Williams International Co., L.l.c.

Ray D Lickfold

Gregg G Williams

Robert S Thompson, Jr

A control schedule incorporating a relationship between corrected torque and inlet pressure is selected or determined responsive to a power-level command representative of a level of power to be transmitted to a controllable load by a single-spool turboshaft engine. At least a substantial portion of the control schedule provides for a flat-rated power level by the single-spool turboshaft engine substantially independent of associated inlet air pressure and inlet air temperature, and for at least one selectable mode of operation, the control schedule provides for minimizing or nearly minimizing a measure of fuel consumption, and for at least one other selectable mode of operation, the control schedule provides for operation at a substantially fixed level of rotational speed.

System and method for controlling a single-spool turboshaft engine

One of a controllable load and a fuel flow to a single-spool turboshaft engine is controlled so that a rotational speed of a single-spool turboshaft engine is substantially regulated to a level corresponding to a corrected rotational speed command, and the other of the fuel flow and the controllable load is controlled so that a torque transmitted from the single-spool turboshaft engine to the controllable load is substantially regulated to a level corresponding to a corrected torque command. Under at least one operating condition, the corrected rotational speed command is determined so as to minimize or nearly minimize a measure of fuel consumption by the single-spool turboshaft engine when operated so that the torque transmitted to the controllable load corresponds to the corrected torque command.

A controller receives a power-level command representative of a level of power to be transmitted by a single-spool turboshaft engine to a controllable load. A torque command determined responsive to a measure of inlet pressure, from a control schedule responsive to the power-level command, is representative of a level of torque to be transmitted by an element to drive the controllable load. Under some operating conditions, a rotational speed command provides for at least nearly minimizing a measure of associated fuel consumption when the transmitted torque is regulated to the level corresponding to the torque command by controlling one of the controllable load and a fuel flow to the engine, and the other of the controllable load and the fuel flow to the engine is controlled so as to regulate an associated rotational speed to a level corresponding to the rotational speed command.

A load applied to a low pressure spool of a two-spool turboshaft engine is controlled responsive to inlet pressure and temperature so as to regulate a relationship between the rotational speeds of the low and high pressure spools of the two-spool turboshaft engine so as to provide for operating the low pressure compressor attached to the low pressure spool with sufficient surge margin.

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Brighton, MI, United States of America

Ray D Lickfold