JPS6022067A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To permit to obtain a good atomizing characteristic even in a low flow amount area by a method wherein a fuel return path is opened at the opposite position of a nozzle in an eddy-current chamber and a fuel amount control mechanism is provided in the same path in the fuel injection valve equipped with the eddy-current chamber. CONSTITUTION:The fuel injection valve 1 in a gas turbine engine is constituted by forming the first eddy-current chamber 26 between a vortex plate 16 and a valve body 18 and the second eddy-current chamber 28 between a vortex holder 14 and the eddy-current chamber 26 in the lower part thereof while both chambers 26, 28 are communicated mutually through a nozzle 30. In this case, a relief opening 185 is formed on the wall surface opposite to the nozzle 30 in the eddy- current chamber 26 while the opening 185 is communicated with a return pipe through a reverse flow preventing valve 80, a choking member 74, a hole 20, paths 105, 106, a horizontal hole 382 or the like. The choking member 74 is provided with an orifice 741, setting the amount of fuel to be returned from the eddy-current chamber 26, at the lower end face thereof.

Description

TECHNICAL FIELD The present invention relates to a fuel injection valve, in particular a fuel injection valve with a swirl chamber suitable for gas turbine engines.

In prior art gas turbine engines, fuel injection valves with swirl chambers are often used. This type of fuel injection valve has excellent atomization performance, but its usable flow rate range is narrow. That is, the injection flow rate Q is proportional to the square root of the pressure difference Δp before and after.

Therefore, in order to widen the flow range, the pressure difference Δp must be increased. This means that the pressure on the inlet side must be varied over a wide range, from high pressure at high flow rates to low pressure at low flow rates.

However, when the pressure on the inlet side is lowered, the velocity of the swirling flow in the vortex chamber, that is, the strength of the vortex decreases, which increases the thickness of the liquid film from the nozzle and increases the particle size of the spray. As a result, the atomization state becomes poor and it does not function satisfactorily at low flow rates. If the required flow rate range of the fuel injection valve is narrow, it would be possible to make the pressure difference △p sufficiently large by reducing the size of the inlet to the swirl chamber, but this is subject to the above two restrictions. . In any case, fuel injection valves with a swirl chamber are not suitable for low flow rates.

Purpose of the Invention The present invention has been made in view of the above-mentioned drawbacks of the prior art, and provides a vortex chamber that can provide sufficiently good atomization characteristics even in a low flow rate range, and as a result can be adapted to a wide range of required flow rates. A] object of the present invention is to provide a fuel injection valve.

Structure of the Invention The fuel injection valve equipped with a swirl chamber of the present invention has a fuel return passage opened at a position opposite to the nozzle that enters the swirl chamber, and a flow rate control mechanism having a flow rate control throttle in the fuel return passage. It is made by installing. A portion of the fuel is returned from the swirl chamber through the flow control restriction, and in order to obtain the required injection amount, the amount of incoming fuel must be increased by that amount, and the flow rate can be increased accordingly. As a result, the swirling flow within the vortex chamber is relatively strengthened and atomization can be improved.

EXAMPLE Below, an example will be described. In FIG. 1, reference numeral 1 denotes a fuel injection valve, which is attached to a wall surface 2 of a combustion chamber of a gas turbine engine. Fuel from the fuel tank 3 is introduced into a flow rate control device 5 by a pump 4. The flow control device supplies fuel at a pressure (flow rate) according to the engine operating conditions to the fuel injection valve I.
to be introduced via vibro. 7 returns excess fuel to the tank with a return pipe.

FIG. 2 specifically shows the structure of the fuel injection valve 1 of the present invention.

The embodiment shown in Fig. 2 has two large and small vortex chambers, and when the flow rate is small, the smaller vortex chamber takes charge of the injection, and when the flow rate is large, this vortex chamber and the larger vortex chamber take charge of the injection. This is an application of the present invention to the type. In the figure, 10 is a main body, and 12 is a nozzle holder. The nozzle boulder 12 has a cylindrical shape, and includes a portex boulder 14, a portex plate 16, and a valve body 18.
Then, valve plays 1 and 20 are sequentially inserted. In this inserted state, the main body 1o is inserted into the nostle main body 1 through the O ring 22.
2 and are mutually fastened by the outer cylinder 24. The flange 241 of the outer cylinder 24 serves as a mounting portion to the wall surface of the combustion chamber.

As shown enlarged in Figure 4, Portex Spray 1-
A first swirl chamber 26 is formed between the portex plate 16 and the valve body 18 , and a second swirl chamber 28 is formed between the portex plate 16 and the Borna 7x holder 14 below the first swirl chamber 26 . It is formed. The first swirl chamber 26 opens into the second swirl chamber 28 by a first jet orifice 30 . Additionally, the second swirl chamber opens into the combustion chamber of the gas turbine engine by means of a second jet orifice 32 . The first nozzle 30 is located above the second nozzle 32 so as to face it.

In FIG. 2, reference numeral 34 indicates a play plate having a fuel supply connector 36 and a fuel return connector 38. - and is fixed to the main body 10 by the cap 40 via the O-ring 41. The can knob 40 includes a cylindrical portion 401 that is fitted into the hole 101 of the main body 10, and a check valve 42 is installed within the knot portion 401. This check valve 42 is formed as a ball valve and is disposed between a valve seat 44 fitted into the cylindrical portion 401 and a spring seat 46. The spring 48 exerts a biasing force that causes the valve 42 to close the valve seat 44 when in use. The valve hole of the valve seat 44 communicates with the fuel hole 361 of the fuel supply connector 36 via a vertical hole 402 and a horizontal hole 403 in the cap 40. A fuel chamber 50 formed downstream of the check valve 42 includes a passage 102 in the main body 10, a passage 102 in the main body 10, and a passage between the main body 10 and the nozzle holder 1.
an annular passage 52 between the valve body 18, the valve plate 20, and the nozzle bolder 12; a fuel hole 181 in the valve body 18; an annular passage 56 between the valve body 1B and the Borna Tsux spray 116; It opens into the first swirl chamber 26 via the inlet 58 (the fourth
(see figure).

In FIG. 2, 60 is a control valve, which is configured as a ball valve. The control valve 60 is biased to seat on a valve seat 202 formed in the valve plate 20 by an adapter 64 that receives the force of a spring 62 .

The valve hole in the valve seat 202 opens into the annular passage 54 through a hole 204 in the valve plate 20 and receives fuel supply therefrom.

The space 66 above the valve seat I is a passage 206 in the valve plate, a fuel passage 184 in the valve body 18, and a passage 16j in the portex plate 16.

The second vortex chamber 28 via the annular passage 67 between the portex plate and the portex holder and the second inflow lower 0
(See Figure 4).

A first inlet 58 into the first swirl chamber 26 opens tangentially thereto, as schematically shown in FIG.

Similarly, the second inflow lower 0 into the second swirl chamber 28 is also open in the tangential direction thereof. It is well known that such a tangential L3 opening of the inlet 58 or 70 into the swirl chamber 26 or 28 causes a swirling flow in the swirl chamber 26 or 28.

According to the present invention, the vortex chamber 26 which takes charge of injection when the flow rate is small is provided with a relief opening 185 in the wall surface on the opposite side from the jet port 30. An opening 185 is drilled in the portex plate 16 to return some fuel from the swirl chamber 26 as described in 1 & above. By installing it on the side opposite to the nozzle 2G, part of the fuel can be returned without affecting the swirling flow within the swirl chamber 26 in the slightest. The vortex chamber 26 has an opening 185, a throttle member 74, a hole 207 in the valve plate 20, a main body 10, and a valve plate 2.
annular passage 76 between 0 and 105.1 in the body 10;
06, and 38 vertical holes in the fuel return connector 38,
It is connected to the pipe 7 in FIG. 1 via a horizontal hole 382. As shown in FIG. 2, the restricting member 74 is formed into a cup shape and is screwed into the bore 187 of the main body 18 and fixed therein. The restrictor member 74 has an orifice 741 on its lower end surface, which sets the amount of fuel to be returned from the swirl chamber 26.

The communication hole 185 that opens into the first swirl chamber 26 is provided with a second non-return valve 80 which, by means of a spring 82 and via an adapter 84, is prevented from closing the valve seat 188 adjacent to the communication hole 185. It is exerting a strong urging force.

To describe the operation of the device of the present invention described above, fuel from the flow control device y15 is introduced from the vibro to the fuel supply connector 36 of the fuel injection valve 1, and the fuel is introduced into the fuel supply connector 36 of the fuel injection valve 1 through the passage 361, the hole 403,
The check valve 42 is pushed open from 402 and enters the fuel chamber 50. From the chamber 50, fuel flows through passages 102°52, 54.18
．． 56 and enters the first swirl chamber 26 from the first inlet 58
is introduced tangentially into the flow, creating a swirling flow therein. The swirling fuel flow is sprayed from the first nozzle 30 through the second nozzle 32 into the combustion chamber in the form of a thin conical liquid film F (FIG. 7).

When the conical liquid film formed thinly in this way reaches a certain flight distance, it becomes finely atomized as shown in G.

The spray from the first vortex chamber 26 is responsible for spraying when the pressure of the fuel from the flow control device 5 is low, that is, in the low flow region, and its flow rate characteristics are determined by the inlet pressure (i.e., from the flow control device 5). Solid line 7 in Figure 6 for fuel pressure) p!
It is represented by 1. In this pressure state, the control valve 6
Since the fuel pressure acting on 0 is small, it is closed and no fuel is supplied to the second vortex chamber 28.

When the fuel pressure reaches the set value p1, the fuel pressure acting on the control valve 60 overcomes the spring 62 and the valve 60 moves away from the valve seat 202, and the fuel flows through the passages 206, 184, 161.67 to the second inlet lower 0. , and is tangentially introduced into the second swirl chamber 28 from this second inflow lower 0. Therefore, the second
A swirling flow of fuel is generated in the vortex chamber 28 and is sprayed from the nozzle 32 into the combustion chamber. In this case as well, the spray is formed as a thin conical liquid film stream as explained in FIG. In this manner, at high pressure, the spray from the second swirl chamber 28 is generated in addition to the spray from the first swirl chamber 26, and the flow rate characteristics are as shown in FIG. A curve like 12 is obtained by superimposing the flow rate characteristic from the second swirl chamber 28 on the flow rate characteristic.

The fuel pressure supplied in the first swirl chamber 26 acts on the ball 80 and displaces it from the valve seat 188 against the spring 82. That is, the first swirl chamber 26 includes the communication passage 185, the orifice 741, the passages 207, 105, 106, the hole 381.
It communicates with the return vibe 7 via 382. The return flow rate at this time is determined by the diameter of the orifice 741. As described above, since fuel is always flowing out from the first swirl chamber 26, the desired injection amount from the nozzle 30 cannot be obtained unless the flow rate introduced into this chamber 26, that is, the pressure p is increased. There will be no. As a result, even in a region where the injection amount is small, sufficient swirling flow rate intensity can be achieved in the swirl chamber 26, and sufficient atomization can be achieved even in this region. Conventionally, such a return piping system was not installed, and the spray amount characteristics from the first swirl chamber 26 at this time were as follows.
As shown in Figure m+. For the same spray volume, for example gl, in the present invention the pressure at the inlet of the swirl chamber is p! , while conventionally p
It is m. As a result, the flow velocity within the swirl chamber 2 fi was lower than in the present invention, which in turn led to worsening of atomization.

Note that the check valves 42, 60 are returned to the closed position by the springs 48, 82 after the fuel supply is stopped. by this,
Fuel is prevented from flowing back and dripping from the nozzle during a stop. The springs 48 and 82 are set to have a suitably weak force so as to perform a similar backflow prevention function, but not to impede the smooth flow of fuel during operation.

In the second embodiment shown in FIGS. 8 and 9, the structure of the fuel injection valve 1 is the same as that in FIGS. 2 and 3. In addition to this, a second flow control device 80 is installed within the pipe 7' corresponding to the return vibe 7 in FIG. The flow rate control device 80 is configured as a valve device that makes the return flow rate in the pipe 7' zero or decreases in a large flow rate region. By setting such a flow rate control device, as shown by the broken line in Fig. 6,
The characteristic I12' in the large flow range is that of the conventional one without restriction (m
z), and in the small flow rate region lI', it can be made equivalent to the characteristic (7!+) of the present invention in which a throttle is installed. The pressure of the pump 4 shown in FIG. 1 can be lowered by not providing relief in the high flow rate range, and the pump power can be reduced.

FIG. 10 shows a fuel injection valve 1' of still another embodiment,
In this case, the difference from the previous embodiment is that only a single swirl chamber 26 is provided. This single swirl chamber is formed by the throttle member 74.
-tA to the return pipe, which maintains the inlet pressure high even in the low injection amount region and improves the atomization characteristics. Further, FIG. 11 shows an embodiment having a single swirl chamber 26, and like the embodiments of FIGS. 8 and 9, it has a device 80 for controlling the return flow rate.

Effects of the invention By returning part of the fuel in the swirl chamber to the return pipe, the inlet pressure can be increased even in a small flow rate region, and the injection area performance in this region can be improved. The applicable flow rate range can be expanded.

Further, since the diameter of the inflow hole to the swirl chamber can be increased, processing becomes easier.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the overall configuration of a device including the fuel injection valve of the present invention. FIG. 2 is a detailed sectional view of the fuel injection valve of FIG. 1.
FIG. 4 is a partially enlarged view of FIG. 1. FIG. 5 is a plan view of the swirl chamber. FIG. 6 is a flow rate characteristic diagram of the fuel injector of the present invention. FIG. 7 shows the state of spray from the nozzle. Explanatory drawings FIGS. 8 and 9 are similar to FIGS. 2 and 3 showing a second embodiment of the present invention. FIGS. 10 and 11 are similar to FIGS. Diagrams similar to FIG. 2 or FIG. 8 showing the fourth embodiment ■, 1'...Fuel injection valve, 7...Return pipe, 26
゜28... Vortex chamber, 30,' 32... Spout, 7
4... Aperture member, 741... Orifice. Patent Applicant Toyota Motor Corporation Patent Application Agent Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Takao Mitsui Patent Attorney Akira Yamaguchi Figure 1 Figure 2 Figure 3 Figure 4 Figure 7 Figure 8

Claims (1)

[Claims] 1. In a fuel injection valve equipped with a swirl chamber, a fuel return passage is opened in the swirl chamber at a position opposite to the nozzle, and a flow rate control throttle is provided in the fuel return passage. A fuel injection valve equipped with a control mechanism. 2. The fuel injection valve according to claim 1, wherein the flow rate control mechanism includes a throttle having a fixed size and a control device for suppressing or reducing the return flow rate through the fixed throttle. 3. The fuel injection valve according to claim 1, wherein the swirl chamber is composed of two large and small swirl chambers, and the fuel return passage is provided in the smaller swirl chamber.