JP2015169106A - Fuel injection valve, fuel spray generation device including the same, and direct-injection engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve controlling the shape of an overall fuel spray including a plurality of fuel sprays using an axis-switching phenomenon, and achieving the atomization of the fuel sprays and the improvement in the degree of freedom for design of an injection direction, a penetration force, and an injection amount distribution, a fuel spray generation device including the same, and a direct-injection engine.SOLUTION: A switching fuel spray 5A generated by switching injection holes 392 belonging to injection hole groups 393, after going through an axis-switching phenomenon, is controlled to be proximate to or gathered with a fuel spray generated by other injection holes 39 belonging to the same injection groups 393 as those of the switching injection holes 392 by the Coanda effect. As a result, a fuel spray shape of each fuel spray group produced by each injection hole group 393 and an overall fuel spray shape are controlled.

Description

  The present invention relates to a fluid injection valve that injects fluid from a plurality of nozzle holes to generate a spray, a spray generation device including the fluid injection valve, and a direct injection engine (hereinafter referred to as a fuel injection valve) that injects fuel into a combustion chamber. Direct injection engine).

  In recent years, in vehicle engines, research and development for reducing exhaust gas when the engine is cold due to atomization of fuel spray and improving fuel efficiency by improving combustibility have been actively promoted. In particular, research and development of a stratified combustion concept in a spark ignition direct injection engine equipped with a multi-hole injector that directly injects fuel into a combustion chamber is known.

  The fuel spray in such an engine is composed of a spray directed to the vicinity of the spark plug and a spray not directed to the vicinity of the spark plug. The former realizes stratified combustion particularly near the spark plug, and the latter is stratified combustion. It has the role of realizing the mixture formation in the entire combustion chamber in homogeneous combustion.

  When a spark plug is mounted at the center of the combustion chamber and a multi-hole injector as a fuel injection valve is mounted across the intake valve, the spark plug and the multi-hole injector are not opposed. For this reason, the spray specifications required for the spray directed to the vicinity of the spark plug and the spray not directed to the vicinity of the spark plug are different. In other words, the required spray specifications differ between when stratified combustion is performed at a low speed and low load of the engine and when homogeneous combustion is performed at a high speed and high load. Further, if the shape of the combustion chamber, the in-cylinder air flow, the injector mounting position and direction are different, the required specifications for each spray, including the number of sprays of the multi-hole injector, will be different.

  On the other hand, in the atomization process of spraying, in order to reduce the size of the droplets, it is effective to make the liquid yarn, which is the previous stage of the division, thin. In order to make the liquid yarn thinner, it is effective to make the liquid film, which is the previous stage of the splitting of the liquid yarn, thinner or thinner, and the liquid film is more advantageous than the liquid column. I know that. Further, as a liquid film flow forming method, a method is known in which a swirl flow is given to the fuel flow before flowing into the nozzle hole to form a liquid film flow in the nozzle hole.

  The inventor of the present application investigated and examined the relationship between these liquid film flow formation methods and atomization processes, and the spray shape, penetration force, and injection amount distribution of the collective spray in which a plurality of single sprays gathered based on these techniques. As a result, it has been found that the collective spray in which single sprays are gathered can be divided into the following two forms.

  One is a case where each single spray is identifiable and the characteristics of each single spray become a collective spray that is almost indistinguishable. This is a collective spray with a solid structure that is relatively homogeneous, and each single spray can be identified, but it has the same characteristics as the collective spray, and is a spray that is difficult to control halfway. is there.

  The other is the case of a collective spray that makes it impossible to identify each single spray. This is a collective spray whose representative example is an injection amount distribution having a conical shape with a central peak, and a plurality of single sprays are gathered and replaced with a single new collective spray that is almost different from the original form, It is a very characteristic and stable phenomenon.

  Which of these forms depends largely on whether the spray behavior is at a certain threshold. The more the single spray is assembled, the closer the spray amount distribution is to axial symmetry and the sharper cone shape, so that the penetration force as a whole spray increases. In either case of the above two forms, a plurality of single sprays gather, and in the collective spray in which the spray shape in the plane perpendicular to the spray direction and the spray amount distribution are substantially axisymmetric, the cross-sectional shape is It is difficult to make a non-target variant and direct a part of the spray in a desired direction.

  Although the atomization technique as described above is being applied to the fuel injection valve, the mainstream of the atomization technique is the small injection hole diameter and multiple injection holes, and the jets from adjacent injection holes interfere with each other. It is designed so that the atomization state does not deteriorate. In other words, the nozzle hole specifications such as nozzle hole arrangement, nozzle hole diameter, inclination, and length are set so that the nozzle hole center axis or the jet flow direction becomes more downstream. Are difficult to balance.

  As a technique for suppressing the spread of the entire spray, it is known that the nozzle hole arrangement and the nozzle hole specifications are such that the nozzle hole central axis or the jet direction intersects each other immediately below the nozzle hole. However, in this method, the relationship from the outlet of the nozzle hole to the position where the liquid film flow can be regarded substantially as a spray flow after breaking or splitting the liquid film flow (breaking length of the liquid film flow) and the atomization Requirements were not considered.

  On the other hand, in order to suppress the spread of the entire spray, it is disadvantageous to form a thin liquid film flow if the angle of the injection hole central axis relative to the plane perpendicular to the operation central axis of the fluid injection valve is relatively small. That is, the atomization process becomes slow and the jets easily interfere with each other, and the atomization level cannot be achieved as expected. In addition, as described above, when the collective spray of a plurality of single sprays is generated due to the interference between the jets, the penetration force is greater than that in the single spray.

  Furthermore, in order to reduce spray collisions on the cylinder liner and promote mixing with air, a method of rapidly attenuating the spray penetration force at a predetermined distance is desired, but there is no method to achieve without significantly changing the spray form. It was. For this reason, in order for each spray to attenuate the penetration force rapidly, it is necessary to accelerate the attenuation of the spray momentum by a method such as flattening the jet flow from the nozzle hole outlet. In order to avoid interference between the jets, it was necessary to further separate the jet directions.

  For example, in a spark ignition direct injection engine, as a prior art aiming at ensuring both spray penetration force and appropriate dispersion of spray density, Patent Document 1 discloses that the main injection hole and the injection center are the main injection holes. It has a secondary injection hole that points in a different direction from the injection center, and is set so that the cross-sectional area of the inlet and outlet of the main injection hole is different. A multi-hole injector with distributed density is presented.

  Further, in Patent Document 2, cavitation bubbles are generated in the first taper portion that contracts in the fuel flow direction in the nozzle hole, and the generated cavitation bubbles collapse to atomize the fuel and atomize the fuel. A fuel injection valve is proposed in which the penetration force is reduced by diffusing by a second taper portion that expands in the flow direction.

  On the other hand, in fluid engineering, an axis-switching phenomenon is known in which the direction of the major axis and the minor axis of a switching spray having an oval cross-sectional shape ejected from an injection hole changes downstream. (Nonpatent literature 1-6). This axis-switching phenomenon does not have to be oval in the cross-sectional shape of the spray, and is established as long as the major axis is substantially line-symmetric with respect to the minor axis.

JP 2007-315276 A JP 2012-14504 A

Proceedings of the Japan Society of Mechanical Engineers (Part B), Vol. ILASS-Europe 2010, “An experimental investigation of discharge coefficient and cavitation length in the elliptical nozzles” (Sung Ryoul Kim) Production Research Volume 50 No. 1, pp 69-72, “Numerical Simulation of Complex Turbulent Jets: Origin of Axis-Switching” (Ayodeji O. DEMUREN) Jet Engineering, Morikita Publishing, pp41-42 Proceedings of the Japan Society of Mechanical Engineers (Part 2) Vol. 25, No. 156, pp 820-826, "Study on the reach of diesel engine fuel spray" (Waguri et al.) Proceedings of the Japan Society of Mechanical Engineers (Part B) Vol. 62, No. 599, pp2867-2873 “Effect of Atmospheric Viscosity on Diesel Spray Structure”

  As described above, in the prior art, in a spark ignition direct injection engine equipped with a multi-hole injector, it is required for each of the spray directed to the vicinity of the spark plug and the spray diffused throughout without directing the vicinity of the spark plug. The degree of freedom of design for realizing the spray specification was low, and it could not be realized sufficiently. In particular, atomization of spray, spray shape, and penetration force are characteristics that have a correlation with each other. However, Patent Document 1 and Patent Document 2 do not consider the influence of them, and thus realize an optimal spray specification. It is not possible.

  In a nozzle like patent document 1, it is known that the way of inflow of fuel to each nozzle hole will actually change with the way of flow inside a sac (cavity) upstream of a nozzle hole. That is, when the cross-sectional areas of the injection hole inlet and the outlet are made different, it is not always possible to widen the spray angle while keeping the injection amount constant. In particular, when a plurality of injection holes are not arranged symmetrically with respect to the central axis of the injector, the flow patterns in the injection holes are often not the same, but Patent Document 1 does not consider these.

  In Patent Document 2, since the influence on the cavitation due to the fuel pressure and the peeling state is not shown, the level of atomization is unknown. If the level of atomization is different, the momentum of the entire spray is different and affects the penetration. In particular, as spray directed to the vicinity of the spark plug, a method for more reliably improving the degree of freedom in design such as spray shape and penetration force is desired.

  In order to solve the problems of Patent Document 1 and Patent Document 2, in the prior application (Japanese Patent Application No. 2013-214336) by the present inventor, at least one of a plurality of nozzle holes arranged in the nozzle hole body of the fluid injection valve. Has been proposed to be a switching nozzle hole that generates switching spray. According to this, in the combustion chamber of the spark ignition direct injection engine, the cross-sectional shape in a plane perpendicular to the spray direction of the spray is changed by using the axis-switching phenomenon, and the spray directed to the vicinity of the spark plug is generated. be able to.

  However, in this prior application, only the spray direction of a part of the entire spray is controlled using the axis-switching phenomenon, and depending on various combustion chamber shapes, in-cylinder air flow, injector mounting positions, etc. In order to form an overall spray suitable for mixture formation or combustion, there is room for further improvement.

  The present invention has been made in order to solve the above-described problems, and controls the shape of the entire spray including a plurality of sprays by using the switching spray generated by the switching nozzle holes, and spray fine particles. It is an object of the present invention to provide a fluid injection valve and a spray generation device including the fluid injection valve, which are compatible with the improvement of spraying direction, penetrating force, and improvement in the degree of freedom in design of the injection amount distribution.

  In addition, a spray shape suitable for gas mixture formation or combustion is realized using switching spray generated by the switching nozzle hole, and the atomization of the spray, the spray direction, penetration force, and the degree of freedom in design of the injection amount distribution are realized. An object is to obtain a direct injection engine that achieves both improvement.

  A fluid injection valve according to the present invention includes a valve seat provided in the middle of a passage through which a fluid flows, a valve body that can contact and separate from the valve seat and controls opening and closing of the passage, and a downstream of the valve seat. A fluid injection valve that injects fluid from a plurality of nozzle hole groups arranged in the nozzle hole body to generate a plurality of spray groups, each of the plurality of nozzle hole groups being mutually A plurality of nozzle holes arranged in proximity to each other, and at least one of the plurality of nozzle hole groups is a switching spray in which the major axis and the minor axis have different lengths in a cross-sectional shape in a plane perpendicular to the fluid ejection direction. The switching spray generated by the switching nozzle including at least one switching nozzle to be generated changes the direction of the major axis and the minor axis at a predetermined distance from the switching nozzle, and after the change has occurred, By another nozzle hole belonging to the same nozzle hole group as the switching nozzle hole Between the spray produced, in which the proximity of or aggregation due to the Coanda effect is controlled to occur.

  Moreover, the spray production | generation apparatus which concerns on this invention is equipped with said fluid injection valve, the fluid supply means which supplies a fluid to a fluid injection valve, and the control means which controls operation | movement of a fluid injection valve.

  A direct injection engine according to the present invention is a direct injection engine provided with a fuel injection valve for injecting fuel into a combustion chamber, and the fuel injection valve is a valve seat provided in the middle of a passage through which fuel flows. A plurality of injection holes disposed in the injection hole body, and a valve body that is provided so as to be capable of contacting and separating from the valve seat and that controls opening and closing of the passage, and an injection hole body provided downstream of the valve seat The fuel is injected from the group to generate a plurality of spray groups, each of the plurality of nozzle hole groups has a plurality of nozzle holes arranged close to each other, and at least one of the plurality of nozzle hole groups Includes at least one switching nozzle for generating a switching spray having a major axis and a minor axis having different cross-sectional shapes in a plane perpendicular to the fuel injection direction, and the switching spray generated by the switching nozzle is Long axis and short axis at a predetermined distance from the switching nozzle The direction is changed, and after the change occurs, control is performed so that the Coanda effect causes proximity or aggregation between the switching nozzle and the spray generated by another nozzle belonging to the same nozzle hole group. It is what is done.

  According to the fluid injection valve and the spray generating device including the same according to the present invention, the switching spray generated by the switching nozzle hole belonging to the nozzle hole group is changed in the direction of the major axis and the minor axis, Each switching hole and each spray hole generated by another nozzle hole belonging to the same nozzle hole group are controlled so as to cause proximity or aggregation due to the Coanda effect. It becomes possible to control the spray shape of the spray group and the overall spray shape, and it is possible to achieve both atomization of the spray and improvement in the degree of design freedom of the spray direction, penetration force, and spray amount distribution.

  Further, according to the direct injection engine according to the present invention, the switching spray generated by the switching nozzle holes belonging to the nozzle hole group is the same as the switching nozzle holes after a change in the direction of the major axis and the minor axis occurs. Spray shape of each spray group generated by each nozzle hole group by being controlled to cause proximity or aggregation due to the Coanda effect between the sprays generated by another nozzle hole belonging to the nozzle hole group It is possible to control the overall spray shape to a shape suitable for mixture formation or combustion in the combustion chamber, and to improve atomization of the spray and the degree of freedom in designing the spray direction, penetration force, and injection amount distribution It is possible to achieve both.

It is sectional drawing which shows the fuel injection valve which concerns on Embodiment 1 of this invention. It is an expanded sectional view which shows the front-end | tip part of the fuel injection valve which concerns on Embodiment 1 of this invention. It is a top view which shows the example of arrangement | positioning of the nozzle hole in the nozzle hole plate of the fuel injection valve which concerns on Embodiment 1 of this invention. It is a detailed sectional view explaining the structure of the tip part of the fuel injection valve concerning Embodiment 1 of the present invention. It is a detailed sectional view explaining the structure of the tip part of the fuel injection valve concerning Embodiment 1 of the present invention. It is a figure explaining the behavior until two non-switching sprays form a collective spray by the Coanda effect as a reference example. It is a figure explaining the behavior until two non-switching sprays form a collective spray by the Coanda effect as a reference example. It is a figure explaining the behavior when the Coanda effect does not act on two non-switching sprays as a reference example. It is a figure explaining the behavior of the non-switching spray and switching spray which are produced | generated by two nozzle holes which belong to the same nozzle hole group and adjoin each other in the fuel injection valve which concerns on Embodiment 1 of this invention. It is a top view which shows the other example of arrangement | positioning of the nozzle hole in the nozzle hole plate of the fuel injection valve which concerns on Embodiment 1 of this invention. In the fuel injection valve which concerns on Embodiment 1 of this invention, it is a figure explaining the behavior of the non-switching spray and switching spray which are produced | generated by two nozzle holes which belong to another nozzle hole group, and mutually adjoin. In the fuel injection valve which concerns on Embodiment 1 of this invention, it is a figure explaining the behavior of the non-switching spray and switching spray which are produced | generated by two nozzle holes which belong to another nozzle hole group, and mutually adjoin. It is a figure explaining the example of the whole spray formed in the fuel injection valve which concerns on Embodiment 1 of this invention. It is a figure which shows in time series until each spray group reaches the whole spray in the fuel injection valve which concerns on Embodiment 1 of this invention. It is a figure explaining the spark ignition type direct injection engine which concerns on Embodiment 2 of this invention. It is a figure explaining the compression ignition type direct injection engine which concerns on Embodiment 3 of this invention.

Embodiment 1 FIG.
Hereinafter, a fluid injection valve and a spray generation device according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a fuel injection valve according to the first embodiment, and FIG. 2 is an enlarged cross-sectional view showing a tip portion of the fuel injection valve according to the first embodiment. In the drawing, the same and corresponding parts are denoted by the same reference numerals.

  The spray generation device according to the first embodiment controls the operation of the fuel injection valve 1 that is a fluid injection valve, fuel supply means (not shown) that supplies fuel to the fuel injection valve 1, and the fuel injection valve 1. And a control device (not shown) as control means. In the following description, the fuel injection valve 1 that is attached to the cylinder head of the engine and is arranged so that the tip portion for injecting fuel faces the cylinder of the engine will be described as an example.

  The fuel injection valve 1 includes a solenoid device 2 that generates electromagnetic force, and a valve device 3 that operates by energizing the solenoid device 2. The solenoid device 2 includes a housing 21 that forms a yoke portion of a magnetic circuit, a core 22 that is a fixed iron core provided inside the housing 21, a coil 23 provided so as to surround the core 22, and an inner side of the coil 23. Is provided with an armature 24 that is a movable iron core that reciprocates.

  The valve device 3 includes a valve body 31 that is cylindrical and press-fitted and welded to the outer diameter portion of the distal end portion of the core 22, and a valve seat 32 that is provided in the passage of fuel inside the valve body 31. I have. Downstream of the valve seat 32, an injection hole plate 33, which is an injection hole body having a plurality of injection holes 39 for injecting fuel, and a cover plate 34 provided upstream of the injection hole plate 33 inside the valve seat 32. The valve body 35 is provided inside the valve body 31 so as to be capable of contacting and separating from the valve seat 32 and controls the opening and closing of the passage, and a compression spring 36 provided upstream of the valve body 35.

  The valve body 35 includes a hollow rod 37 that is press-fitted and welded to the inner surface of the armature 24, and a ball 38 that is fixed to the tip of the rod 37 by welding. As shown in FIG. 2, the ball 38 includes a chamfered portion 38 a parallel to the Z axis (indicated by an arrow in FIG. 1) of the fuel injection valve 1, a flat portion 38 b facing the cover plate 34, and a valve seat 32. And a curved surface portion 38c that comes into line contact.

  The nozzle hole plate 33 has a peripheral edge bent downward and is welded to the distal end surface of the valve seat 32 and the inner peripheral side surface of the valve main body 31. A nozzle hole 39 penetrating in the thickness direction is formed in the nozzle hole plate 33. The nozzle hole 39 is a general term for a non-switching nozzle hole 391 and a switching nozzle hole 392 described below, and is used when it is not necessary to distinguish between them.

  FIG. 3 is a plan view showing an arrangement example of the injection holes 39 in the injection hole plate 33 of the fuel injection valve 1 according to the first embodiment. The nozzle hole 39 includes a non-switching nozzle hole 391 having a substantially circular cross-sectional shape perpendicular to the nozzle hole axis 33, that is, a cross-sectional shape perpendicular to the nozzle hole axis, and a cross-sectional shape perpendicular to the nozzle hole axis having a major axis and a minor axis. For example, there are two types, an oval switching nozzle hole 392. The nozzle hole plate 33 may be formed integrally with the valve seat 32. In this case, the switching nozzle hole 392 has a cross-sectional shape perpendicular to the nozzle hole axis corresponding to the fluid injection direction as the major axis. The shape has a short axis.

  As shown in FIG. 3, the nozzle hole plate 33 includes four nozzle hole groups 393a, 393b, 393c, and 393d (collectively, the nozzle hole group 393), and one switching hole 392e provided independently. Is arranged. Each of the plurality of nozzle hole groups 393 has a plurality of nozzle holes 39 arranged close to each other, and at least one of the plurality of nozzle hole groups 393 includes at least one switching nozzle hole 392.

  In the example shown in FIG. 3, the nozzle hole group 393a has a non-switching nozzle hole 391a and a switching nozzle hole 392a, and the nozzle hole group 393b has a non-switching nozzle hole 391b and a switching nozzle hole 392b. Similarly, the nozzle hole group 393c has a non-switching nozzle hole 391c and a switching nozzle hole 392c, and the nozzle hole group 393d has a non-switching nozzle hole 391d and a switching nozzle hole 392d. In each nozzle hole group 393, the long axis of the switching nozzle hole 392 is arranged to face the non-switching nozzle holes 391 included in the same nozzle hole group 393.

  When the jet of fuel injected from the non-switching nozzle 391 proceeds downstream by a predetermined distance (break length), a non-switching spray having a substantially circular cross-sectional shape in a plane perpendicular to the injection direction is generated. Further, when the jet flow ejected from the switching nozzle 392 proceeds downstream by a predetermined distance (break length), the switching spray in which the major axis and the minor axis have different lengths in a cross-sectional shape perpendicular to the ejection direction is generated. Generate.

  The switching spray generated by the switching nozzle hole 392 is controlled to cause an axis-switching phenomenon at a predetermined distance from the switching nozzle hole 392, and changes the direction of the major axis and the minor axis. The behavior of each spray will be described later in detail.

  Next, the operation of the fuel injection valve 1 will be described. When an operation signal is sent from the engine control device to the drive circuit of the fuel injection valve 1, a current is passed through the coil 23 of the fuel injection valve 1, and the armature 24 is attracted to the core 22 side. As a result, the rod 37 and the ball 38, which are integral with the armature 24, move upward against the elastic force of the compression spring 36, the curved surface portion 38c of the ball 38 is separated from the valve seat surface 32a, and there is a gap between them. Is formed to form a passage, and fuel injection directed to the intake port is started.

  On the other hand, when an operation stop signal is sent from the engine control device to the drive circuit of the fuel injection valve 1, the energization to the coil 23 is stopped, and the force with which the armature 24 is attracted to the core 22 side disappears, and the rod 37 Is pushed toward the valve seat 32 by the elastic force of the compression spring 36, the curved surface portion 38c of the ball 38 and the valve seat surface 32a are closed, and fuel injection is terminated at this point.

  Here, the detailed structure and position of the nozzle hole plate 33, the cover plate 34, the valve seat 32, and the ball 38 in which the flow in the nozzle hole 39 is converted into a liquid film flow by, for example, contraction flow are shown in FIGS. 5 will be described with reference to the detailed sectional views of FIG. The nozzle hole 39 described here may be either a non-switching nozzle hole 391 or a switching nozzle hole 392. In FIG. 4, X indicates the diameter of the nozzle hole 39, and Y indicates the length of the nozzle hole 39.

  When the valve element 35 is opened, the fuel passes through a path parallel to the Z-axis between the chamfered portion 38a of the ball 38 and the inner surface of the valve seat 32, and then between the curved surface portion 38c of the ball 38 and the valve seat surface 32a. To the downstream and reach the valve seat portion R1. Since the fuel flows parallel to the Z-axis upstream of the valve seat portion R1, the flow of the fuel is mainly along the valve seat surface 32a due to inertia after passing through the valve seat portion R1. The point P1 at the downstream end is reached.

  The point P1 is the end of the valve seat surface 32a, and the valve seat 32 has a surface extending in the vertical direction downstream from the point P1. Therefore, the main flow of fuel is separated from the point P1. The extension line of the valve seat surface 32a intersects the peripheral side surface of the cover plate 34 at the point P2, and the fuel separated from the point P1 faces the point P2, and the annular passage C (the inner peripheral wall surface of the valve seat 32 and the cover plate 34). Between the large-diameter portion 34d) and the radial passage B (the inner peripheral wall surface of the valve seat 32 and the periphery of the small-diameter portion 34c of the cover plate 34) without significant change in the radial direction. Between the sides).

  In addition, since the main flow of the fuel that passes through the valve seat portion R1 flows into the annular passage C, the flow into the clearance passage A (between the bottom surface of the ball 38 and the top surface 34a of the cover plate 34) is suppressed. . A line connecting the sheet portion R1 and the point P3 at the entrance of the injection hole 39 with a straight line intersects with a thin portion 34b which is a large diameter portion of the cover plate 34. That is, the thin portion 34b blocks the linear flow of fuel from the valve seat portion R1 to the inlet of the injection hole 39.

  For this reason, at least a part of the fuel flowing into the nozzle hole 39 flows along the radial passage B. The cover plate 34 has a small diameter portion 34 c disposed closer to the nozzle hole 39 on the inner diameter side than the nozzle hole 39. Accordingly, the front flow F1 of the fuel directed toward the inner diameter side along the radial passage B closes the flow path of the return flow F2 flowing into the injection hole 39 from the Z axis of the fuel injection valve 1, and the speed of the return flow F2 is increased. Reduce. By suppressing the return flow F2, the speed of the front flow F1 flowing into the nozzle hole 39 from the valve seat portion R1 side is relatively increased.

  Because at least a portion of the front flow F1 travels along the radial passage B and is forced to undergo a significant change in direction in the nozzle hole 39, and because the front flow F1 is high speed, the fuel is injected into the nozzle hole. In the cross section 39, the fuel injection valve 1 is strongly pressed against the wall surface of the injection hole 39 on the Z-axis side. Thereafter, as shown in FIG. 5, at the inlet of the nozzle hole 39, the low-speed return flow F2 forms a flow F3 along the wall surface of the nozzle hole 39, and the high-speed front flow F1 is a fuel that presses the fuel against the wall surface. Stream F4 is formed.

  In addition, the air flow F5 introduced from the outlet of the nozzle hole 39 acts on the fuel flow F4, and the fuel flow F4 is separated from the point P4 (the outer edge of the fuel inlet of the nozzle hole 39). . The fuel flow F4 is pressed against the wall surface as it travels through the nozzle hole 39, and the direction of the liquid film changes in the direction along the wall surface of the nozzle hole 39 while spreading in the circumferential direction of the wall surface of the nozzle hole 39. .

  As described above, the thinner the liquid film, the thinner the liquid thread and the more effective the atomization of the droplets. Therefore, in the first embodiment, the nozzle hole 39 has a height h (see FIG. 4) of the gap passage A. The length Y is optimized so that the fuel flow F4 is pressed into the thin liquid film flow 30 in the nozzle hole 39. As a result, the liquid film flow 30 of the injected fuel starts to split after a predetermined distance, and droplets atomized through the state of the liquid yarn are generated.

  Next, in the fuel injection valve 1 according to the first embodiment, a method for controlling the spray shape, the penetration force, the injection amount distribution, and the spray direction using the axis-switching phenomenon will be described. First, as a reference example, basic spray behavior will be described with reference to FIGS. FIG. 6 is a diagram for explaining the behavior until the Coanda effect acts on two non-switching sprays to form a collective spray. Note that the Coanda effect is an effect that induces the proximity of adjacent sprays.

  In FIG. 6, (a) is a side view showing non-switching spray injected from two non-switching nozzle holes, and (b) is EE, FF, GG, HH in (a). It is sectional drawing in the part shown by. As shown to Fig.6 (a), the jets 4a and 4b injected from the two non-switching nozzle holes 391 arrange | positioned by the space | interval L1 become the non-switching sprays 4A and 4B, respectively. The jets 4a and 4b have a jet cross-sectional shape shown in a cross-section EE when a break in a state in which the liquid film flow can be regarded as a spray flow after breaking or splitting occurs.

  The distance between the non-switching nozzle hole 391 and the cross section EE at this time is defined as a break length a. Already at the position of the break length a, the gap c1 between the jets 4a and 4b is smaller than the threshold value at which the Coanda effect acts. Subsequently, in the cross-section FF, the jets 4a and 4b are dispersed to become a single non-switching spray 4A and 4B, and the two non-switching sprays 4A and 4B are located at a distance b from the non-switching nozzle hole 391. , Its outer diameter begins to touch.

  Further, from the cross-section FF, the Coanda effect acts between the two single non-switching sprays 4A, 4B due to the pressure distribution, and the single non-switching spray 4A, 4B approaches the cross-section G- Aggregation proceeds like G. At the same time, entrainment of the ambient air of the non-switching sprays 4A and 4B, and thereby induction of an air flow along the flow direction downstream of the substantially central portion in the non-switching sprays 4A and 4B.

  Note that even if the jet 4a and the jet 4b, or the non-switching spray 4A and the non-switching spray 4B have characteristics that cause an axis-switching phenomenon, before the axis-switching phenomenon occurs, the cross-section E- At the position E, the gap c1 between the jets 4a and 4b is smaller than the threshold value at which the Coanda effect acts, so the Coanda effect begins to act and approaches.

  Here, the entrainment level of the ambient air is not a level that greatly changes the shape of the entire collective spray 40 in which the single non-switching sprays 4A and 4B are assembled. Further, if the conditions are adjusted, the assembly further proceeds from the state of the collective spray 40 having the cross section GG, and is substantially regarded as one solid collective spray 40 like the cross section HH.

  FIG. 7 is a diagram illustrating the behavior of the two non-switching sprays until they form a collective spray due to the Coanda effect, with arrows indicating the entrainment status of the surrounding air, and (a) shows the injection from the two non-switching nozzle holes. The side view which shows the made non-switching spray, (b) is sectional drawing in the part shown by FF, G1-G1, G2-G2, HH in (a).

  As shown to Fig.7 (a), the airflow V along the flow direction downstream is induced in spray by the entrainment of ambient air. As a result, as shown in FIG. 7B, the spray amount distribution of each spray in FF, G1-G1, G2-G2, and HH has a peak at the approximate center of the collective spray 40.

  As described above, when the plurality of non-switching sprays 4A and 4B form the collective spray 40 by the action of the Coanda effect, the air flow along the downstream flow direction is induced in the spray by the entrainment of the ambient air, and the penetration force It becomes difficult to suppress the spraying, and the degree of freedom in design is reduced with respect to atomization of the spray and the spray shape.

  Moreover, FIG. 8 is a figure explaining the behavior until the Coanda effect does not act on two non-switching sprays and forms independent sprays. In FIG. 8, (a) is a side view of non-switching spray injected from two non-switching nozzle holes, and (b) is a cross section at a portion indicated by EE, FF, and GG in (a). FIG. As shown to Fig.8 (a), the jets 4a and 4c injected from the two non-switching injection holes 391 arrange | positioned by the space | interval L2 (L2> L1) become the non-switching sprays 4A and 4C, respectively.

  The jets 4a and 4c have a jet cross-sectional shape in a cross-section EE when a break in a state in which the liquid film flow can be regarded as a spray flow after breaking or splitting occurs. At the position of the break length a at this time, the gap between the jets 4a and 4c is larger than the threshold value at which the Coanda effect acts. Further, the gap c2 between the sprays 4A and 4C in the cross section GG is also larger than the threshold value at which the Coanda effect acts, and the Coanda effect does not act on the sprays 4A and 4C. As a result, both the sprays 4A and 4C proceed in the initial traveling direction while remaining independent.

  In FIG. 8, the two non-switching nozzle holes 391 are described as an example. However, even if the combination of the non-switching nozzle holes 391 and the switching nozzle holes 392 is used, the Coanda effect does not act between the two sprays. It is possible to design each to form an independent spray.

  In the first embodiment, the plurality of nozzle holes 39 included in one nozzle hole group 393 is close to the adjacent sprays until at least the switching spray generated by the switching nozzle holes 392 causes an axis-switching phenomenon. The coanda effect that induces the formation is arranged at intervals at which they do not interact with each other, and the nozzle hole specifications including the nozzle hole diameter, length, and inclination are set.

  Further, each spray generated by the plurality of nozzle holes 39 included in one nozzle hole group 393 is in contact with the adjacent spray at least until the switching spray generated by the switching nozzle holes 392 causes an axis-switching phenomenon. The flow rate, the particle size, and the particle number density are set so that the Coanda effect for inducing proximity does not act on each other.

  Further, the switching nozzle hole 392 has a nozzle hole diameter, a length, and an inclination so as to generate a switching spray whose major axis is substantially line symmetric with respect to the minor axis in a cross-sectional shape in a plane perpendicular to the injection direction. The injection hole specifications to be included are set. Further, in the first embodiment, the nozzle hole specifications of the switching nozzle hole 392 are set so as to generate switching spray that changes the direction of the major axis and the minor axis by approximately 90 degrees due to the axis-switching phenomenon.

  That is, in the fuel injection valve 1 according to the first embodiment, the adjacent sprays are deformed close to each other by the action of the Coanda effect only after at least one of them is a switching spray and an axis-switching phenomenon occurs. It is. In this case, by bringing two or more sprays close to each other, a non-circular collective spray having an asymmetric cross-sectional shape in a plane perpendicular to the injection direction is formed.

  Next, in the nozzle hole plate 33 (see FIG. 3) of the fuel injection valve 1 according to the first embodiment, the nozzle holes 391a and the switching nozzle holes 392a that belong to the same nozzle hole group 393a and are adjacent to each other are generated. The behavior until the non-switching spray 4A and the switching spray 5A form the collective spray 50 due to the Coanda effect will be described with reference to FIG. 9, (a) is a side view of each spray, and (b) is a cross-sectional view at a portion indicated by EE, FF,..., MM in (a).

  As shown in FIG. 9A, the non-switching nozzle hole 391a and the switching nozzle hole 392a are arranged at an interval L3. The jet 4a injected from the non-switching nozzle hole 391a becomes the non-switching spray 4A, and the jet 5a injected from the switching nozzle 392a becomes the switching spray 5A. In FIG. 9, assuming that the break lengths a of the jet 4a and the jet 5a are substantially equal, the cross-sectional shape of the jet at this time is as shown in the section EE.

  The switching spray 5A having an oval cross-sectional shape is opposed to the non-switching spray 4A in the major axis direction before the axis-switching phenomenon occurs. The switching spray 5 </ b> A faces the non-switching spray 4 </ b> A and flows downstream while maintaining the initial flow direction almost directly below the switching nozzle hole 392 while its cross-sectional shape slightly expands in both the major axis and minor axis directions. .

  After that, an axis-switching phenomenon occurs at a predetermined distance from the switching nozzle hole 392, and the major axis and minor axis directions of the switching spray 5A start to change as shown in the section JJ. At this position, the gap c3 between the switching spray 5A and the non-switching spray 4A is larger than the threshold value at which the Coanda effect acts, and the Coanda effect does not occur.

  As the cross-section JJ moves downstream from the cross-section KK, the deformation in which the direction of the major axis and the minor axis of the switching spray 5A changes proceeds, and the switching spray 5A and the non-switching spray 4A come closer. This is because the gap between the switching spray 5A and the non-switching spray 4A is reduced due to the occurrence of the axis-switching phenomenon in the switching spray 5A, and accordingly, the Coanda effect acts between the switching spray 5A and the non-switching spray 4A. It depends.

  In the cross section KK, the gap c4 between the switching spray 5A and the non-switching spray 4A is smaller than the threshold value at which the Coanda effect acts. In the cross-section L-L, the opposite ends of the switching spray 5A and the non-switching spray 4A are deformed and moved to start interference. As a result, in the cross section MM, after a predetermined time has elapsed after fuel injection, a collective spray 50 in which the switching spray 5A and the non-switching spray 4A are gathered is formed at a predetermined distance from the non-switching nozzle hole 391 and the switching nozzle hole 392. Is done.

  The shape, size, direction, penetration force, and injection amount distribution of the collective spray 50, the arrangement of the collective spray 50, and the like can be changed by changing the characteristics and the arrangement of the switching spray 5A and the non-switching spray 4A. Can be changed.

  In addition, the switching spray 5A is deformed by changing the direction of the major axis and the minor axis, so that the momentum exchange with the surrounding air greatly proceeds, and the penetration force becomes small. Therefore, by interfering with the non-switching spray 4A, the particles of the non-switching spray 4A and the movement of the air flow dragged by the particles are suppressed, and the penetration force of the non-switching spray 4A is also suppressed.

  The dashed-dotted line d of Fig.9 (a) has shown the spray shape in case the non-switching spray 4A is independent. In this way, the non-switching spray 4A has a reduced penetration force due to interference with the switching spray 5A, and the extension of the tip thereof is shortened compared to the case where it is alone.

  Further, the switching spray 5A is reduced in penetrating force and greatly mixed with the surrounding air, whereby atomization is improved and the difference from the atomization level of the non-switching spray 4A is reduced. That is, it is possible to form a non-circular collective spray 50 that is atomized at a predetermined distance downstream from the non-switching nozzle hole 391 and the switching nozzle hole 392 and has an asymmetric cross section.

  In FIG. 9, when the switching nozzle hole 392 is not used, the adjacency of adjacent sprays does not start until further downstream, and in some cases, aggregation does not occur. Accordingly, each spray continues to spread and the penetration force does not decrease. As a result, the momentum possessed by the spray is difficult to move to the air flow and atomization is insufficient.

  As described above, the spray groups (non-switching spray 4A and switching spray 5A) generated by the nozzle holes 39 belonging to the same nozzle hole group 393 are brought close to or gathered by the Coanda effect by the deformation of the switching spray 5A at a predetermined distance. It is possible to rapidly attenuate the penetration force. In addition, since the penetration force is reduced, mixing with ambient air proceeds and atomization is improved. Furthermore, the injection amount distribution and the spraying direction can be set according to each nozzle hole specification.

  In FIG. 9, the non-switching spray 4 </ b> A and the switching spray 5 </ b> A are combined to form the collective spray 50 having a non-target cross section. However, the collective spray is limited to this combination. However, the number and arrangement of sprays are not limited. For example, a combination of two non-switching sprays 4A and one switching spray 5A may be used, or two switching sprays 5A may be used. That is, at least one switching nozzle hole 392 may be included in each nozzle hole group 393.

  FIG. 10 shows another arrangement example of the injection hole 39 and the injection hole group 393 in the injection hole plate 33 according to the first embodiment. In the example shown in FIG. 10A, the nozzle hole group 393f (393g) includes two switching nozzle holes 392f (392g). As in this example, by arranging the two switching nozzle holes 392 so that the major axes thereof are substantially parallel to each other, a collective spray in which the major axes are connected by an axis-switching phenomenon is formed.

  In the example shown in FIG. 10B, the nozzle hole group 393h (393m) includes one non-switching nozzle hole 391h (391m) and two switching nozzle holes 392h (392m). The nozzle hole group 393h is composed of two switching nozzle holes 392h whose major axes face each other substantially in parallel, and a non-switching nozzle hole 391h disposed therebetween. The nozzle hole group 393j includes two switching nozzle holes 3921j whose major axes are substantially parallel to each other, and a switching nozzle hole 3922j disposed so that the major axes are orthogonal to each other.

  The collective spray formed by the nozzle hole groups 393h and 393j is more elongated in the longitudinal direction than the collective spray formed by the jet hole group 393f shown in FIG. As described above, by increasing the number of nozzle holes 39 included in each nozzle hole group 393, it is possible to form a collective spray having a more complicated shape.

  Next, in the first embodiment, the behaviors of the non-switching spray 4A and the switching spray 5A that belong to another spray group 393 and are generated by the non-switching nozzle hole 391 and the switching nozzle hole 392 that are adjacent to each other are shown in FIG. This will be described with reference to FIG.

  FIG. 11 shows the behavior of the non-switching spray 4A and the switching spray 5A generated by the non-switching nozzle hole 391c and the switching nozzle hole 392d shown in FIG. 11, (a) is a side view of each spray, and (b) is a cross-sectional view at a portion indicated by EE, FF,..., LL in (a).

  The non-switching nozzle hole 391c and the switching nozzle hole 392d are arranged at an interval L4 (L4> L3) so that the long axis of the switching nozzle hole 392d faces the non-switching nozzle hole 391c. The jet 4a injected from the non-switching nozzle hole 391c becomes the non-switching spray 4A, and the jet 5b injected from the switching nozzle 392d becomes the switching spray 5B.

  In FIG. 11, the switching spray 5B has a long axis direction facing the non-switching spray 4A before the occurrence of the axis-switching phenomenon, but as shown in a cross section JJ at a predetermined distance from the switching nozzle hole 392d. The direction of the major axis and minor axis begins to change.

  However, even in the cross-section LL where the non-switching spray 4A and the switching spray 5A are closest to each other, the gap c5 is larger than the threshold at which the Coanda effect acts. For this reason, the Coanda effect does not act on both the sprays 4A and 5B, and they proceed independently in the initial traveling direction. At this time, since the switching spray 5B does not interfere with the non-switching spray 4A, the penetration force of the non-switching spray 4A is not suppressed.

  In addition, when a plurality of switching sprays 5A are included, even after an axis-switching phenomenon occurs in the plurality of switching sprays 5A, the non-switching spray 4A is not affected by proximity, deformation, etc. The deformed shape of the switching spray 5A can be kept stable.

  FIG. 12 shows the behavior of the non-switching spray 4A and the switching spray 5C generated by the non-switching nozzle hole 391a and the switching nozzle hole 392e shown in FIG. 12, (a) is a side view of each spray, and (b) is a cross-sectional view at a portion indicated by EE, FF,..., LL in (a).

  The non-switching nozzle hole 391a and the switching nozzle hole 392e are arranged at an interval L5 so that the short axis of the switching nozzle hole 392e faces the non-switching nozzle hole 391a. The jet 4a injected from the non-switching nozzle 391a becomes the non-switching spray 4A, and the jet 5c injected from the switching nozzle 392e becomes the switching spray 5C.

  In FIG. 12, the short axis direction of the switching spray 5C is opposed to the non-switching spray 4A before the axis-switching phenomenon occurs, but as shown in a cross section JJ at a predetermined distance from the switching nozzle hole 392e. The direction of the major axis and minor axis begins to change.

  However, even in the cross-section HH where the non-switching spray 4A and the switching spray 5C are closest, the gap between them is larger than the threshold value at which the Coanda effect acts, and the Coanda effect does not occur. Furthermore, as the cross section JJ moves downstream from the cross section KK, the deformation in which the direction of the major axis and the minor axis of the switching spray 5C changes is advanced, and the gap between the switching spray 5C and the non-switching spray 4A is further increased. .

  For this reason, the Coanda effect does not act on both the sprays 4A and 5C, and both the sprays 4A and 5C proceed substantially in the initial traveling direction while being independent. At this time, since the switching spray 5C does not interfere with the non-switching spray 4A, the penetration force of the non-switching spray 4A is not suppressed.

  As described above, in the first embodiment, the arrangement of the injection hole 39 and the injection hole group 393 provided in the injection hole plate 33 can be variously modified. In any case, the switching spray 5A is -Before the deformation due to the switching phenomenon, the Coanda effect is reliably suppressed from acting between the adjacent non-switching spray 4A or the switching spray 5A.

  As a method of suppressing the Coanda effect from acting between the adjacent non-switching spray 4A and the switching spray 5A, a method of delaying the timing at which the Coanda effect occurs by providing a difference in the characteristics of the switching spray 5A and the non-switching spray 4A There is.

  Specifically, the method of making the average particle diameter of the switching spray 5A at the same distance from the non-switching nozzle hole 391 and the switching nozzle hole 392 larger than the average particle diameter of the non-switching spray 4A, or the break length of the switching spray 5A There are a method of making the break length of the non-switching spray 4A longer, a method of setting the penetration force of the switching spray 5A larger than the penetration force of the non-switching spray 4A, and the like.

  In realizing these methods, it is possible to utilize the fact that the level and direction of the contracted flow change depending on the nozzle hole shape difference between the non-switching nozzle hole 391 and the switching nozzle hole 392. For example, when the level and direction of the contracted flow are varied, the pressure loss (jet velocity) in the nozzle hole 39, the sectional area of the jet, the sectional shape, the arrangement, the direction, and the like can be varied, and the Coanda effect acts. It is possible to change the threshold value of the gap to be performed.

  Moreover, since the threshold value of the gap in which the Coanda effect acts also varies depending on the flow rate of each spray, the atomization level, the particle number density, the atmospheric pressure, and the like, it can be set to a desired threshold value by adjusting these.

  Further, in the first embodiment, the switching spray 5A is deformed by the axis-switching phenomenon and then generated by another nozzle hole 39 belonging to the same nozzle hole group 393 (non-switching spray 4A or switching spray 5A). Designed to be close or aggregated by the action of the Coanda effect. When the spray shape and size required by the close proximity of sprays can be achieved, it is not always necessary to aggregate them.

  11 and 12, the switching spray 5A (5C) generated by the switching nozzle hole 392 is generated by the non-switching nozzle hole 391 belonging to another spray group 393 even after being deformed by the axis-switching phenomenon. An example in which the Coanda effect does not act between the non-switching spray 4A and does not approach or aggregate has been described. However, after the switching sprays 5A and 5C are deformed due to the axis-switching phenomenon, they are brought close to or aggregated with the sprays generated by the nozzle holes 39 belonging to another spray group 393, so that a desired overall spray specification is obtained. May be realized, the Coanda effect may act.

  Next, an example of the shape of the entire spray formed by the fuel injection valve 1 according to Embodiment 1 will be described with reference to FIGS. 13 and 14. FIG. 13 shows sprays sprayed from the switching nozzle holes 392e and the nozzle hole groups 393a, 393b, 393c, and 393d of the nozzle hole plate 33 shown in FIG. 3 and the entire spray formed by the spray groups. In FIG. 13, (a) shows a cross-sectional shape in a plane perpendicular to the injection direction before the switching spray causes the axis-switching phenomenon, and (b) shows the cross-sectional shape perpendicular to the injection direction after the switching spray causes the axis-switching phenomenon. Yes.

  Further, FIG. 14 shows a case where the entire spray shown in FIG. 13 is viewed from the direction indicated by the arrow x in FIG. 13, that is, when viewed from a direction perpendicular to the Z axis of the fuel injection valve 1. . In FIG. 14, (a) to (d) show the time series change of each spray group until the entire spray is reached. Note that, when viewed from the direction of the arrow x, the non-switching spray 4A, the switching spray 5A, and the collective spray 50 overlap in the front-rear direction, and FIG. 14 shows only the sprays positioned forward.

  As shown in FIGS. 13 and 14, the switching spray 5 </ b> A injected from the five switching nozzle holes 392 provided in the nozzle hole plate 33 undergoes an axis-switching phenomenon at a predetermined distance from each nozzle hole 392, and the injection is performed. The direction of the major axis and the minor axis in the cross-sectional shape in the plane perpendicular to the direction changes. At this time, in the switching spray 5A, a considerable proportion of the momentum moves to the air, and the penetration force is greatly reduced.

  The switching spray 5A injected from the switching nozzle holes 392 belonging to the nozzle hole group 393 (switching nozzle holes 392c and 392d in FIG. 14) undergoes an axis-switching phenomenon, and then the non-switching that belongs to the same nozzle hole group 393. The Coanda effect acts between the nozzle holes 391 (in FIG. 14, non-switching nozzle holes 391c and 391d) and the non-switching spray 4A to form the collective spray 50, respectively.

  That is, the entire spray 60 formed by the nozzle hole plate 33 shown in FIG. 3 includes one switching spray 5A generated by a single switching nozzle 392e, a non-switching nozzle 391, and a switching nozzle 392. It includes four collective sprays 50 generated by four nozzle hole groups 393a, 393b, 393c, and 393d including one each.

  In the first embodiment, the case where the major axis and minor axis directions of the switching spray change by 90 degrees has been described. However, the present invention is not limited to this, and can be set to an arbitrary angle. Further, the shape of the switching spray 5A may be flatter in cross-sectional shape. When generating a spray having a large ratio between the major axis and the minor axis, the nozzle hole specifications may be set so that the major axis and minor axis directions change within a range in which the major axis direction is not divided. Further, the shape of the entire spray 60 can realize various variations such as a solid conical shape and a triangular shape as well as a hollow conical shape depending on the arrangement of the collective spray 50.

  From the above, according to the fuel injection valve 1 according to the first embodiment and the spray generation device including the fuel injection valve 1, at least one switching spray is included in each spray group generated by the plurality of nozzle hole groups 393. By including 5A, it is possible to control the cross-sectional shape in the plane perpendicular to the spraying direction of the spray by utilizing the axis-switching phenomenon.

  In addition, the switching spray 5A generated by the switching nozzle hole 392 belonging to the nozzle hole group 393 is generated by another nozzle hole 39 belonging to the same nozzle hole group 393 as the switching nozzle hole 392 after the occurrence of the axis-switching phenomenon. It is controlled so as to cause proximity or aggregation due to the Coanda effect between the sprays to be applied. This makes it possible to control the spray shape and the overall spray shape of each spray group generated by each nozzle hole group 393, and the degree of freedom in design of spray atomization, spray direction, penetration force, and injection amount distribution It is possible to achieve both improvement.

  In the first embodiment, an electromagnetic fuel injection valve has been described as an example of the fuel injection valve 1. However, the drive source may be another type, such as a piezo type or a mechanical type. Further, it can be applied to both intermittent injection valves and continuous injection valves.

  In the first embodiment, the fuel injection valve 1 is described as an example. However, the application of the fluid injection valve according to the present invention is not limited to this. Other applications include a wide range of applications such as painting, coating, pesticide spraying, cleaning, humidification, sprinklers, sprays for sterilization, cooling, and various sprays for agriculture, equipment, household, and personal use. The fluid injection valve according to the present invention can be incorporated in a spray generating device for various uses regardless of the drive source, the nozzle form, and the type of fluid to be sprayed.

Embodiment 2. FIG.
FIGS. 15A and 15B are diagrams schematically showing a spark ignition direct injection engine according to Embodiment 2 of the present invention, in which FIG. 15A shows stratified combustion (during piston rise), and FIG. 15B shows homogeneous combustion (piston). The state of descent) is shown. The spark ignition direct injection engine 6 according to the second embodiment includes the fuel injection valve 1 according to the first embodiment as a fuel injection valve that injects fuel into the combustion chamber 7.

  As shown in FIG. 15, an intake port 8 and an exhaust port 9 communicate with the combustion chamber 7 of the spark ignition direct injection engine 6, and each combustion chamber 7 side opening is interlocked with the piston 10. Thus, an intake valve 11 and an exhaust valve 12 that are opened and closed are provided. Further, the fuel injection valve 1 is disposed at a substantially central portion of the ceiling of the combustion chamber 7, and a spark plug 13 is disposed on the side thereof. In addition, arrangement | positioning of the fuel injection valve 1 and the ignition plug 13 is not limited to this.

  Since the configuration of the fuel injection valve 1 of the spark ignition direct injection engine 6 according to the second embodiment is the same as that of the first embodiment, detailed description thereof is omitted (see FIGS. 1 and 3). A valve seat 32 provided in the middle of the passage through which the valve flows, a valve body 35 provided so as to be capable of contacting and separating from the valve seat 32 and controlling the opening and closing of the passage, and a plurality of nozzle holes 39 provided downstream of the valve seat 32. The nozzle hole plate 33 is provided.

  Further, the plurality of nozzle hole groups 393 arranged on the nozzle hole plate 33 includes at least one switching nozzle hole 392, and the switching spray 5 </ b> A generated by the switching nozzle hole 392 is at a predetermined distance from the nozzle hole 392. An axis-switching phenomenon occurs, and the major axis and minor axis directions are changed in a cross-sectional shape in a plane perpendicular to the injection direction. Thereby, the cross-sectional shape in a plane perpendicular to the injection direction of the switching spray 5A can be changed.

  Further, after the occurrence of the axis-switching phenomenon, the switching nozzle 392 and the spray generated by another nozzle hole 39 belonging to the same nozzle hole group 393 cause proximity or aggregation due to the Coanda effect. Thus, the shape of each spray group and the entire spray 60 generated by each nozzle hole group 393 is controlled to a shape suitable for air-fuel mixture formation or combustion in the combustion chamber 7.

  In addition, the switching spray 5A can rapidly attenuate the penetration force of the spray at a predetermined distance by utilizing the fact that the momentum exchange with the surrounding air proceeds due to the deformation and the penetration force decreases. In addition, since the penetration force is reduced, mixing with ambient air proceeds and atomization is improved. Furthermore, the injection amount distribution and the spraying direction can be set according to each nozzle hole specification.

The switching spray 5 </ b> A controls whether or not the axis-switching phenomenon occurs due to at least one factor of the fuel injection pressure of the fuel injection valve 1, the pressure in the combustion chamber 7, or the air flow in the combustion chamber 7. Is done.

  In addition, the injection hole specifications including the injection hole diameter, the length, and the inclination of the switching injection hole 392 are set so as to generate the switching spray 5A in which the long axis is axisymmetric with respect to the short axis. Thereby, even after the occurrence of the axis-switching phenomenon, the shape becomes axisymmetric, which is convenient for stably stopping the spray near the spark plug 13.

  Further, in each nozzle hole group 393, until the switching spray 5A generated by the switching nozzle 392 causes an axis-switching phenomenon, the Coanda effect that induces the proximity of the adjacent spray is not spaced at intervals. The nozzle hole 39 is arranged, and the nozzle hole specifications including the nozzle hole diameter, the length, and the inclination, the flow velocity, the particle diameter, and the particle number density are set. In the second embodiment, each spray group is set so that the Coanda effect does not act between the adjacent spray groups even after the switching spray 5A causes the axis-switching phenomenon.

  For example, an injection hole plate 33 shown in FIG. 3 can be used in the spark ignition direct injection engine according to the second embodiment. As shown in FIG. 3, the switching nozzle hole 392e provided independently without belonging to the nozzle hole group 393 generates the switching spray 5A directed to the vicinity of the spark plug 13 by the axis-switching phenomenon.

  The state of the entire spray during stratified combustion and homogeneous combustion in the spark ignition direct injection engine 6 according to the second embodiment will be described with reference to FIG. At the time of stratified combustion shown in FIG. 15A, the air in the combustion chamber 7 is compressed by the rise of the piston 10, and the pressure in the combustion chamber 7 increases. For this reason, the penetration force of each spray group including the non-switching spray 4A and the switching spray 5A is smaller than that during homogeneous combustion.

  The switching spray 5 </ b> A generated by the switching nozzle hole 392 belonging to the spray group 393 undergoes an axis-switching phenomenon in the process of passing through the cylinder, and another nozzle hole 39 belonging to the same nozzle hole group 393 as the switching nozzle hole 392. Proximity or aggregation due to the Coanda effect occurs with the spray produced by

  Further, the switching spray 5A generated by the independently provided switching nozzle hole 392e causes an axis-switching phenomenon in the process of passing through the vicinity of the spark plug 13, and is directed to the vicinity of the spark plug 13. At the same time, the penetrating force is greatly reduced, and when passing through the vicinity of the spark plug 13, the penetrating force is lost, and the penetrating force stays in the vicinity of the spark plug 13.

  That is, the penetration force of the switching spray 5 </ b> A can be rapidly attenuated at a desired distance from the injection position to the vicinity of the ignition plug 13, thereby forming a rich air-fuel mixture having a desired cross-sectional shape in the vicinity of the ignition plug 13. This is advantageous for establishing stratified combustion.

  Further, each spray group is oriented so as to be in a mixed combustion state suitable for stratified combustion, and a penetration force is set so that collision with the cylinder liner 14 and the piston 10 surface is suppressed. As a result, the entire spray 60 is prevented from colliding with the cylinder liner 14 and the piston 10 surface, and forms a rich air-fuel mixture suitable for stratified combustion in the vicinity of the spark plug 13.

  On the other hand, at the time of the homogeneous combustion shown in FIG. 15B, the intake valve 11 is opened as the piston 10 descends, so that a strong air flow such as a tumble flow is generated in the combustion chamber 7. For this reason, the switching spray 5 </ b> A of each spray group follows the air flow in the combustion chamber 7 in the process of passing through the vicinity of the spark plug 13, and does not cause an axis-switching phenomenon and diffuses throughout the combustion chamber 7. Further, the non-switching spray 4A and the switching spray 5A generated by the nozzle holes 39 belonging to the same nozzle hole group 393 do not cause proximity or aggregation due to the Coanda effect.

  As described above, the spark ignition direct injection engine 6 according to Embodiment 2 can provide a large characteristic difference between the spray directed to the vicinity of the spark plug 13 and the spray not directed to the vicinity of the spark plug 13 during stratified combustion. By applying the switching spray 5A as spray directed to the vicinity of the spark plug 13, it is possible to form an air-fuel mixture suitable for stratified combustion in the vicinity of the spark plug 13 while avoiding collision with the spark plug 13. Further, at the time of homogeneous combustion, it is possible to follow the air flow in the process of passing through the vicinity of the spark plug 13 and to diffuse to the entire combustion chamber 7 without causing an axis-switching phenomenon.

  According to the second embodiment, in the spray group generated by the plurality of nozzle hole groups 393, at least one of the sprays included in each spray group is the switching spray 5A, thereby utilizing the axis-switching phenomenon. It is possible to control the cross-sectional shape in the plane perpendicular to the spraying direction of the spray, and it is possible to achieve both atomization of the spray and improvement of design freedom of the spraying direction, penetration force, and spray amount distribution. A spark ignition type direct injection engine 6 is obtained.

Embodiment 3 FIG.
FIGS. 16A and 16B are diagrams schematically showing a compression ignition type direct injection engine according to Embodiment 3 of the present invention. FIG. 16A shows a state when the piston is raised, and FIG. 16B shows a state when the piston is lowered. The compression ignition type direct injection engine 6A according to the third embodiment includes the fuel injection valve 1 according to the first embodiment as a fuel injection valve that injects fuel into the combustion chamber 7.

  As shown in FIG. 16, an intake port 8 and an exhaust port 9 communicate with the combustion chamber 7 of the compression ignition type direct injection engine 6 </ b> A, and an opening on each combustion chamber 7 side is interlocked with the piston 10. Thus, an intake valve 11 and an exhaust valve 12 that are opened and closed are provided. In addition, the fuel injection valve 1 is disposed at a substantially central portion of the ceiling of the combustion chamber 7. The arrangement of the fuel injection valve 1 is not limited to this.

  Since the configuration of the fuel injection valve 1 of the compression ignition type direct injection engine 6A according to the third embodiment is the same as that of the first embodiment, detailed description thereof is omitted (see FIGS. 1 and 3). A valve seat 32 provided in the middle of the passage through which the valve flows, a valve body 35 provided so as to be capable of contacting and separating from the valve seat 32 and controlling the opening and closing of the passage, and a plurality of nozzle holes 39 provided downstream of the valve seat 32. The nozzle hole plate 33 is provided.

  Further, the plurality of nozzle hole groups 393 arranged on the nozzle hole plate 33 includes at least one switching nozzle hole 392, and the switching spray 5 </ b> A generated by the switching nozzle hole 392 is at a predetermined distance from the nozzle hole 392. An axis-switching phenomenon occurs, and the major axis and minor axis directions are changed in a cross-sectional shape in a plane perpendicular to the injection direction. Thereby, the cross-sectional shape in a plane perpendicular to the injection direction of the switching spray 5A can be changed.

  Further, after the occurrence of the axis-switching phenomenon, the switching nozzle 392 and the spray generated by another nozzle hole 39 belonging to the same nozzle hole group 393 cause proximity or aggregation due to the Coanda effect. Thus, the shape of each spray group and the entire spray 60 generated by each nozzle hole group 393 is controlled to a shape suitable for air-fuel mixture formation or combustion in the combustion chamber 7.

  In addition, the switching spray 5A can rapidly attenuate the penetration force of the spray at a predetermined distance by utilizing the fact that the momentum exchange with the surrounding air proceeds due to the deformation and the penetration force decreases. In addition, since the penetration force is reduced, mixing with ambient air proceeds and atomization is improved. Furthermore, the injection amount distribution and the spray direction can be set according to each nozzle hole specification.

  The switching spray 5 </ b> A controls whether or not the axis-switching phenomenon occurs due to at least one factor of the fuel injection pressure of the fuel injection valve 1, the pressure in the combustion chamber 7, or the air flow in the combustion chamber 7. Is done. In addition, the injection hole specifications including the injection hole diameter, the length, and the inclination of the switching injection hole 392 are set so as to generate the switching spray 5A in which the long axis is axisymmetric with respect to the short axis.

  In each nozzle hole group 393, until the switching spray 5A generated by the switching nozzle 392 causes an axis-switching phenomenon, the Coanda effect that induces the proximity with the adjacent spray does not act at intervals. 39 is arranged, and the nozzle hole specifications including the nozzle hole diameter, length, and inclination, the flow velocity, the particle diameter, and the particle number density are set. In the third embodiment, each spray group is set so that the Coanda effect does not act between the adjacent spray groups even after the switching spray 5A causes the axis-switching phenomenon.

  The state of the overall spray when the piston is raised and when the piston is lowered in the compression ignition type direct injection engine 6A according to Embodiment 3 of the present invention will be described with reference to FIG. When fuel injection is performed when the piston is lifted as shown in FIG. 16A, the air in the combustion chamber 7 is compressed by the lift of the piston 10 and the pressure in the combustion chamber 7 is increased. For this reason, the penetration force of each non-switching spray 4A and switching spray 5A becomes smaller than under atmospheric pressure.

  The switching spray 5A generated by the switching nozzle 392 has an axis-switching phenomenon in the process of passing through the cylinder, and is generated by another nozzle 39 belonging to the same nozzle hole group 393 as the switching nozzle 392. Proximity or aggregation occurs due to the Coanda effect. Thereby, the penetration force of each spray group is significantly reduced, and a compact whole spray 60 is formed in the combustion chamber 7 near the compression top dead center.

  Note that the compression ignition type direct injection engine has a very high compression temperature and pressure in the vicinity of the compression top dead center, and when fuel is injected in this state, it is ignited before an appropriate air-fuel mixture is formed. And uneven combustion may occur. On the other hand, the compression ignition type direct injection engine 6A according to the third embodiment abruptly attenuates the penetration force of the switching spray 5A at a desired distance from the injection position to the cylinder inner surface, and thus a rich air-fuel mixture having a desired cross-sectional shape. It is convenient to spread the spray in the cylinder and establish the compression ignition combustion.

  Further, each spray group is oriented so as to be in a mixed state suitable for compression ignition combustion, and a penetration force is set so that collision with the cylinder liner 14 and the piston 10 surface is suppressed. As a result, the entire spray 60 is prevented from colliding with the cylinder liner 14 or the piston 10 surface, and forms an air-fuel mixture suitable for compression ignition combustion.

  On the other hand, when the piston is lowered as shown in FIG. 16B, the intake valve 11 is opened as the piston 10 is lowered, so that a strong air flow such as a tumble flow is generated in the combustion chamber 7. The switching spray 5 </ b> A follows the air flow in the process of passing through the combustion chamber 7, and does not cause an axis-switching phenomenon and diffuses throughout the combustion chamber 7. Further, the non-switching spray 4A and the switching spray 5A generated by the nozzle holes 39 belonging to the same nozzle hole group 393 do not cause proximity or aggregation due to the Coanda effect.

  Thus, the compression ignition type direct injection engine 6A according to the third embodiment forms an air-fuel mixture suitable for compression ignition combustion by utilizing the axis-switching phenomenon of the switching spray 5A when the piston is raised. Is possible. Further, when the piston descends, it is possible to follow the air flow in the process of passing through the combustion chamber 7 and diffuse it throughout the combustion chamber 7 without causing an axis-switching phenomenon.

  According to the third embodiment, in the spray group generated by the plurality of nozzle hole groups 393, by using at least one of the sprays included in each spray group as the switching spray 5A, the axis-switching phenomenon is utilized. It is possible to control the cross-sectional shape in the plane perpendicular to the spraying direction of the spray, and it is possible to achieve both atomization of the spray and improvement of design freedom of the spraying direction, penetration force, and spray amount distribution. A compression ignition type direct injection engine 6A is obtained.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted. The application of the fuel injection valve 1 according to the present invention is not limited to the spark ignition type direct injection engine 6 and the compression ignition type direct injection engine 6A, but can be applied to other types of engines.

For example, the fuel injection valve 1 according to the present invention can be applied to a premixed compression ignition (HCCI) engine. HCCI engine achieves a compression ignition such as diesel engines using gasoline, and aims to achieve ultra low fuel consumption while reducing the PM and NO _x. In order to expand the operating range in this HCCI engine, it is necessary to control ignition, and the diffusion state of fuel spray in the combustion chamber and the mixture formation state are very important factors. The spray control according to the invention can play a very effective role in the establishment of this combustion concept.

  Furthermore, the fuel injection valve 1 according to the present invention can be applied to a spark ignition type port injection engine. In that case, the desired spray specifications can be achieved by combining spray groups with different cross-sectional shapes, penetrating forces, or atomization levels for one spray, two sprays, and three sprays corresponding to intake one valve, two valves, and three valves. Is possible.

  INDUSTRIAL APPLICABILITY The present invention can be used as a fluid injection valve, in particular, a fuel injection valve mounted on an engine, a spray generation device including the same, and a direct injection engine.

1 fuel injection valve, 2 solenoid device, 3 valve device,
4a, 4b, 4c, 5a, 5b, 5c jet,
4A, 4B, 4C non-switching spray, 5A, 5B, 5C switching spray,
6 spark ignition direct injection engine, 6A compression ignition direct injection engine, 7 combustion chamber,
8 intake port, 9 exhaust port, 10 piston, 11 intake valve, 12 exhaust valve,
13 spark plug, 14 cylinder liner, 21 housing, 22 core,
23 coil, 24 amateur, 30 liquid film flow, 31 valve body, 32 valve seat,
32a Valve seat surface, 33 Injection hole plate, 34 Cover plate, 34a Top surface,
34b Thin portion, 34c Small diameter portion, 34d Large diameter portion, 35 Valve body, 36 Compression spring,
37 rod, 38 ball, 38a chamfered part, 38b flat part, 38c curved part,
39 nozzle hole, 40, 50 collective spray, 60 whole spray,
391 non-switching nozzle hole, 392 switching nozzle hole, 393 nozzle hole group.

Claims (22)

A valve seat provided in the middle of a passage through which a fluid flows, a valve body provided so as to be capable of contacting and separating from the valve seat and controlling opening and closing of the passage, and a nozzle hole provided downstream of the valve seat; A fluid injection valve that generates a plurality of spray groups by injecting fluid from a plurality of nozzle hole groups arranged in the nozzle hole body,
Each of the plurality of nozzle hole groups has a plurality of nozzle holes arranged close to each other, and at least one of the plurality of nozzle hole groups is long in a cross-sectional shape in a plane perpendicular to the fluid ejection direction. Including at least one switching nozzle for generating a switching spray having different lengths of the shaft and the short shaft,
The switching spray generated by the switching nozzle changes the direction of the major axis and the minor axis at a predetermined distance from the switching nozzle, and after the change, the same spray as the switching nozzle. A fluid injection valve characterized by being controlled so as to be brought close to or aggregated by the Coanda effect between sprays generated by another nozzle hole belonging to a hole group.   The switching spray generated by the switching nozzle is controlled so as to cause an axis-switching phenomenon at a predetermined distance from the switching nozzle, and changes the direction of the major axis and the minor axis. Item 2. The fluid injection valve according to Item 1.   The injection hole body is formed integrally with the valve seat, and the switching injection hole has a shape in which a cross-sectional shape perpendicular to the injection hole axis corresponding to the fluid injection direction has a major axis and a minor axis. The fluid injection valve according to claim 1 or 2, characterized by the above-mentioned.   4. The switching nozzle hole according to claim 1, wherein a cross-sectional shape perpendicular to a plate thickness direction of the nozzle hole body is a shape having a major axis and a minor axis. 5. Fluid injection valve.   The switching nozzle hole has a nozzle hole specification including a nozzle hole diameter, a length, and an inclination so as to generate a switching spray in which the major axis is substantially line symmetric with respect to the minor axis. The fluid injection valve according to any one of claims 1 to 4.   In the nozzle hole group including the switching nozzle hole, the plurality of nozzle holes belonging to the nozzle hole group are adjacent to the adjacent sprays until the switching spray generated by the switching nozzle causes an axis-switching phenomenon. 3. The fluid injection according to claim 2, wherein the Coanda effect for inducing the proximity of the nozzles is arranged at intervals that do not act on each other, and the nozzle hole specifications including the nozzle hole diameter, length, and inclination are set. valve.   In the nozzle hole group including the switching nozzle hole, each spray generated by the plurality of nozzle holes belonging to the nozzle hole group is at least until the switching spray generated by the switching nozzle causes an axis-switching phenomenon. The fluid injection valve according to claim 2 or 6, wherein the fluid injection valve is set to a flow velocity, a particle size, and a particle number density at which the Coanda effect for inducing proximity to adjacent sprays does not act on each other.   The nozzle hole group including the switching nozzle hole and another nozzle hole group adjacent to the nozzle hole group are adjacent to each other at least until the switching spray generated by the switching nozzle causes an axis-switching phenomenon. The coanda effect that induces the proximity of the nozzles is arranged at intervals that do not act on each other, and the nozzle hole specifications including the nozzle hole diameter, length, and inclination are set. 8. The fluid injection valve according to 7.   The switching spray generated by the switching nozzle holes is arranged in the spray direction of the entire spray composed of a plurality of spray groups by being close to or assembled with a spray generated by another nozzle hole belonging to the same nozzle hole group. The fluid according to any one of claims 1 to 8, wherein the cross-sectional shape at right angles, the penetrating force distribution of the whole spray, or the injection amount distribution perpendicular to the spray direction of the whole spray is controlled. Injection valve.   A fluid injection valve according to any one of claims 1 to 9, fluid supply means for supplying fluid to the fluid injection valve, and control means for controlling the operation of the fluid injection valve. A spray generator characterized by the above. A direct injection type engine having a fuel injection valve for injecting fuel into a combustion chamber, wherein the fuel injection valve is provided in the middle of a passage through which fuel flows, and can be brought into contact with and separated from the valve seat A valve body that controls opening and closing of the passage, and a nozzle hole body that is provided downstream of the valve seat, and injects fuel from a plurality of nozzle hole groups disposed in the nozzle hole body. Generating a spray group of
Each of the plurality of nozzle hole groups has a plurality of nozzle holes arranged close to each other, and at least one of the plurality of nozzle hole groups is long in a cross-sectional shape in a plane perpendicular to the fuel injection direction. Including at least one switching nozzle for generating a switching spray having different lengths of the shaft and the short shaft,
The switching spray generated by the switching nozzle changes the direction of the major axis and the minor axis at a predetermined distance from the switching nozzle, and after the change, the same spray as the switching nozzle. A direct-injection engine controlled to cause proximity or aggregation due to the Coanda effect between sprays generated by another nozzle hole belonging to a hole group.   The switching spray generated by the switching nozzle is controlled so as to cause an axis-switching phenomenon at a predetermined distance from the switching nozzle, and changes the direction of the major axis and the minor axis. Item 11. The direct injection engine according to Item 11.   The injection hole body is formed integrally with the valve seat, and the switching injection hole has a shape in which a cross-sectional shape perpendicular to the injection hole axis corresponding to the fuel injection direction has a major axis and a minor axis. The direct injection engine according to claim 11 or 12, characterized in that:   14. The switching nozzle hole according to claim 11, wherein a cross-sectional shape perpendicular to the plate thickness direction of the nozzle hole body is a shape having a major axis and a minor axis. Direct injection engine.   Whether the switching spray generated by the switching nozzle causes an axis-switching phenomenon due to at least one of the fuel injection pressure of the fuel injection valve, the pressure in the combustion chamber, or the air flow in the combustion chamber. The direct injection type engine according to claim 12, wherein the direct injection type engine is controlled.   The switching spray generated by the switching nozzle holes is arranged in the spray direction of the entire spray composed of a plurality of spray groups by being close to or assembled with a spray generated by another nozzle hole belonging to the same nozzle hole group. The direct cross-sectional shape according to any one of claims 11 to 15, wherein the cross-sectional shape at right angles, the penetrating force distribution of the whole spray, or the injection amount distribution perpendicular to the spray direction of the whole spray is controlled. Injection engine.   13. The direct injection engine according to claim 12, wherein a spark ignition type is employed in which a spark is generated by an ignition plug provided in the combustion chamber and an air-fuel mixture in the combustion chamber is ignited as an ignition method.   When stratified combustion is performed in the combustion chamber, the switching spray generated by the switching nozzle causes an axis-switching phenomenon in the process of passing through the vicinity of the spark plug, and is directed to the vicinity of the spark plug and penetrated. 18. The direct injection type engine according to claim 17, wherein the direct injection type engine is controlled so as to lose its penetrating force when it passes through the vicinity of the spark plug and stays in the vicinity of the spark plug.   When performing homogeneous combustion in the combustion chamber, the switching spray generated by the switching nozzle follows the air flow in the combustion chamber in the process of passing through the vicinity of the spark plug, and does not cause an axis-switching phenomenon. 19. The direct injection engine according to claim 17, wherein the direct injection engine is controlled so as to diffuse throughout the combustion chamber.   13. The direct injection engine according to claim 12, wherein a compression ignition type is employed in which the air-fuel mixture in the combustion chamber is compressed by a piston and self-ignition is performed as an ignition system.   When fuel injection is performed when the piston rises in the combustion chamber, the switching spray generated by the switching nozzle hole causes an axis-switching phenomenon, and the penetrating force is reduced. 21. The direct injection engine of claim 20, wherein the direct injection engine is controlled to form a compact overall spray.   When fuel injection is performed when the piston descends in the combustion chamber, the switching spray generated by the switching nozzle follows the air flow in the combustion chamber and does not cause an axis-switching phenomenon, and does not occur in the entire combustion chamber. The direct injection engine according to claim 20 or 21, wherein the direct injection engine is controlled to diffuse.

Images