may be displayed and/or utilised in other engine control systems, and although transient may create problems within the engine and apprehension with a user. By adjusting the normally calculated fuel flow rate to a fuel regulator by the introduction of a fuel flow adjustment dependent upon a variable which is related to heat soak effects it is possible to reduce the extent of overshoot as well as the transient time period of that overshoot to ongoing operational state. The variable used may be direct or indirect and will generally utilise a temperature sensor within the engine and/or other engine control procedures which may be extrapolated from such sensor values to provide a variable for heat soak compensation.

Abstract: A method for operating a multi-stage combustor of a gas turbine engine comprises: (a) determining a combustor air entry temperature; (b) determining the combustor air entry flow rate; and (c) controlling the fuel split ratio to stages of the combustor on the basis of the combustor air entry flow rate and the combustor air entry temperature.

Abstract: A stall detection and recovery system (10) for a gas turbine engine (1) comprises surge detection means (50 for detecting an engine surge and providing a surge detection signal (154) for indicating said engine surge. The system also includes stall detection means to provide a stall detection signal (48) relating to a condition of gas flowing through the engine (1). The system (10) also includes stall recovery means (58) to receive the surge detection signal (154) and the stall detection signal. The stall recovery means (58) is arranged to control combustor operating means, whereby when the stall detection signal (48) indicates an engine stall, the stall recovery means controls the combustor operating means to effect recover from the stall.

Abstract: A system for actively controlling the working line location within a low pressure compressor. The system includes a plurality of variable inlet guide vanes that are adjusted to maintain the working line at a constant level as the low pressure compressor rotates at a constant speed.