JP2797719B2 - Fuel flow control device for gas turbine engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel flow control device for a gas turbine engine.

[0002]

2. Description of the Related Art FIG. 3 shows a general fuel flow rate control device for a gas turbine engine when a constant displacement pump 1 is used. The gas is supplied to the combustion chamber of the gas turbine engine 42 through the supply passage 33, and the constant displacement pump 1 is driven by directly taking out the rotation shaft output of the gas turbine engine 42 by a gear mechanism or the like. It is.

In the fuel flow control device for a gas turbine engine, a circulation flow path 24 connecting the discharge side and the suction side of the constant displacement pump 1 is formed. At the required position, the nozzle 6 and the nozzle 6
A proportional solenoid valve 7 having a flapper 8 capable of opening and closing
A throttle 5 is provided upstream of the proportional solenoid valve 7 in the circulation flow path 24.

A measuring piston 2 having, at both ends, a small-diameter piston portion 2a slidably fitted into a small-diameter cylinder portion 25 and a large-diameter piston portion 2b slidably fitted into a large-diameter cylinder portion 26 is provided. Adjusting screw 3 for restricting movement of the large-diameter piston portion 2b of the measuring piston 2 toward the head-side chamber 27;
And a constant displacement pump 1 upstream of the throttle 5 of the circulation channel 24 and the head side chamber 28 of the small diameter cylinder 25.
A balance flow path 29 for communicating with the discharge side and a balance flow path 30 for communicating the head side chamber 27 of the large-diameter cylinder section 26 with the position between the throttle 5 and the proportional solenoid valve 7 of the circulation flow path 24. And a connecting flow path 32 for connecting the rod-side chamber 31 of the large-diameter cylinder section 26 with the suction side of the constant-volume pump 1 of the circulation flow path 24.
Is formed.

In the middle of the supply channel 33, there is formed a measuring section 4 whose opening is adjusted in accordance with the movement of the measuring piston 2, and the circulation channel is provided from the upstream side of the measuring section 4 of the supply channel 33. 24 constant displacement pump 1 regulating flow path 3 leading to suction side
A differential pressure control device 35 for keeping the upstream and downstream differential pressure (P1-P2) of the measuring section 4 of the supply flow path 33 constant is provided in the adjustment flow path 34 in the middle of the adjustment flow path 34.

The differential pressure control device 35 includes a diaphragm 1
0, the casing 38 is divided into an upstream chamber 36 communicating with the adjustment channel 34 and a downstream chamber 37 communicating downstream of the measuring section 4 of the supply channel 33, and the inside of the upstream chamber 36 of the casing 38 A nozzle 9 arranged to face the diaphragm 10; and a diaphragm 10 in the downstream chamber 37 of the casing 38
The opening of the nozzle 9 is adjusted by the diaphragm 10 in accordance with changes in the upstream and downstream pressures P1, P2 of the measuring section 4 in the supply flow path 33, and the differential pressure (P1- P2) is kept constant, and fuel proportional to the opening area of the metering section 4 of the metering piston 2 is supplied to the combustion chamber of the gas turbine engine 42.

Further, a predetermined position of the supply flow path 33 downstream of the measuring section 4 and the fixed displacement pump 1
A bypass flow path 39 for communicating with the suction side is formed, an on-off valve 22 is provided in the middle of the bypass flow path 39, and a downstream side of the bypass flow path 39 branch position of the supply flow path 33,
The supply passage 33 is closed by the pressure P2 when the on-off valve 22 is opened by being urged by the spring 14 in the direction in which the supply passage 33 is closed, so that the fuel supply to the combustion chamber of the gas turbine engine 42 can be stopped. Shut-off valve 13
Is provided.

In the drawing, reference numeral 12 denotes a seal mounted on the large-diameter piston portion 2b, 23 denotes a position detector for detecting the position of the measuring piston 2, and PM denotes a pressure between the throttle 5 and the proportional solenoid valve 7, PL indicates the pressure on the suction side of the constant displacement pump 1.

During operation of the gas turbine engine 42,
A current value applied to the proportional solenoid valve 7 is controlled based on a detection signal of the position detector 23 so that the metering piston 2 moves to a required position in response to the operation of a throttle lever (not shown). Is adjusted, whereby the pressure PM changes and the metering piston 2 moves to the required position.

As the measuring piston 2 moves, the opening of the measuring section 4 of the supply flow path 33 is adjusted.
The required amount of fuel is supplied to the combustion chamber of the gas turbine engine 42 in a state where the upstream and downstream differential pressure (P1-P2) of the measuring section 4 is kept constant by the differential pressure control device 35.

At a position where the metering section 4 is most throttled and the flow rate of the fuel is at a minimum, the metering piston 2 abuts on the adjusting screw 3 toward the rightmost side in FIG. This position is adjusted to the minimum level required when the gas turbine engine 42 is started by the starter, and the fuel supply amount at this position is smaller than that required for the gas turbine engine 42 to operate independently. In this position, the idling state of the gas turbine engine 42 cannot be maintained.

Further, when the power supply is stopped, the flapper 8 of the proportional solenoid valve 7 is opened, and by the action of the throttle 5, the PM falls below a value obtained by multiplying the area ratio of the small-diameter piston portion 2a and the large-diameter piston portion 2b of the measuring piston 2 by P1. Then, the balance of the force acting on the metering piston 2 is lost, and the metering piston 2 moves to a position where it abuts the adjusting screw 3 so that only the minimum fuel flow rate is supplied to the gas turbine engine 42. The gap between the flapper 8 of the proportional solenoid valve 7 and the nozzle 6 or the throttle 5 is adjusted in advance so as to stop the operation and prevent a serious accident such as overspeed due to the inability to control the gas turbine engine 42.

In the event that some trouble occurs in the gas turbine engine 42 and there is a danger of a flame or the like unless the supply of fuel to the gas turbine engine 42 is stopped, the on-off valve 22 is opened and the supply flow path is opened. When the fuel 33 flows out to the suction side of the constant displacement pump 1, the pressure P <b> 2 decreases, the shutoff valve 13 closes, and no fuel is supplied to the gas turbine engine 42.

[0014]

Generally, the gas turbine engine 42 is allowed to idle for several minutes (minimum self-sustained rotation speed: usually 60 rotations of the maximum rotation speed) in order to prevent damage to the gas turbine engine 42 due to sudden thermal stress. (~ 70%), and after cooling, it is necessary to stop.

However, in the fuel flow control device for a gas turbine engine as described above, when the supply of electric power is stopped, the gas turbine engine 42 is suddenly stopped. And the possibility of damaging the gas turbine engine 42 was high.

In view of such circumstances, the present invention provides a gas turbine engine fuel flow control device capable of preventing a gas turbine engine from being damaged due to thermal stress without suddenly stopping the gas turbine engine even when power supply is stopped. It is something to offer.

[0017]

SUMMARY OF THE INVENTION The present invention provides a constant displacement pump driven by a gas turbine engine, a circulation passage connecting the discharge side and the suction side of the constant displacement pump, A proportional solenoid valve provided at a required position on the discharge side of the constant displacement pump and having a nozzle and a flapper capable of opening and closing the nozzle; a throttle provided upstream of the proportional solenoid valve in the circulation flow path; A measuring piston having a small-diameter piston portion movably inserted and a large-diameter piston portion slidably inserted into a large-diameter cylinder portion at both ends; and a slidably movable head side chamber of the large-diameter cylinder portion. A piston which is inserted and partitions the head side chamber into a first head side chamber on the side opposite to the large diameter piston portion and a second head side chamber on the side of the large diameter piston portion;
An adjusting screw for restricting movement of the piston toward the non-large-diameter piston portion; a stopper for restricting movement of the piston toward the large-diameter piston portion; a throttle for the head-side chamber of the small-diameter cylinder portion and the circulation passage; A balance flow path that communicates with the constant-capacity pump discharge side on the upstream side, a second head side chamber of the large-diameter cylinder portion, and a balance flow path that communicates a position between the throttle and the proportional solenoid valve of the circulation flow path. A connecting flow path for communicating the rod-side chamber of the large-diameter cylinder section with the constant-volume pump suction side of the circulation flow path; and a first head-side chamber of the large-diameter cylinder section, the circulation flow path during normal operation. An electromagnetic switching valve that can communicate with the constant-volume pump suction side of the circulation flow path when the supply of power is stopped, to the constant-capacity pump discharge side upstream of the throttle, and the electromagnetic switching valve and the large-diameter cylinder portion. One head An adjustment throttle provided in the middle of the flow path connecting the side chamber, and a branch from the fixed-displacement pump discharge side upstream of the throttle of the circulation flow path, communicating with the combustion chamber of the gas turbine engine, and moving the metering piston. And a supply flow path having a measuring section whose opening is adjusted in accordance with the above.

[0018]

Therefore, when starting the gas turbine engine,
When the electromagnetic switching valve is energized, the pressure in the first head side chamber of the large-diameter cylinder becomes equal to the pressure on the suction side of the constant displacement pump,
At this time, the pressure receiving areas at both ends of the piston are the same, and the pressure of the second head side chamber becomes larger than the pressure of the first head side chamber, and the piston moves to a position where it abuts on the adjustment screw. If appropriately adjusted in advance, at the position where the metering piston comes into contact with the piston, the minimum fuel flow required when the gas turbine engine is started by the starter is secured, and the gas turbine engine is started by the starter.

When the gas turbine engine is started and the power supply is stopped in a normal operation state, the power is not supplied to the electromagnetic switching valve, the electromagnetic switching valve is switched, and the first head side chamber of the large-diameter cylinder portion is switched. Pressure becomes equal to the pressure on the discharge side of the constant displacement pump, becomes larger than the pressure on the second head side chamber, the piston moves to the position where it abuts the stopper, and at the same time, the energization of the proportional solenoid valve is stopped, The pressure of the second head side chamber of the small-diameter cylinder decreases due to the action of the throttle, and the force applied to the small-diameter piston becomes greater than the force applied to the large-diameter piston. Since the pressure rise of the second head side chamber is also set in advance so that the forces applied to both ends of the measuring piston by the adjustment throttle are equal, As soon as the stone hits the stopper, the measuring piston always moves to the piston side and hits the piston, where the pressure of the head side chamber of the small diameter cylinder and the pressure of the first head side chamber of the large diameter cylinder are both constant capacity type. Although the pressure is equal to the pressure on the pump discharge side, the pressure receiving area of the small-diameter piston portion is smaller than the pressure receiving area of the piston on the first head side chamber side, so that the piston does not move while being in contact with the stopper. If the position is appropriately set in advance, the minimum fuel flow required for the gas turbine engine to operate independently is ensured at the position where the metering piston contacts the piston, and the gas turbine engine is held in an idling state.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention.
In the figure, portions denoted by the same reference numerals as those in FIG. 3 represent the same items.

The head-side chamber 27 of the large-diameter cylinder portion 26 is expanded by a required amount toward the rod-side chamber 31 so that the head-side chamber 27 is larger than the first head-side chamber 27a on the side of the non-large-diameter piston portion 2b. A piston 15 for partitioning into a second head side chamber 27b on the side of the radial piston portion 2b is slidably fitted, and the piston 1 is inserted into the second head side chamber 27b.
A stopper 17 is provided to limit the movement of the first large-diameter cylinder 5 toward the large-diameter piston portion 2b, and the first head-side chamber 27a of the large-diameter cylinder portion 26 is moved to a constant volume upstream of the throttle 5 in the circulation flow path 24 during normal operation. An electromagnetic switching valve 18 is provided on the discharge side of the type pump 1 so as to be able to communicate with the suction side of the constant displacement type pump 1 of the circulation channel 24 when the power supply is stopped, and connects the electromagnetic switching valve 18 to the first head side chamber 27a. The adjustment throttle 19 is provided in the middle of the flow path 40.

The second head side chamber 27b of the piston 15
A projection 15a is formed on the end face on the side of the measuring piston 2. As shown in FIG. 2, the large-diameter piston 2b of the measuring piston 2 is connected to the projection 1 with the piston 15 in contact with a stopper 17, as shown in FIG.
5a so that the idling state of the gas turbine engine 42 can be maintained.
And the length of the projection 15a are set.

Also, on the outer periphery of both ends of the piston 15,
The seals 16 and 20 are attached and the piston 15
An annular groove 41 is provided at a position between the seals 16 and 20 on the outer periphery.
The flow path 21 is connected to the large-diameter cylinder 26 so that the pressure in the annular groove 41 is always equal to the pressure PL on the suction side of the constant displacement pump 1.

Next, the operation of the above embodiment will be described.

When starting the gas turbine engine 42,
As shown in FIG. 1, the electromagnetic switching valve 18 is energized, and the pressure PB of the first head side chamber 27 a of the large-diameter cylinder portion 26 becomes equal to the pressure PL on the suction side of the constant displacement pump 1. The pressure receiving area is the same, the pressure PT (= PM) of the second head side chamber 27b becomes PT> PB, and the piston 15 moves to a position where it abuts the adjustment screw 3, so that the protrusion amount of the adjustment screw 3 is appropriately adjusted in advance. If this is done, the measuring piston 2 will be
With the flapper 8 open so as to abut the gas turbine engine, the minimum fuel flow required when the starter starts the gas turbine engine 42 is secured, and the gas turbine engine 42 is started by the starter.

When the gas turbine engine 42 is started and enters a normal operation state, the piston 15 is held at the position shown in FIG. 1, and in this state, the metering piston 2 is required according to the operation of a throttle lever (not shown). To the position, the degree of opening of the measuring section 4 of the supply flow path 33 is adjusted, and the upstream and downstream differential pressure (P1-P2) of the measuring section 4 of the supply flow path 33 is kept constant by the differential pressure control device 35. In this state, a required amount of fuel is supplied to the combustion chamber of the gas turbine engine 42.

On the other hand, when the power supply is stopped, the electromagnetic switching valve 18 is not energized, and the electromagnetic switching valve 18 switches to the position shown in FIG. The pressure PB in one head side chamber 27a becomes equal to the pressure P1 on the discharge side of the constant displacement pump 1, and PB (= P1)
> PT (= PM), and the piston 15 becomes the stopper 1
Move to the position where it hits 7.

At the same time, the power supply to the proportional solenoid valve 7 is stopped.
The flapper 8 opens and the PM decreases due to the action of the diaphragm 5,
Since the force applied to the small-diameter piston portion 2a of the measuring piston 2 is set to be greater than the force applied to the large-diameter piston portion 2b, the measuring piston 2 moves toward the piston 15 and the projecting portion 15a of the piston 15 Hit it.

Here, the pressure in the head side chamber 28 of the small diameter cylinder section 25 and the first head side chamber 27 of the large diameter cylinder section 26
a is equal to the pressure P1 on the discharge side of the constant displacement pump 1, but since the pressure receiving area of the small diameter piston portion 2a is smaller than the pressure receiving area of the piston 15 on the first head side chamber 27a side, the piston 15 It does not move while in contact.

During the movement of the piston 15, the pressure PM increases due to the pushed fuel.
9, the movement speed of the piston 15 is limited to prevent an increase in fuel (overspeed) due to an increase in the pressure PM, and the metering piston 2 generated when the movement speed of the piston 15 is excessively limited. The movement of the measuring piston 2 is stopped only during the movement of the piston 15, so that the measuring piston 2 is stopped.
The metering piston 2 does not fall below the idle fuel position before hitting the stopper 17.

Accordingly, if the position of the stopper 17 and the length of the projection 15a are appropriately set in advance, the gas turbine is located at the position where the measuring piston 2 contacts the projection 15a of the piston 15 as shown in FIG. The minimum fuel flow required for the self-sustaining operation of the engine 42 is ensured, and the gas turbine engine 42 is kept idling.

The adjusting throttle 19 governs the moving speed of the piston 15 as described above. By setting the adjusting throttle to an appropriate area in advance, the electric power is controlled during the period from the start of the gas turbine engine 42 to the idling state. Even when the supply is stopped or the electromagnetic switching valve 18 is disconnected, it is possible to suppress a rapid change in the fuel flow rate and to prevent the gas turbine engine 42 from stalling.

In this way, the sudden stop of the gas turbine engine 42 when the power supply is stopped can be avoided without affecting other functions required as the fuel flow control device for the gas turbine engine, and the gas stress due to thermal stress can be prevented. Damage to the turbine engine 42 can be prevented.

It should be noted that the fuel flow control device for a gas turbine engine of the present invention is not limited to the above-described embodiment, but can be applied to a case where it is desired to set a two-stage minimum fuel flow for some other reason. Yes, for example, when applied to a jet engine mounted on an aircraft, various changes can be made without departing from the gist of the present invention, such as being able to maintain a certain rotation state without stopping the engine when power is cut off due to a lightning strike or the like. Obviously you can get it.

[0036]

As described above, according to the fuel flow control device for a gas turbine engine of the present invention, a sudden stop of the gas turbine engine can be avoided even when the power supply is stopped, and damage to the gas turbine engine due to thermal stress can be prevented. An excellent effect that it can be prevented can be obtained.

[Brief description of the drawings]

FIG. 1 is a system diagram during normal operation of one embodiment of the present invention.

FIG. 2 is a system diagram when power supply is stopped according to an embodiment of the present invention.

FIG. 3 is a system diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Constant displacement pump 2 Metering piston 2a Small diameter piston part 2b Large diameter piston part 3 Adjusting screw 4 Metering part 5 Throttle 6 Nozzle 7 Proportional solenoid valve 8 Flapper 15 Piston 17 Stopper 18 Electromagnetic switching valve 19 Adjusting throttle 24 Circulation flow path 25 Small diameter Cylinder section 26 Large-diameter cylinder section 27 Head side chamber 27a First head side chamber 27b Second head side chamber 28 Head side chamber 29, 30 Balance flow path 31 Rod side chamber 32 Connection flow path 33 Supply flow path 40 Flow path 42 Gas turbine engine

Claims (1)

(57) [Claims] 1. A fixed displacement pump driven by a gas turbine engine, a circulation passage connecting a discharge side and a suction side of the constant displacement pump, and a required position of the fixed displacement pump discharge side of the circulation passage. A proportional solenoid valve having a nozzle and a flapper capable of opening and closing the nozzle, a throttle provided upstream of the proportional solenoid valve in the circulation flow path, and a small diameter slidably fitted in the small diameter cylinder portion. A measuring piston having a piston portion and a large-diameter piston portion slidably fitted into the large-diameter cylinder portion at both ends; and a measuring-side piston slidably fitted into the head-side chamber of the large-diameter cylinder portion, and A piston partitioning into a first head chamber on the side of the large-diameter piston section and a second head chamber on the side of the large-diameter piston section, an adjusting screw for restricting movement of the piston to the side opposite to the large-diameter piston section, To diameter piston side A stopper for restricting the movement of the small-diameter cylinder section, a balance flow path for communicating the head-side chamber of the small-diameter cylinder section with the fixed-capacity pump discharge side upstream of the throttle of the circulation flow path, and a second head of the large-diameter cylinder section. A balance flow path that allows the side chamber to communicate with the position between the throttle and the proportional solenoid valve of the circulation flow path, and a connection flow that allows the rod side chamber of the large-diameter cylinder to communicate with the constant volume pump suction side of the circulation flow path. Path, the first head side chamber of the large diameter cylinder portion,
An electromagnetic switching valve that can be connected to the constant-displacement pump discharge side upstream of the throttle of the circulation flow path during normal operation, and to the constant-displacement pump suction side of the circulation flow path when power supply is stopped;
An adjusting throttle provided in the middle of a flow path connecting the electromagnetic switching valve and the first head-side chamber of the large-diameter cylinder portion; and a gas turbine branching from a discharge side of a fixed displacement pump upstream of the throttle of the circulation flow channel. A fuel flow control device for a gas turbine engine, comprising: a supply passage communicating with a combustion chamber of the engine and having a measuring section whose opening is adjusted in accordance with movement of the measuring piston.