Apparatus for synthesizing control parameters

Claim 2

Apparatus for synthesizing a control parameter for use in a gas turbine engine, comprising: first function generator means responsive to an engine operating parameter for generating a first signal simulating the value of a control parameter for the engine operating in a preselected base configuration; second function generator means responsive to an engine operating parameter for generating a second signal simulating the difference between the value of said control parameter for the base engine configuration and the value of said control parameter for a second preselected engine operating configuration different from said base configuration; means for operating on said second signal to produce a third signal simulating said difference in values for the actual engine operating configuration; and means for summing said first and third signals to produce a fourth signal simulating said control parameter for said actual engine operating configuration.

Claim 3

The apparatus according to claim 1 wherein said first, second, third and fourth signals are indicative of steady state engine operation, and said apparatus includes means for operating on said fourth signal to produce a control parameter which is corrected for transient engine operation.

Claim 4

The apparatus according to claim 1 wherein said first and second function generator means are responsive to the same engine operating parameter.

Claim 5

In a twin spool gas turbine engine having a low compressor and a high compressor, a control system for synthesizing the inlet temperature of the high compressor, comprising: means for determining the rotational speed of the low compressor and producing a signal indicative thereof; means for determining the inlet temperature to the low compressor and producing a signal indicative thereof; means responsive to said speed signal and said inlet temperature to produce a signal indicative of low compressor speed corrected for low compressor inlet temperature; first function generator responsive to said corrected low compressor speed signal for generating a first signal simulating the ratio of high compressor inlet temperature to low compressor inlet temperature for the engine operating at steady state in a preselected, base configuration; second function generator means responsive to said corrected low rotor speed signal for generating a second signal simulating the difference between said temperature ratio for said base configuration and said temperature ratio for the engine operating at steady state in a preselected second configuration different from said base configuration; means for operating on said second signal to produce a third signal simulating the difference between said base configuration temperature ratio and said second configuration temperature ratio for the engine operating at steady state in its actual engine configuration; means for summing said first and third signals to produce a fourth signal simulating said temperature ratio for the engine operating at steady state in said actual engine configuration; and means for multiplying said temperature ratio represented by said fourth signal by said low compressor inlet temperature to generate a fifth signal simulating the actual inlet temperature to the high compressor under steady state conditions.

Claim 6

In a twin spool gas turbine engine having a low compressor and a high compressor, a control system for synthesizing the inlet temperature of the high compressor, comprising: means for determining the rotational speed of the low compressor and producing a signal indicative thereof; means for determining the inlet temperature to the low compressor and producing a signal indicative thereof; means responsive to said speed signal and said inlet temperature to produce a signal indicative of low compressor speed corrected for low compressor inlet temperature; first function generator responsive to said corrected low compressor speed signal for generating a first signal simulating the ratio of high compressor inlet temperature to low compressor inlet temperature for the engine operating at steady state in a preselected, base configuration; second function generator means responsive to said corrected low rotor speed signal for generating a second signal simulating the difference between said temperature ratio for said base configuration and said temperature ratio for the engine operating at steady state in a preselected second configuration different from said base configuration; means for operating on said second signal to produce a third signal simulating the difference between said base configuration temperature ratio and said second configuration temperature ratio for the engine operating at steady state in its actual engine configuration; means for summing said first and third signals to produce a fourth signal simulating said temperature ratio for the engine operating at steady state in said actual engine configuration; and means for multiplying said temperature ratio represented by said fourth signal by said low compressor inlet temperature to generate a fifth signal simulating the actual inlet temperature to the high compressor under steady state conditions.

Claim 7

The control system according to claim 4 including third function generator means responsive to said fifth signal for generating a sixth signal indicative of simulated high compressor inlet temperature corrected for transient engine operation.

Claim 8

The control system according to claim 5, wherein the engine includes a stage of variable geometry stator vanes in said high compressor, the apparatus further comprising: means for determining the speed of said high compressor and producing a signal indicative thereof; means responsive to said high compressor speed signal and said simulated high compressor inlet temperature corrected for transient engine operation for producing a signal simulating the high compressor speed corrected for high compressor inlet temperature; and fourth function generator means responsive to said simulated, corrected high compressor speed signal for generating a position signal indicative of the desired position of said stator vanes; and actuation means connected to said stator vanes and responsive to said position signal for moving said stator vanes to the desired position.

Claim 9

The control system according to claim 6 wherein the engine includes variable position bleed valve means for bleeeding air from one of said compressors, and said base engine configuration is a configuration with said valve means in a first position permitting a first amount of bleed, and said second engine configuration is a configuration with said valve means in a second position different from said first position permitting a second amount of bleed.