Control system for gas turbine engines

Claim 2

Control system for gas turbines, comprising a gas generator operatively associated with a variable geometry unit with the working line of the gas generator geing adjusted to each related speed by variation of the geometry through the control system, characterized in that means is provided utilizing the control function q1 . po1 f (To1).po3 k for positioning the gas generator working line and for at least one of acceleration and fuel supply, wherein q1 is the ram pressure, po1 is the total pressure, To1 is the absolute temperature upstream of the compressor, po3 is the total pressure measured between the compressor and turbine, and Alpha and k are constant values, the positioning means including a control circuit for the variable geometry as well as a control circuit for the gas generator speed, the variable geometry control circuit comprising measuring points for the measuring values of the total pressure upstream of the compressor (po1) and ram pressure upstream of the compressor (q1), first multiplying means for converting the measured values into a first signal proportional to the fUnction utilized for positioning the working line and a function generator, regulator means for converting the measured value po3 to a value po3 , second multiplier means for converting the values po3 and f (To1) which is a function of the measured value To1 into a second signal according to the control function so that the first signal is compared with the second signal, and the differential signal generated in the function generator constitutes a control impulse for enabling adjustment of the geometry. geomerry.

Claim 3

Control system according to claim 1, wherein the variable geometry unit includes variable guide vanes upstream of a free-power turbine of a two-shaft engine having a heat exchanger, wherein the heat of the combustion gases is transferred to the air compressed in the gas generator.

Claim 4

Control system according to claim 1, wherein the gas turbine is a turbojet engine and the variable geometry unit includes a variable geometry thrust nozzle in the turbojet engine.

Claim 5

Control system according to claim 1, wherein the function f(To1) is equal to a constant value below a temperature To1.

Claim 6

Control system according to claim 1, wherein the positioning means utilizing the control function comprises at least one of mechanical, electronic hydraulic, pneumatic components and combinations thereof.

Claim 7

Control system according to claim 1, wherein the first multiplying means comprises a first pressure chamber subjected to total pressure (po1) containing a plurality of bellows operatively communicated with each other and subjected to static pressure (p1), a first slide having an opening and being operatively connected with the bellows by a first connecting rod, and a second pressure chamber subjected to total pressure (po1) containing a plurality of evacuated bellows operatively communicated with each other, a second slide having an opening and being operatively connected with the evacuated bellows by a second connecting rod, the second slide contacting the first slide and the second connecting rod being arranged normal to the first connecting rod, the openings in the first and second slides providing a flow cross-sectional area (F1) which is proportional to the product of po1 and qi.

Claim 8

Control system according to claim 1, wherein the second multiplying means comprises a first pressure chamber subjected to pressure (po3) and a second pressure chamber subjected to pressure corresponding to intake temperature (To1), both pressure chambers containing a plurality of aligned evacuated bellows which are operatively connected to each other by a connecting rod and which are connected to a slide with an opening corresponding to an exponential function by means of a second connecting rod, and the slide being movable on a face member having an opening, the openings of the slide and face member providing a flow cross-sectional area (F2).

Claim 9

Control system according to claim 7, wherein the first multiplying means comprises a first pressure chamber subjected to total pressure (po1) containing a plurality of bellows operatively communicated with each other and subjected to static pressure (p1), a first slide having an opening and being operatively connected with the bellows by a first connecting rod, and a second pressure chamber subjected to total pressure (po1) containing a plurality of evacuated bellows operatively communicated with each other, a second slide having an opening and being operatively connected with the evacuated bellows by a second connecting rod, the second slide contacting the first slide and the second connecting rod being arranged normal to the first connecting rod, the openings in the first and second slides providing a flow cross-sectional area (F1).

Claim 10

Control system according to claim 1, wherein the gas generator speEd control circuit compares the speed signal of the gas generator with the value selected by a power control lever and includes speed governor means influencing fuel flow which, in certain speed ranges, is also influenced by the speed of a free-power turbine.

Claim 11

Control system according to claim 9, wherein the function f(To1) is equal to a constant value below a temperature To1.

Claim 12

Control system according to claim 10, wherein a linear temperature function f(To1) K2 (Too + (To1 - Too)) based on an ambient temperature Too is selected, and K2 represents a constant and To1 the intake temperature.

Claim 13

Control system according to claim 1, wherein speed governor means is provided for setting the gas generator speed which controls the supply of fuel to the combustion chamber.

Claim 14

Control system according to claim 12, wherein the speed governor means is a flyweight-governor with springs counteracting the centrifugal force being preloaded by a power control lever.

Claim 15

Control system according to claim 1, wherein fuel supply limiting means is provided for adjusting the control function.

Claim 16

Control system according to claim 14, wherein the fuel supply limiting means is an acceleration governor.

Claim 17

Control system according to claim 2, wherein speed governor means is provided for limiting the speed of the free-power turbine by controlling the gas generator speed.

Claim 18

Control system according to claim 2, wherein signal transmitter means is provided for indicating an upper and a lower limit for the gas generator and free-power turbine speed related to each other.

Claim 19

Control system according to claim 1, wherein means is provided for opening of the variable geometry both during starting and also at least up to idling speed.

Claim 20

Control system according to claim 1, wherein means is provided for generating a signal for adjustment of the variable geometry during transient operating conditions and power variations due to a difference between products appearing in the control function.

Claim 21

Control system according to claim 19, wherein the variable geometry unit includes variable guide vanes upstream of a free-power turbine of a two-shaft engine having a heat exchanger, wherein the heat of the combustion gases is transferred to the air compressed in the gas generator.

Claim 22

Control system according to claim 20, wherein means are provided for the overspeed protection both for the gas generator and the free-power turbine.

Claim 23

Control system according to claim 6, wherein the second pressure chamber is adjustable as a function of temperature (To3so o3) a maximum permissible temperature in the gas generator and turbine inlet or outlet can be maintained according to the control function by automatic adjustment.

Claim 24

Control system according to claim 8, wherein the second pressure chamber is adjustable as a function of temperature (To3) so that a maximum permissible temperature in the gas generator and turbine inlet or outlet can be maintained according to the control function by automatic adjustment.

Claim 25

Control system according to claim 23, wherein the function generator compares the two signals and comprises two comparative measuring tubes, and the comparative measuring tubes include orifices, with the prevailing pressure being sensed downstream of the flow cross-sectional areas (F1 and F2) at measuring points.

Claim 26

Control system according to claim 24, wherein the correcting condition of greater magnitude of the control impulse as sensed on the comparative measuring tube serves for adjusting the variable geometry.

Claim 27

Control system according to claim 25, wherein the variable geometry unit includes variable guide vanes upstream of a free-power turbine of a two-shaft engine having a heat exchanger, wherein the heat of the combustion gases is transferred to thE air compressed in the gas generator.

Claim 28

Control system according to claim 25, wherein a comparison bridge connection means is provided for comparing the two functions of the control function.

Claim 29

Control system according to claim 26, wherein with the correcting conditions used as a control impulse, the control impulse serves for adjusting control piston means arranged in a cylinder connected to an actuating cylinder containing actuating piston means for the guide vane variation via lines which are alternatively closed by control edges.

Claim 30

Control system according to claim 28, wherein a comparison bridge connection means is provided for comparing the two functions of the control function.

Claim 31

Control system according to claim 26, wherein a control cylinder having control piston means disposed therein is operatively arranged between the pressures sensed at the measuring points in the comparative measuring tubes and directs fuel from a speed governor across control edges both to the combustion chamber and to another cylinder, and a spring-loaded actuating piston means arranged in said another cylinder is provided for operating a valve located in a pressure line between one measuring point and an actuating cylinder.

Claim 32

Control system according to claim 30, wherein the valve closes the pressure line during acceleration so that the guide vanes remain in open position.

Claim 33

Control system according to claim 28, wherein a valve for the actuation of the guide vanes is arranged upstream of the actuating cylinder which opens a line, when a brake lever means is operated, to allow pivoting of the guide vanes into an opposite direction.

Claim 34

Control system for gas turbines, comprising a gas generator operatively associated with a variable geometry unit with the working line of the gas generator being adjusted to each related speed by variation of the geometry through the control system, characterized in that means is provided utilizing the control function q1 . (x.po1 +y.po1 + . . . +zn.po1 ) f(To1). (a.po3 +b.po3 + . . . +z.po3 )k, for positioning the gas generator working line and for at least one of acceleration and fuel supply, wherein q1 is the ram pressure, po1 is the total pressure, To1 is the absolute pressure upstream of the compressor, po3 is the total pressure measured between the compressor and the turbine, wherein x, y, zn, k, a, b, z, Alpha Beta , and delta are constants, the positioning means including a control circuit for the variable geometry as well as a control circuit for the gas generator speed, the variable geometry control circuit comprising measuring points for the measuring values of the total pressure upstream of the compressor (po1) and ram pressure upstream of the compressor (q1), first multiplying means for converting the measured values into a first signal proportional to the function utilized for positioning the working line and a function generator, measuring points for the measuring values of po3 and To1, means for converting the measured values po3 and To1 to values (a.po3 +b.po3 + . . . +z.po3 ) and f (To1), second multiplier means for converting the values (a.po3+b.po3+ . . . +z.po3 ) and f(To1) into a second signal according to the control function so that the first signal is compared with the second signal, and the differential signal generated in the function generator constitutes a control impulse for enabling adjustment of the variable geometry.

Claim 35

Control system for gas turbines, comprising a gas generator operatively associated with a variable geometry unit with the working line of the gas generator being adjusted to each related speed by variation of the geometry through the control system, characterized in that means is provided utilizing the control function q1 . (x.po1 +y.po1 + . . . +zn.po1 ) f(To1). (a.po3 +b.po3 + . . . +z.po3 )k, for positioning the gas generator working line and for at least one of acceleration and fuel supply, wherein q1 is the ram pressure, po1 is the total pressure, To1 is the absolute pressure upstream of the compressor, po3 is the total pressure measured between the compressor and the turbine, wherein x, y, zn, k, a, b, z, Alpha Beta , and delta are constants, the positioning means including a control circuit for the variable geometry as well as a control circuit for the gas generator speed, the variable geometry control circuit comprising measuring points for the measuring values of the total pressure upstream of the compressor (po1) and ram pressure upstream of the compressor (q1), first multiplying means for converting the measured values into a first signal proportional to the function utilized for positioning the working line and a function generator, measuring points for the measuring values of po3 and To1, means for converting the measured values po3 and To1 to values (a.po3 +b.po3 + . . . +z.po3 ) and f (To1), second multiplier means for converting the values (a.po3+b.po3+ . . . +z.po3 ) and f(To1) into a second signal according to the control function so that the first signal is compared with the second signal, and the differential signal generated in the function generator constitutes a control impulse for enabling adjustment of the variable geometry.

Claim 36

Control system according to claim 33, wherein a linear temperature function f (To1) K2 ( Too + (To1 - Too)) based on an ambient temperature Too is selected, and K2 represents a constant and To1 the intake temperature.

Claim 37

Control system according to claim 34, wherein the function f(To1) is equal to a constant value below a temperature To1.