US3713290A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas turbine engine fuel control
Assignee: National Aeronautics and Space Administration
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Filing: 1971-05-28
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Granted: 1973-01-30
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Expires: 1991-05-28
Abstract
Abstract A variable orifice system that is responsive to compressor inlet pressure and temperature, compressor discharge pressure and rotational speed of a gas-turbine engine is incorporated into a hydraulic circuit that includes a zero gradient pump driven at a speed proportional to the speed of the engine. The resulting system provides control of fuel rate for starting, steady running, acceleration and deceleration under varying altitudes and flight speeds.
Inventors
- 👤 H Gold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:42
CPC Classifications
F; F02; F02C; F02C9/00; F02C9/26; F02C9/28; F02C9/32
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
298 words
A fuel control for a gas-turbine engine comprising a liquid fuel supply means, means for pressurizing the liquid, a positive displacement pump operating at a speed proportional to the speed of the engine, pressure responsive means operating in conjunction with said pressurizing means to maintain the pressure gradient across said pump at zero, a conduit for receiving the flow from said pump, flow restriction means in said conduit, a branch conduit for divertIng flow from the upstream side of said pump, second flow restriction means in said branch conduit, said conduits being joined downstream of said first mentioned flow restrictions means, whereby the pressure difference across said second flow restriction means is made equal to the pressure difference across said first mentioned flow restriction means and said flows are combined, a third conduit for delivering said combined flow to the engine; the second mentioned flow restriction means being a network of variable orifices, said network comprising: a first variable orifice and a second variable orifice responsive to the difference between compressor discharge pressure and compressor inlet pressure, a third variable orifice responsive to engine speed and a fourth variable orifice responsive to compressor inlet absolute pressure; said first variable orifice and said fourth variable orifice forming a parallel array, said parallel array and said third variable orifice forming a series pair, said series pair and said second variable orifice forming a second parallel array; said third variable orifice being operable to regulate the rate of fuel delivery to the engine during steady running, the first mentioned parallel array and said second variable orifice being operable to limit the maximum rate of fuel delivery during engine acceleration and said second variable orifice being operable to limit the minimum rate of delivery of fuel to the engine during engine deceleration.
Claim 2
Dependent Claim
298 words
A fuel control for a gas-turbine engine comprising a liquid fuel supply means, means for pressurizing the liquid, a positive displacement pump operating at a speed proportional to the speed of the engine, pressure responsive means operating in conjunction with said pressurizing means to maintain the pressure gradient across said pump at zero, a conduit for receiving the flow from said pump, flow restriction means in said conduit, a branch conduit for divertIng flow from the upstream side of said pump, second flow restriction means in said branch conduit, said conduits being joined downstream of said first mentioned flow restrictions means, whereby the pressure difference across said second flow restriction means is made equal to the pressure difference across said first mentioned flow restriction means and said flows are combined, a third conduit for delivering said combined flow to the engine; the second mentioned flow restriction means being a network of variable orifices, said network comprising: a first variable orifice and a second variable orifice responsive to the difference between compressor discharge pressure and compressor inlet pressure, a third variable orifice responsive to engine speed and a fourth variable orifice responsive to compressor inlet absolute pressure; said first variable orifice and said fourth variable orifice forming a parallel array, said parallel array and said third variable orifice forming a series pair, said series pair and said second variable orifice forming a second parallel array; said third variable orifice being operable to regulate the rate of fuel delivery to the engine during steady running, the first mentioned parallel array and said second variable orifice being operable to limit the maximum rate of fuel delivery during engine acceleration and said second variable orifice being operable to limit the minimum rate of delivery of fuel to the engine during engine deceleration.
Claim 3
Dependent Claim
298 words
A fuel control for a gas-turbine engine comprising a liquid fuel supply means, means for pressurizing the liquid, a positive displacement pump operating at a speed proportional to the speed of the engine, pressure responsive means operating in conjunction with said pressurizing means to maintain the pressure gradient across said pump at zero, a conduit for receiving the flow from said pump, flow restriction means in said conduit, a branch conduit for divertIng flow from the upstream side of said pump, second flow restriction means in said branch conduit, said conduits being joined downstream of said first mentioned flow restrictions means, whereby the pressure difference across said second flow restriction means is made equal to the pressure difference across said first mentioned flow restriction means and said flows are combined, a third conduit for delivering said combined flow to the engine; the second mentioned flow restriction means being a network of variable orifices, said network comprising: a first variable orifice and a second variable orifice responsive to the difference between compressor discharge pressure and compressor inlet pressure, a third variable orifice responsive to engine speed and a fourth variable orifice responsive to compressor inlet absolute pressure; said first variable orifice and said fourth variable orifice forming a parallel array, said parallel array and said third variable orifice forming a series pair, said series pair and said second variable orifice forming a second parallel array; said third variable orifice being operable to regulate the rate of fuel delivery to the engine during steady running, the first mentioned parallel array and said second variable orifice being operable to limit the maximum rate of fuel delivery during engine acceleration and said second variable orifice being operable to limit the minimum rate of delivery of fuel to the engine during engine deceleration.
Claim 4
Dependent Claim
298 words
A fuel control for a gas-turbine engine comprising a liquid fuel supply means, means for pressurizing the liquid, a positive displacement pump operating at a speed proportional to the speed of the engine, pressure responsive means operating in conjunction with said pressurizing means to maintain the pressure gradient across said pump at zero, a conduit for receiving the flow from said pump, flow restriction means in said conduit, a branch conduit for divertIng flow from the upstream side of said pump, second flow restriction means in said branch conduit, said conduits being joined downstream of said first mentioned flow restrictions means, whereby the pressure difference across said second flow restriction means is made equal to the pressure difference across said first mentioned flow restriction means and said flows are combined, a third conduit for delivering said combined flow to the engine; the second mentioned flow restriction means being a network of variable orifices, said network comprising: a first variable orifice and a second variable orifice responsive to the difference between compressor discharge pressure and compressor inlet pressure, a third variable orifice responsive to engine speed and a fourth variable orifice responsive to compressor inlet absolute pressure; said first variable orifice and said fourth variable orifice forming a parallel array, said parallel array and said third variable orifice forming a series pair, said series pair and said second variable orifice forming a second parallel array; said third variable orifice being operable to regulate the rate of fuel delivery to the engine during steady running, the first mentioned parallel array and said second variable orifice being operable to limit the maximum rate of fuel delivery during engine acceleration and said second variable orifice being operable to limit the minimum rate of delivery of fuel to the engine during engine deceleration.
Claim 5
Dependent Claim
73 words
In the system of claim 1, said first mentioned flow restriction means being a spring biased, pressure responsive variable orifice, said variable orifice being responsive to said spring bias and the pressure difference across said variable orifice, said variable orifice being thereby responsive to the rate of flow from said pump, and being so disposed to open gradually from cranking speed to idle speed and to remain at fixed opening above idle speed.
Claim 6
Dependent Claim
75 words
In the orifice network of claim 1, a fifth variable orifice responsive to compressor inlet absolute pressure and a sixth variable orifice responsive to compressor inlet temperature, said fifth and said sixth variable orifice forming a second series pair, said second series pair and said fourth variable orifice forming a parallel array, said sixth variable orifice being operable above a specified temperature to reduce the limit of maximum rate of fuel delivery during engine acceleration.
Claim 7
Dependent Claim
23 words
In the orifice network of claim 1, said fourth variable orifice being responsive to compressor absolute inlet pressure and to compressor inlet temperature.
Claim 8
Dependent Claim
144 words
In claim 4, said fourth variable orifice comprising an orifice structure, said structure comprising a cylindrical sleeve and a mating cylindrical piston, said piston having an axial bore, a slot being through the wall of said piston and opening into said bore, a second slot being through the wall of said sleeve, said piston being coupled to a linear actuator, said linear actuator being responsive to compressor inlet pressure, said sleeve being coupled to a rotary actuator, said rotary actuator being responsive to compressor inlet temperature, said slots being overlapped to form said variable orifice, the area of said orifice being variable through the axial displacement of said piston and/or the rotary displacement of said sleeve, the interior of said piston being in communication with a point between said first and third orifices and said second slot being in communication with said third conduit.
Claim 9
Dependent Claim
65 words
In the orifice network of claim 1, said third variable orifice comprising an orifice structure, said structure being actuated by a pressure responsive, spring biased movable wall, said wall being between a first and a second pressure chamber, said first chamber being in communication with the pressure upstream of said network, said second chamber being in communication with the pressure downstream of said orifice network.
Claim 10
Dependent Claim
39 words
In the orifice network of claim 1, said third variable orifice comprising an orifice struCture, said structure being actuated by a spring biased fly-weight mechanism, said mechanism being driven at a speed proportional to the speed of said engine.
Claim 11
Dependent Claim
13 words
In claim 1, said positive displacement pump being of the adjustable displacement type.
Claim 12
Dependent Claim
202 words
In the orifice network of claim 1, said first and said second variable orifices comprising a multi-orifice structure, said structure comprising a cylindrical valve spool and a mating valve sleeve, a pair of separate chambers in said spool, each chamber being provided with an inlet opening and an outlet opening in the wall of said spool, an inlet annulus in said sleeve at each inlet opening, an outlet annulus in said sleeve at each outlet opening, said outlet annuluses communicating with said third conduit, said inlet annulus of one chamber communicating with the upstream side of said third orifice, said inlet annulus of the other chamber communicating with the downstream side of said third orifice, said outlet annuluses being axially positioned such that axial movement of said spool varies the area of each outlet exposed to respective outlet annuluses to provide variable orifices, a coaxial cylindrical piston coupled to said spool, said spool and said piston defining a spool assembly, a pair of opposing springs axially restraining said spool assembly and passage means communicating compressor inlet pressure to the piston end of said spool assembly and compressor discharge pressure to the opposite side of said piston and opposite end of said spool.
Claim 13
Dependent Claim
199 words
In a gas-turbine engine fuel control system of the type utilizing a zero-gradient pump and a flow control means connected serially between a fuel supply pump and a conduit which delivers fuel to a fuel injection system, the improvement comprising; a second flow control means connected between the output of said fuel supply pump and said conduit, said second flow control means comprising first and second variable orifices connected serially between the output of said fuel supply pump and said conduit, a third variable orifice connected in parallel with said second orifice, fourth and fifth variable orifices connected in series relationship to each other and in parallel with said third orifice, a sixth variable orifice connected between the output of said fuel supply pump and said conduit, means for varying the area of said first variable orifice in proportion to engine speed, means for varying the area of said third and fifth variable orifices in accordance with compressor inlet pressure, means for varying the area of said fourth variable orifice inversely with inlet temperature, and, means for varying the area of said second and sixth variable orifices in accordance with compressor discharge pressure and inversely to compressor inlet pressure.
Claim 14
Dependent Claim
199 words
In a gas-turbine engine fuel control system of the type utilizing a zero-gradient pump and a flow control means connected serially between a fuel supply pump and a conduit which delivers fuel to a fuel injection system, the improvement comprising; a second flow control means connected between the output of said fuel supply pump and said conduit, said second flow control means comprising first and second variable orifices connected serially between the output of said fuel supply pump and said conduit, a third variable orifice connected in parallel with said second orifice, fourth and fifth variable orifices connected in series relationship to each other and in parallel with said third orifice, a sixth variable orifice connected between the output of said fuel supply pump and said conduit, means for varying the area of said first variable orifice in proportion to engine speed, means for varying the area of said third and fifth variable orifices in accordance with compressor inlet pressure, means for varying the area of said fourth variable orifice inversely with inlet temperature, and, means for varying the area of said second and sixth variable orifices in accordance with compressor discharge pressure and inversely to compressor inlet pressure.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-30 | 1976-07-31 | 1977-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-30 | 1980-07-31 | 1981-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-30 | 1984-07-31 | 1985-01-30 | $7700.00 | Window Closed / Lapsed |