Rolls-Royce Corporation

Rolls-Royce Controls and Data Services Limited

Alexander MacDonald

Arthur Laurence Rowe

Nigel Herbert Henson

Mohammad Khalid Khan

A fuel flow control system is configured to perform a method including: setting a fuel flow demand proportional to compressor discharge pressure; detecting an actual fuel flow; and applying an enhanced schedule for fuel flow demand while fuel flow demand is less than a predefined proportion of actual fuel flow.

Fuel flow control

A method () of controlling fuel flow in a gas turbine engine. First, detect a surge condition. Set fuel flow demand (W) proportional to compressor discharge pressure (P). Detect actual fuel flow (W). Then apply an enhanced schedule () for fuel flow demand (W) while fuel flow demand (W) is less than a predefined proportion (k) of actual fuel flow (W). Also a gas turbine engine (), fuel flow system () and fuel flow control system () each implementing the method ().

A method of detecting a shaft break in a turbine engine is provided. The shaft connects a torque-exerting turbine of the engine to a torque-receiving unit of the engine. The method includes: receiving repeated measurements of the rotational frequency of the torque-receiving unit and the rotational frequency measurements of the turbine; determining from the measurements an amount of shaft twist between the turbine and the torque-receiving unit; comparing the amount of twist with a threshold twist value; and signalling a shaft break when the amount of twist exceeds the threshold twist value and a pre-condition is met. The pre-condition includes determining from the measurements that the turbine rotational speed is greater than the simultaneous torque-receiving unit rotational speed by a threshold speed value.

Turbine engine shaft break detection

An engine fuel control system includes a metering valve to control fuel flow between the supply and delivery line with a pressure drop control regulating the pressure across the valve and maintain a substantially constant pressure across the valve. The fuel control system includes a backup system controllable by a pullback signal to operate the pressure control, thus increasing the pullback signal reducing the fuel flow between the supply and delivery line. The fuel control system detects a start of an engine overthrust event, and when the upward runaway is caused by the arrested overthrust event. The fuel control system's controller which (i) determines the overthrust detection, the pullback signal increase rate and the pullback signal offset, (ii) sends the pullback signal to the backup system at the rate of increase, and (iii), reduces the pullback signal to the backup system when the upward runaway is arrested by the offset.

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Derby, United Kingdom

Alexander MacDonald