JP2003020959A - Fuel flow control device with emergency speed reducing function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel flow control device with an emergency speed reducing function capable of injecting fuel flow in proportion to the displacement of a nozzle flapper during normal operation and urgently decelerating an engine with less time lag and a high response at the time of excessive rotational speed. SOLUTION: An over-speed valve 10 capable of switching a flow passage resistance into large and small modes is installed in a pressurized feel line ranging from a fuel pump 1 to a nozzle 4. The over-speed valve 10 comprises a flow-passage switching valve 11 for selectively switching an inflow port 10a to two branch flow passages 10b and 10c and a resistance generating body 12 allowing to flow from the first branch flow passage 10b to an outflow port 10d with a small pressure loss and to flow from the second branch flow passage 10c to the outflow port 10d with a large pressure loss. The resistance generating body 12 is a swirl chamber having a cylindrical hollow.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel flow rate control device for rapidly increasing / decreasing a fuel flow rate with little time lag and high responsiveness at the time of rapid acceleration / deceleration.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of a conventional fuel flow rate control device for injecting fuel into a combustor of a jet engine. In this figure, 1 is a fuel pump, 2 is a metering valve, 3 is a drain valve, 4 is a nozzle, and liquid fuel (jet fuel) pressurized by the fuel pump 1 is metered (flow rate adjusted) by the metering valve 2. , Open the drain valve 3,
It is designed to inject from a nozzle 4 to a combustor (not shown).

Further, a bypass valve 5 for returning excess fuel to the upstream side of the fuel pump 1, and a control of the bypass valve 5, the difference between the upstream pressure P ₁ and the downstream pressure P ₂ of the metering valve 2 is controlled. The differential pressure sensor valve 6 controls the pressure ΔP to be constant.

The metering valve 2 has a metering spool 2a and a nozzle flapper 2b. By moving the nozzle flapper 2b electrically or mechanically (left and right in the figure), the fluid pressure acting on the left end of the metering spool 2a is changed. Then, the measuring spool 2a is moved to the left and right to control the passing flow rate. For example, when the nozzle flapper 2b is moved to the right in this figure, the left end pressure of the measuring spool 2a rises, the measuring spool 2a moves to the right and throttles the flow rate, and conversely, when the nozzle flapper 2b is moved to the left, The pressure at the left end of 2a decreases, the metering spool 2a moves to the left, and the flow rate increases.

The metering valve 2 maintains a constant differential pressure ΔP between the upstream pressure P ₁ and the downstream pressure P ₂ , so that the flow rate of passage is proportional to the displacement of the nozzle flapper 2b. Therefore, the spool 6a of the differential pressure sensor valve 6 is biased to the left side in the drawing by the spring 6, and the upstream pressure P ₁ is introduced to the left end of the spool 6a and the downstream pressure P ₂ is introduced to the right end of the spool 6a by the pilot lines 7a and 7b, respectively. There is.

When the differential pressure ΔP becomes smaller than a predetermined value, the spool 6a moves to the left in this figure, and the pilot line 8
High-pressure (upstream pressure P ₁ ) fuel flows from a to 8b, the spool 5a of the bypass valve 5 is moved to the right to close the bypass line 9b, and the upstream pressure P ₁ is increased to increase the metering valve 2
Increase the flow rate of

On the contrary, when the differential pressure ΔP becomes larger than a predetermined value, the spool 6a moves to the right in this figure, and the pressure on the spring 5b side of the bypass valve 5 is adjusted to the pilot lines 8b, 8c.
Via the fuel pump 1 to the upstream side (low pressure portion), the spool 5a of the bypass valve 5 is moved to the left to open the bypass line 9b, and the upstream pressure P ₁ is lowered to reduce the flow rate of the metering valve 2. .

With the above-described structure, the differential pressure sensor valve 6 always maintains the differential pressure ΔP between the upstream pressure P ₁ and the downstream pressure P ₂ constant, and the fuel flow rate proportional to the displacement of the nozzle flapper 2b is injected from the nozzle 4. You can do it.

[0009]

However, in the above-described conventional fuel flow rate control device, even if the jet flapper 2b is abruptly changed in displacement when the jet engine is over-rotating (at the time of overspeed) to decelerate, the above-mentioned difference occurs. Due to the action of the pressure sensor valve 6, there is a problem that the response of the fuel flow rate is poor.

That is, in the circuit of FIG. 3, even if the nozzle flapper 2b is rapidly moved to the right and the metering spool 2a is moved to the right, the bypass valve 5 is in the semi-closed position, so the fuel flow rate does not immediately decrease. . After that, the differential pressure ΔP between the upstream pressure P ₁ and the downstream pressure P ₂ increases, the spool 6a moves to the right, the high pressure fuel returns from the pilot lines 8b to 8a, and the spool 5a of the bypass valve 5 moves to the left. Only after the bypass line 9b is opened, the flow rate of the metering valve 2 decreases. Therefore, in the conventional fuel flow rate control device, the responsiveness of the metering valve determines the responsiveness of the fuel control system, and it is not possible to perform control to suddenly change the fuel flow rate beyond the responsiveness of the metering valve. There was a problem that a time lag occurred when suddenly decelerating.

In other words, in the conventional fuel flow rate control device, in order to control the flow rate, two mechanisms are required: (1) keeping the differential pressure constant and (2) throttling the variable throttle. It is impossible to control the fuel even without it. Therefore, there is a problem in that it is difficult to perform emergency deceleration at the time of over-rotation (at the time of overspeed) that may damage the engine while keeping this mechanism alive.

The present invention was created to solve such problems. That is, an object of the present invention is to provide a fuel with an emergency deceleration function capable of injecting a fuel flow rate proportional to the displacement of the nozzle flapper during normal operation and capable of emergency decelerating the engine with high response with a small time lag during overspeed. It is to provide a flow control device.

[0013]

According to the present invention, a fuel pump (1) for pressurizing a liquid fuel, a metering valve (2) for metering the pressurized fuel and supplying it to a combustor, are pressurized. A metering valve measures the liquid fuel pressurized by the fuel pump, including a bypass valve (5) for returning the fuel to the upstream side of the fuel pump and returning it, and a differential pressure sensor valve (6) for controlling the bypass valve. In the fuel flow rate control device for injecting from the nozzle (4), the pressurized fuel line from the fuel pump (1) to the nozzle (4) is provided with an overspeed valve (10) capable of switching the flow path resistance between large and small. A fuel flow rate control device with an emergency deceleration function is provided.

According to this structure of the present invention, the overspeed valve (10) provided in the pressurized fuel line from the fuel pump (1) to the nozzle (4) is provided with a flow path resistance that is small during normal operation. By so doing, it is possible to inject a fuel flow rate proportional to the displacement of the nozzle flapper as in the conventional case. Further, by switching the overspeed valve (10) to the one having a larger flow path resistance at the time of over-rotation, the flow rate can be instantaneously reduced, and the engine can be urgently decelerated with high responsiveness with little time lag.

According to a preferred embodiment of the present invention, the overspeed valve (10) comprises an inlet (10a).
And a first branch flow channel (10) for selectively switching the two branch flow channels (10b, 10c).
b) to the outlet (10d) with a small pressure drop, and from the second branch flow path (10c) to the outlet (10d) with a large pressure drop, the resistance generator (12).
Is a swirl chamber having a cylindrical cavity, and the swirl chamber has a first opening (12a) which is provided in the axial center thereof and communicates with the first branch flow passage, and a cylindrical cavity at the first inlet. A second opening (12b) which is provided so as to face each other and which communicates with the outlet.
And a third opening (12c) provided in the outer peripheral portion of the cylindrical cavity in the tangential direction and communicating with the second branch flow path.

With this configuration, during normal operation, the flow path switching valve (11) is set to the first branch flow path (10b) side, so that the first branch flow path (1) flows from the inflow port (10a).
0b), the first opening (12a) and the second opening (12b) provided opposite to the first opening (12a), it is possible to flow to the outlet (10d) with a small pressure loss. In addition, by switching the flow path switching valve (11) to the side of the second branch flow path (10c) during over-rotation, the third opening (12c) from the inflow port (10a) through the second branch flow path (10c). To the inside of the cylindrical cavity of the resistance generator (12), the fuel is tangentially injected from the outer peripheral portion to generate a vortex and generate a pressure loss proportional to the square of the flow rate. The flow rate can be instantaneously reduced by causing a large pressure loss to flow through the two openings (12b) to the outlet (10d).

The overspeed valve (10) is provided between the differential pressure sensor valve (6) and the two pilot lines (7a, 7b) communicating with the pressurized fuel line.
It is preferable. With this configuration, the differential pressure of the pilot lines (7a, 7b) increases in accordance with the switching of the overspeed valve (10) to the one having a larger flow path resistance,
The differential pressure sensor valve (6) can be operated with a small time lag.

The overspeed valve (1
0) is provided between the fuel pump (1) and the metering valve (2), and may further include a relief valve (14) for returning the pressurized fuel on the downstream side of the fuel pump (1) to the upstream side. . With this configuration, fuel returns from the relief valve (14) to the pump inlet in accordance with the pressure loss generated by switching the overspeed valve (10), so that only a fixed amount of fuel is supplied to the engine.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings. In each drawing, common portions are denoted by the same reference numerals, and redundant description will be omitted.

FIG. 1A is a block diagram of a fuel flow rate control device with an emergency deceleration function according to the present invention. In this figure, a fuel flow rate control device with an emergency deceleration function according to the present invention comprises a fuel pump 1 for pressurizing liquid fuel, and a metering valve 2 for metering the pressurized fuel and supplying it to a combustor (not shown).
The fuel pump 1 includes a bypass valve 5 for bypassing and returning the pressurized fuel to the upstream side of the fuel pump 1, and a differential pressure sensor valve 6 for controlling the bypass valve 5.
The liquid fuel pressurized by the
It is designed to jet from. This configuration is similar to the conventional device illustrated in FIG.

The fuel flow rate control device with an emergency deceleration function of the present invention further includes an overspeed valve 10 in the pressurized fuel line from the fuel pump 1 to the nozzle 4, which can switch the flow passage resistance between large and small.

As shown in FIG. 1B, the overspeed valve 10 has an inlet 10a and two branch passages 10a.
b, 10c alternative flow path switching valve 11
And a resistance generator 12 that flows from the first branch flow channel 10b to the outflow port 10d with a small pressure loss and flows from the second branch flow channel 10c to the outflow port 10d with a large pressure loss. Flow path switching valve 11
Is provided with a spool moving means (not shown) for instantaneously moving the spool 11a provided therein during over-rotation. The spool moving means is, for example, an electromagnetic solenoid that operates in response to an emergency cutoff signal.

FIG. 2 is a diagram for explaining the operation of the overspeed valve of the present invention. In this figure, (A) is a normal operation state, (B) is an emergency cutoff state, and (C) is a resistance generator 1.
2 is a diagram showing contour lines of equiangular momentum in FIG. 2, and (D) is a diagram showing streamlines in the resistance generator 12. FIG. As shown in FIGS. 2A to 2D, the resistance generator 12 is a swirl chamber having a cylindrical cavity. The swirl chamber 12 communicates with a first opening 12a that is provided at the axis of the swirl chamber 12 and that communicates with the first branch flow passage 10b, and a first opening 12a that faces the first inflow port 12a with a cylindrical cavity in between and that faces the outflow port 10d. It has the 2nd opening 12b and the 3rd opening 12c which is provided in the outer peripheral part of a cylindrical cavity toward the tangential direction, and communicates with the 2nd branch flow path 10c.

That is, the overspeed valve 10
Is the swirl chamber 12 and the flow paths 10a, 10b, 10c, 10d.
And a switching valve 11. The swirl chamber 12 has a structure in which the fluid flows tangentially into the cylindrical hollow chamber. As shown in FIG. 2C, since the fluid has the same angular momentum at the time of inflow and in the vicinity of the orifice according to the law of conservation of angular momentum, it has a large rotational velocity near the orifice having a small radius of rotation. Further, since its velocity energy is orthogonal to the flow of the pipe line of the inflow port 10a and the outflow port 10d, it does not recover to an effective pressure but it changes to heat as it is and turns into a pressure loss. On the other hand, when the fluid is introduced from the inflow port 10a at the center of the swirl chamber, the fluid flows vertically into the orifice, so that no pressure loss higher than that of the orifice formula occurs. That is, if the inflow port 10a and the outflow port 10d have substantially the same diameter as the diameter of the pipe, almost no pressure loss occurs.

Therefore, with this configuration, during normal operation,
As shown in FIG. 2 (A), the flow path switching valve 11 is set to the first branch flow path 10b side (right side in the figure), so that the first branch flow path 10b and the first opening 12a are provided from the inflow port 10a.
Through the second opening 12b provided opposite to
It is possible to flow to the outlet 10d with a very small pressure loss. Further, at the time of over-rotation, as shown in FIG. 2 (B), the flow path switching valve 11 is connected to the second branch flow path 10c side (left side in the drawing).
By switching to the resistance generator 12 from the inflow port 10a through the second branch flow channel 10c to the third opening 12c.
The fuel is injected tangentially from the outer peripheral portion into the inside of the cylindrical cavity of the (vortex flow chamber) to generate a vortex flow to generate a pressure loss proportional to the square of the flow rate, and the second loss 12b in a direction orthogonal to the vortex flow. It is possible to make a large pressure loss flow to the outlet 10d via the and reduce the flow rate instantaneously.

In the example of FIG. 1A, the overspeed valve 10 is provided between two pilot lines 7a and 7b which connect the differential pressure sensor valve 6 and the pressurized fuel line. By providing the overspeed valve 10 at this position, when the overspeed valve 10 is switched to the one having a larger flow path resistance at the time of overspeed, the pressure in the pilot line 7b sharply decreases, and the differential pressure sensor valve 6
Is operated to the right in the figure with a small time lag, high-pressure fuel returns from the pilot lines 8b to 8a, the spool 5a of the bypass valve 5 is moved to the left to open the bypass line 9b, and the flow rate of the metering valve 2 is decreased. That is, the flow rate is instantly directly reduced by the overspeed valve 10, the spool 5a of the bypass valve 5 is moved to the left in a short time to return excess fuel, and the differential pressure ΔP is shortened to a predetermined constant value. Can be returned in time.

As shown by the chain double-dashed line in FIG. 1 (A), an overspeed valve 10 is provided between the fuel pump 1 and the metering valve 2, and the pressurized fuel on the downstream side of the fuel pump 1 is upstream. A relief valve 14 that returns to the side may be provided.
In this case, if the overspeed valve 10 is switched to the one having a larger flow path resistance during overspeed, an excessive pressure loss occurs before and after the fuel pump 1, but the fuel returns from the relief valve 14 to the pump inlet in response to this pressure loss. Therefore, a certain amount of fuel can be supplied to the engine.

As described above, according to the configuration of the present invention, the overspeed valve 10 provided in the pressurized fuel line from the fuel pump 1 to the nozzle 4 is
By making the flow path resistance smaller, it is possible to inject a fuel flow rate proportional to the displacement of the nozzle flapper as in the conventional case. Further, by switching the overspeed valve 10 to the one having a larger flow path resistance during overspeed, the flow rate can be instantaneously reduced, and the engine can be urgently decelerated with high responsiveness with little time lag.

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the gist of the invention.

[0030]

As described above, according to the present invention, downstream of the pump that discharges fuel in proportion to the engine speed,
A vortex flow generation disk that causes a pressure loss in proportion to the square of the flow rate is inserted, and a switching valve can switch between the case where the pressure loss occurs and the case where the pressure loss does not occur.
As a result, the fuel returns from the relief valve to the pump inlet according to the pressure loss, so that only a fixed amount of fuel is supplied to the engine. Therefore, the fuel supplied to the engine can be determined only by the engine speed and the switching valve, and the device can be simplified.

That is, the fuel flow rate control device with the emergency deceleration function of the present invention can inject the fuel flow rate proportional to the displacement of the nozzle flapper during the normal operation, and can urge the engine with high responsiveness with a small time lag at the time of excessive rotation. It has an excellent effect such as being able to decelerate.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a fuel flow rate control device with an emergency deceleration function according to the present invention.

FIG. 2 is an operation explanatory view of the overspeed valve in the present invention.

FIG. 3 is a configuration diagram of a conventional fuel flow rate control device.

[Explanation of symbols]

1 fuel pump, 2 metering valve, 3 drain valve, 4 nozzle, 5 bypass valve, 6 differential pressure sensor valve, 7a, 7b pilot line, 8a, 8
b, 8c Pilot line, 9a, 9b Bypass line, 10 Overspeed valve, 10a Inlet, 10b, 10c Branch flow passage, 10d Outlet, 12
Resistance generator (vortex chamber), 12a First opening, 12b
2nd opening, 12c 3rd opening, 14 relief valve

Claims (4)

[Claims] 1. A fuel pump (1) for pressurizing a liquid fuel.
A metering valve (2) for metering the pressurized fuel to supply it to the combustor, a bypass valve (5) for bypassing the pressurized fuel to the upstream side of the fuel pump and returning it, and controlling this bypass valve. Equipped with a differential pressure sensor valve (6),
In a fuel flow rate control device in which liquid fuel pressurized by a fuel pump is metered by a metering valve and injected from a nozzle (4), a flow path resistance is applied to a pressurized fuel line from the fuel pump (1) to the nozzle (4). A fuel flow rate control device with an emergency deceleration function, comprising an overspeed valve (10) that can be switched between large and small. 2. The overspeed valve (10)
Has two branch flow paths (10b, 10).
a flow path switching valve (11) for selectively switching to c),
Flow from the first branch flow path (10b) to the outlet (10d) with a small pressure loss, and from the second branch flow path (10c) to the outlet (10c).
and a resistance generator (12) flowing with a large pressure loss up to d), the resistance generator (12) is a swirl chamber having a cylindrical cavity, and the swirl chamber is provided at the axial center of the swirl chamber. A first opening (12a) communicating with the branch flow passage, a second opening (12b) facing the first inlet with a cylindrical cavity in between and communicating with the outlet, and an outer periphery of the cylindrical cavity. The fuel flow rate control device with an emergency deceleration function according to claim 1, further comprising a third opening (12c) provided in a portion in a tangential direction and communicating with the second branch flow passage. 3. The overspeed valve (10)
Is provided between two pilot lines (7a, 7b) that connect the differential pressure sensor valve (6) and the pressurized fuel line, and the fuel flow rate control with an emergency deceleration function according to claim 1. apparatus. 4. The overspeed valve (10)
Is provided between the fuel pump (1) and the metering valve (2), and further comprises a relief valve (14) for returning the pressurized fuel on the downstream side of the fuel pump (1) to the upstream side. The fuel flow rate control device with an emergency deceleration function according to claim 1.