JPH01178763A - Solenoid-controlled fuel injection valve - Google Patents

Abstract

PURPOSE:To improve the atomization capacity of fuel by installing a second fuel diffusion element in the inner part of a first fuel diffusion element installed at the downstream side of a valve seat. CONSTITUTION:Fuel passing through between a valve body 10 and a valve seat 12 flows into an orifice 17 at the time of valve opening of a fuel injection valve 1 and, after fuel metering and swirling force to the fuel are given by this orifice 17, it is sprayed to a ring void 18. The sprayed fuel is atomozed as repeating its collisions with an inner circumferential surface of a first diffusion element 6 and an outer circumferential surface of a second fuel diffusion element 15 while swirling in the ring void 18 and then it is sprayed at a specified spray angle from an outlet 6a of an injection nozzle 6. With the presence of these fuel diffusion elements 6, 15 like this, collision frequency of the fuel is sharply increasable so that a fuel diffusive effect by a series of collisions can be sufficiently brought out and, what is more, atomization capacity of the fuel is improvable owing to a synergetic effect of diffusion and swirling energy by these collisions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electromagnetic fuel injection valve used, for example, in a fuel supply device such as an engine.

[Conventional technology]

Generally, an electromagnetic fuel injection valve opens and closes the valve by reciprocating the valve body by energizing (magnetic attraction) and de-energizing (magnetic attraction release) an electromagnetic coil, and injects fuel when the valve is open. Also,
In such a fuel injection valve, in order to measure and atomize the fuel, it is necessary to install an eccentric or inclined part with respect to the valve shaft on the downstream side of the valve seat, as disclosed in, for example, Japanese Patent Application Laid-Open No. 60-252164. This is done by arranging a swirl orifice. That is, when the valve is opened, the fuel passing through the swirl orifice is metered, and a swirling force is applied to swirl the fuel coming out of the swirl orifice inside the injection nozzle. (inner wall of the nozzle) to disperse the fuel into a film and atomize the fuel.

[Problem to be solved by the invention]

By the way, in the conventional fuel injection method using the swirl orifice as described above, the effect of fuel atomization due to collision occurs only immediately after the fuel leaves the swirl orifice.
The effect of contributing to atomization is much greater from the swirling energy of the fuel dispersed in a film than from collisions.

Therefore, according to the conventional fuel impingement structure, it is technically difficult to achieve further atomization of the fuel in the following cases.

In other words, in recent years, the diameter of the swirl orifice has been reduced due to the increase in the fuel pressure used, the miniaturization of electromagnetic fuel injection valves, and the development of small injection amount injectors. , the pressure drop of the fuel passing through the orifice increases, and the swirling energy and collision energy decrease accordingly. Therefore, in such a case, if no consideration was given, there would be a problem that the fuel atomization performance would deteriorate, which should be improved.

The present invention has been made in view of the above points, and its purpose is to improve the atomization performance of fuel, particularly to increase the fuel pressure used, to reduce the size of electromagnetic fuel injection valves, and to improve the atomization performance of fuel.
An object of the present invention is to provide a fuel injection valve that can achieve good fuel atomization without deteriorating atomization performance even if the diameter of a swirl orifice is reduced due to the use of small injection amount injectors.

[Means to solve the problem]

” Objective 1 will be achieved by adopting the following means: Hereinafter, in order to facilitate understanding of the content of the present invention, the present invention will be described with reference to the reference numerals of the embodiment shown in FIG.

That is, the present invention is an electromagnetic fuel injection valve in which the valve body 10 reciprocates by excitation and de-excitation of the electromagnetic coil 4 to perform a force closing operation. In this device, a swirl orifice 17 and an injection nozzle 6 are disposed to meter the passing fuel and give a swirling force, and a hollow cylindrical first fuel diffusion element 6 is provided on the downstream side of the valve seat 12. A second fuel diffusion element 15 in the form of a cylindrical projection is vertically provided inside the first fuel diffusion element 6 toward the injection nozzle outlet 6a side. An annular gap 18 is formed between the inner and outer circumferential surfaces of the second fuel diffusion elements 6 and 15, and a swirl orifice 17 is formed at the outlet of the annular gap 18.
The fuel ejected from the outlet of the swirl orifice 17 into the annular gap 18 swirls in the annular gap 18 while facing the inner peripheral surface of the first fuel diffusion element 6. and the outer peripheral surface of the second fuel diffusion element 15 so as to repeatedly collide with each other.

[Effect]

According to the present invention having such a configuration, when the fuel injection valve is opened, the fuel passing between the valve body 10 and the valve seat 12 flows into the orifice 17, and the orifice 17 measures and controls the fuel. A turning force is applied to the annular gap 18.
Fuel is injected.

Then, the fuel injected into the annular gap 18 is
While rotating, the particles are atomized while repeatedly colliding with the inner peripheral surface of the first fuel diffusion element 6 and the outer peripheral surface of the second fuel diffusion element 15, and are atomized from the outlet 6a of the injection nozzle 6 at a specified spray angle. Injected. In the present invention, as shown in ``2'' below,
Due to the presence of the second fuel diffusion element 6.15, the number of fuel collisions can be significantly increased compared to the conventional one.
It is possible to fully utilize the fuel diffusion effect caused by collision,
The synergistic effect of the diffusion and swirling energy caused by this collision can improve the atomization performance of the fuel.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal cross-sectional view of an electromagnetic fuel injection valve according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a main part of this embodiment, and FIG. 3 is a view taken along the line A-A in FIG. .

In FIG. 1, reference numeral 1 denotes a bom-feed type electric wire type fuel injection valve, and the main body of the fuel injection valve is a coater 2. core 3
．． Electromagnetic coil 4. Movable body with valve 5. It is composed of an injection nozzle 6 and the like.

The core 3 and the electromagnetic coil 4 are arranged concentrically inside the yoke 2, and a movable body 5 with a valve is located at the lower center of the yoke 2.
A bulb body 13 and an injection nozzle 6 are incorporated.

The movable body 5 with a valve includes a ring 7, a plunger 8. The rod 9 is joined using plastic flow or welded.

The rod 9 is integrated with a ball (
Valve body) 10 is fixed by welding. The entire movable body 5 with a valve is disposed in the fuel passage [1] so as to be able to reciprocate at a predetermined stroke, and its negative end (plunger 8) is biased by a spring 12, and the ball 10 is electromagnetically moved. When the coil 4 is off, it is in pressure contact with the valve seat 12. The valve seat 12 is disposed within the valve body 13, and a hollow cylindrical first fuel diffusion element (in this example,
6, which also serves as a fuel injection nozzle, and a second fuel diffusion element 15 are provided.

Here, prior to the structure 1 action of the fuel diffusion elements 6 and 15,
An overview of the operation of the electromagnetic injection valve 1 will be explained.

The fuel passage system of the injection valve 1 includes the outer circumference of the electromagnetic coil 4 and the H-ri 2.
Fuel passage 1 formed by the outer periphery of the plunger 8 and the inner periphery of the yoke 2;
], the bore portion 12a of the valve seat 12.

It is composed of a swirl orifice 17, which will be described later.

When the on-off signal of the duty calculated and determined by the controller 1 to the roll unit 1 (not shown) is applied to the electromagnetic coil 4 via the connector 20, when current is applied to the electromagnetic coil 4, the core 3 , the yoke 2 and the plunger 8 form a magnetic circuit, and the plunger 8 moves in one direction in the figure. Furthermore, when a magnetic attraction force acts on the plunger 8 upward in the figure, the ring 7 is guided by the inner periphery of the core 3 and slides, and the ball 10 moves away from the valve seat 12 and slides in the bore portion 12a. However, a minute gap is formed between the ball 10 and the valve seat 12, and the valve is in an open state. In this state, fuel supplied from the outer circumference of the yoke 2 through the filter 21 is supplied to the fuel passages 16, 11. It reaches the swirl orifice 17 through the bore part 1.2a, and then, as described later, the amount of fuel power compensation,
The atomized fuel is injected from the injection nozzle port 6a.

The fuel atomization means includes the first fuel diffusion element 6. Second fuel diffusion element ↑5. It is constructed by incorporating the swirl orifice 17 etc. as follows.

Below, we will discuss the fuel atomization means, which is the purpose of improvement in this embodiment, in the second section. This will be explained based on FIG.

In this embodiment, as described above, the first fuel diffusion element 6 also serves as an injection nozzle, has a hollow cylindrical shape, and is attached to the lower end side of the valve body 13. Further, the second fuel diffusion element 15 is formed by providing a flange 15b on a cylindrical projection 1.5a whose outer diameter is somewhat smaller than the inner diameter of the first fuel diffusion element 6. Then, with the flange 1'5b interposed between the lower end surface of the valve seat 12 and the - end surface of the first diffusing element 6, the outer periphery of the cylindrical projection 15a is aligned with the first diffusing element 6. Cylindrical protrusion so as to be concentric with the inner circumference] 5a
is placed vertically toward the inside of the first diffusion element 6. In this way, the first. An annular gap 18 is formed between the inner and outer peripheral surfaces of the second fuel diffusion element 6°15.

Further, a plurality of (six) swirl orifices 17 are arranged in the second fuel diffusion element 15 . The inlet side of these swirl orifices 17 faces one end of the bore 12a of the valve seat 12, and the outlet side faces the annular gap 18, and each orifice 17 is eccentric with respect to the valve axis A as shown in FIG. The angle of inclination is set to be O in this state.

Thus, when the valve is opened, the fuel that has passed through the gap between the ball 10 and the valve seat surface 12' flows into each swirl orifice 17, and the swirl orifice 17 adds a swirling force to the fuel while increasing the amount of fuel by M-1. 1st. The fuel is injected into the annular gap 18 formed between the inner and outer peripheral surfaces of the second fuel diffusion elements 6 and 15. Then, the injected fuel swirls around the annular gap 18 while exhibiting a conical film shape, and in this process, the fuel spreads between the inner circumferential surface of the first fuel diffusion element 6 and the outer circumferential surface of the second fuel diffusion element 15. Pass through repeated collisions. In this process, the fuel repeatedly collides with the diffusion elements 6 and 15, resulting in fine diffusion (atomization), and swirling energy is also applied to the film-like fuel, promoting the atomization of the fuel. The fuel is then injected into an internal combustion engine (not shown) from the nozzle outlet 6a with a conical shape having a prescribed spray angle and a prescribed particle size.

In addition, fuel measurement is performed using multiple swirl orifices 17.
This is done by

FIG. 4 shows the relationship between the angle O of the swirl orifice 17 and the atomized particle size, and the angle θ is uniquely determined by the target spray angle and target particle size. The appropriate number of swirl orifices 17 is 4 to 8 in order to improve swirling and dispersion of the fuel.

FIG. 5 shows the relationship between the cap size δ of the annular gap 18 and the particle size, and FIG. 6 shows the protrusion length Q of the second fuel diffusion element 15.
This is experimental data showing the relationship between particle size and particle size. Therefore, if the gap size δ of the annular gap 18 becomes too small, the fuel will not be able to collide sufficiently, and if it becomes too large, the impact effect will be weakened and the atomization effect will gradually weaken. It is necessary to set δ of 18 to an appropriate value. This gap δ is preferably set within the range of δ1 (δ1 is about 1.5 to 2 times the diameter of the swirl orifice 17) as shown in FIG. Further, the protrusion length Q of the second fuel diffusion element 15 is the angle θ of the swirl orifice 1.
It is necessary to determine Q geometrically so that the fuel injected from 7 collides with the inner periphery of the first fuel diffusion element 6 and the outer periphery of the second fuel diffusion element 15 multiple times and is sprayed. be. As shown in FIG. 6, it is preferable that QICQs is set within the range of a protrusion length that allows the fuel to turn once or twice in the annular gap 18. In addition, the I/F of the fuel after exiting from the swirl orifice 17 until being injected from the nozzle outlet 6a is
- It is preferable to set the number of turns of the barrel to about 3 to 4 times from the viewpoint of atomization.

However, according to this embodiment, since the swirling fuel is repeatedly collided with the inner and outer circumferential surfaces of the first and second fuel diffusion elements 6 and 15, it is possible to significantly increase the number of collisions compared to the conventional method. , fully exploiting the synergistic effect of collision and turning forces,
The atomization performance of fuel can be improved. especially,
According to this embodiment, it is possible to spray small particles on a hollow cone, thereby improving the idle stability of the internal wax engine and the response during acceleration. Furthermore, it is possible to provide an electromagnetic fuel injection valve that does not worsen the degree of atomization even when the orifice diameter is reduced due to the increase in fuel pressure used, the miniaturization of electromagnetic injection valves, and the increase in the injection amount of fuel vehicles. can.

Furthermore, since the swirl orifice 17 is provided at a position deeper than the tip of the nozzle 16, the injector 1 is not connected to the internal combustion engine.
Even when equipped with a fuel cell, it can be an advantageous structure that avoids the adhesion of carbon compounds in the combustion gas and fuel generated during use. Furthermore, since the swirl orifice 17 is formed in multiple pieces, the deterioration in fuel metering accuracy due to adhesion of carbon compounds to each swirl orifice is minor compared to an injection valve that measures fuel with a single orifice. has advantages.

〔Effect of the invention〕

As described above, according to the present invention, the number of collisions for atomizing the injected fuel can be increased, so that the atomization of the fuel can be further improved, and in particular, the pressure of the fuel used can be increased, the size of the fuel injection valve can be reduced, Even when the injection amount of fuel is reduced, the degree of atomization is not deteriorated, and good atomization can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing one embodiment of the present invention, Fig. 2 is a sectional view of the main part of the above embodiment, Fig. 3 is a sectional view taken along line A-A in Fig. 2, and Fig. 4 is a view of the swirl orifice. A diagram showing the relationship between the angle and the particle size of the fuel atomization, Figure 5 is a diagram showing the relationship between the annular gap and the particle size of the fuel atomization, and Figure 6 shows the relationship between the protrusion length of the second fuel diffusion element and the fuel atomization. FIG. 3 is a diagram showing the relationship between grain size and 1... Fuel injection valve, 4... Electromagnetic coil, 6... First fuel diffusion element (injection nozzle), 10... Valve body (ball)
, 12... Valve seat, 15... Second fuel diffusion element, 1
7. Swirl orifice, 18. Annular void.

Claims (3)

[Claims] 1. An electromagnetic fuel injection valve in which a valve body reciprocates to open and close the valve by energizing and de-energizing an electromagnetic coil,
A swirl orifice and an injection nozzle are arranged on the downstream side of the valve seat to measure the fuel passing through the valve and apply a swirling force when the valve is opened. A diffusion element is provided, and a second fuel diffusion element in the form of a cylindrical projection is vertically disposed inside the first fuel diffusion element toward the outlet side of the injection nozzle. An annular gap is formed between the inner and outer circumferential surfaces of the diffusion element, and the swirl orifice is disposed in the second fuel diffusion element with an outlet thereof facing the annular gap, and an outlet of the swirl orifice is provided. The fuel ejected into the annular gap from the annular gap is configured so that it repeatedly collides with the inner circumferential surface of the first fuel diffusion element and the outer circumferential surface of the second fuel diffusion element while rotating in the annular gap. An electromagnetic fuel injection valve featuring: 2. The electromagnetic fuel injection valve according to claim 1, wherein a plurality of the swirl orifices are arranged in the second fuel diffusion element. 3. The electromagnetic fuel injection valve according to claim 1 or 2, wherein the first fuel diffusion element also serves as the fuel injection nozzle.