Stress limiter apparatus for a gas turbine engine
First Claim
1. A fuel control for gas turbine comprising:
- (a) means for controlling the fuel flow to the gas turbine engine as a function of a demanded speed signal;
(b) means for generating said demanded speed signal as the time integral of a selected acceleration term;
(c) means for generating a demanded acceleration term as a function of at least one operating parameter of the engine;
(d) a plurality of summing means for generating difference signals between an actual parameter signal related to a stress limit and a predetermined limit value;
(e) a plurality of scheduling means for determining stress limit acceleration terms as functions of the difference signals generated by said summing means; and
(f) means for comparing said acceleration terms and for generating said elected acceleration term as the lowest of said acceleration terms, wherein said scheduling means provides;
(i) a difference signal determined as a function having a maximum acceleration value exceeding the maximum value of said demanded acceleration for operation of the engine in a normal range, (ii) decreasing acceleration values for operation of the engine within a predetermined range of a stress limit, (iii) a zero acceleration value for operation of the engine at the stress limit, (iv) increasing deceleration values for operation of the engine beyond the stress limit, and (v) a maximum deceleration value for operation of the engine in a dangerous range.
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Abstract
A stress limiter apparatus for a gas turbine engine (10) is disclosed. A proportional fuel fuel control (11) regulates the fuel flow (Wf) from a hydromechanical unit (36) based upon an error signal (E) representing the difference between a demanded speed signal (Nd) and an actual speed signal (N1). The demanded speed signal (Nd) is generated by an integrator (32) as the time integral of one of the acceleration terms (A1, A2, A3) selected by gate 38. The demanded acceleration term (A1) is generated by junction (26) as the difference between the demanded signal (Nd) and a scheduled speed signal (Ngs). The acceleration terms (A2, A3) are generated by junctions (44, 46) and scheduling means (40, 42) which form stress limiter circuits.
34 Citations
21 Claims
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1. A fuel control for gas turbine comprising:
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(a) means for controlling the fuel flow to the gas turbine engine as a function of a demanded speed signal; (b) means for generating said demanded speed signal as the time integral of a selected acceleration term; (c) means for generating a demanded acceleration term as a function of at least one operating parameter of the engine; (d) a plurality of summing means for generating difference signals between an actual parameter signal related to a stress limit and a predetermined limit value; (e) a plurality of scheduling means for determining stress limit acceleration terms as functions of the difference signals generated by said summing means; and (f) means for comparing said acceleration terms and for generating said elected acceleration term as the lowest of said acceleration terms, wherein said scheduling means provides; (i) a difference signal determined as a function having a maximum acceleration value exceeding the maximum value of said demanded acceleration for operation of the engine in a normal range, (ii) decreasing acceleration values for operation of the engine within a predetermined range of a stress limit, (iii) a zero acceleration value for operation of the engine at the stress limit, (iv) increasing deceleration values for operation of the engine beyond the stress limit, and (v) a maximum deceleration value for operation of the engine in a dangerous range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification