JP4502828B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve mainly used in a fuel supply system of an internal combustion engine. A nozzle having a plurality of fuel injection holes located on the downstream side of the valve seat and arranged around the centerline of the valve seat is integrally formed with the same material as the valve seat member. And a recess for receiving the nozzle is provided on the front end surface of the valve seat member, and the fuel injection holes of the nozzle are disposed between the valve body and the valve seat when the valve body is opened. The present invention relates to an improvement in a fuel injection valve in which a main flow of fuel that has passed is formed so as to directly collide with the inner surfaces of the respective fuel injection holes, and fuel injected from the fuel injection holes is supplied to an intake port of an engine.

  A valve body, a valve seat member having an annular and conical valve seat on which the valve body is seated so as to be openable and closable, and a valve seat member connected to the front end of the valve seat member so as to be positioned downstream of the valve seat; An electromagnetic fuel injection valve including a nozzle having a plurality of fuel injection holes arranged around the center line is already known as disclosed in Patent Documents 1 and 2 below.

By the way, in recent internal combustion engines, demands for output improvement and low pollution of exhaust gas are increasing. Therefore, the fuel injection valve has a large flow rate characteristic capable of injecting a large amount of fuel with good responsiveness in order to improve the output, and in order to purify the exhaust gas, the injected fuel is atomized and the intake passage of the fuel is injected. Atomization and penetration properties that suppress adhesion to the inner wall are important.
JP 2000-97129 A Japanese Patent No. 3027919

  However, since the fuel flow path connecting between the valve seat part and the fuel injection hole is also bent in both of Patent Documents 1 and 2, the fuel that has passed through the valve seat part when the valve body is opened. Before the fuel reaches the fuel nozzle hole of the nozzle, the pressure loss of the fuel increases, and it is difficult to satisfy the above-mentioned large flow characteristics and atomization / penetration.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide the fuel injection valve capable of simultaneously satisfying the large flow rate characteristics and atomization / penetration properties as described above.

In order to achieve the above-mentioned object, the present invention provides a valve seat member having an annular valve seat, which is formed of a conical surface having a small diameter toward the front of a fuel injection valve and on which a valve body is slidably seated. A nozzle having a plurality of fuel injection holes located on the downstream side of the valve seat and disposed around the center line of the valve seat is integrally formed of the same material as the valve seat member, and the front end of the valve seat member A concave portion for receiving the nozzle is provided on the surface, and when the valve body is opened, the main flow of the fuel that has passed between the valve body and the valve seat is the fuel injection hole of the nozzle. A fuel injection valve formed so as to directly collide with an inner surface of a hole and supplying fuel injected from the fuel injection hole to an intake port of an engine, wherein the valve body is annularly seated on the valve seat The tip surface on the tip side of the sealing surface of the nozzle and the nozzle facing the tip surface Each of the end surfaces has a conical surface or a spherical surface having a small diameter toward the front of the fuel injection valve and extending to the front of the fuel injection valve from the fuel injection hole, and between the inner end surface of the nozzle and the valve seat. An annular step portion that avoids mutual contact between the valve body and the nozzle is formed so that a space is formed between the front end surface of the valve body and the inner end surface of the nozzle. The nozzles are disposed so as to open to the inner end face of the nozzle on the inner peripheral side with respect to the annular step portion, and so that the extension line of the bus bar of the valve seat intersects the inner surface of each of the fuel injection holes. The inner peripheral surface of the concave portion exerts a Coanda effect on the conical spray foam formed by the fuel injected from each fuel injection hole, so that the intake port 50a of the engine E does not disturb the spray foam. Direct downstream Sea urchin, thereby forming a conical shape whose diameter increases toward the front end face of the valve seat member is formed by intersection of the imaginary extended surface of the outer end face of the nozzle and the virtual extension plane of the inner peripheral surface of said recess The first feature is that the diameter of the circle is set smaller than the effective diameter of the valve seat.

  In addition to the first feature, the present invention has a second feature that the height from the front end surface of the valve seat member to the valve seat is set to 1 mm or more.

  According to the first feature of the present invention, when the valve element is opened, the main flow of the fuel passing between the valve element and the valve seat directly collides with the inner surface of the fuel injection hole with almost no pressure loss. Thus, the fuel injected from the fuel injection holes can be effectively atomized and a high-speed spray foam can be formed. Therefore, this spray foam has a very high flow rate and high penetration, so there is little that adheres to the inner wall of the intake port of the engine, and there is little fuel pressure loss, so a large flow rate of fuel can be secured, and engine output is improved. And contribute to lower pollution of exhaust gas.

  Further, the valve seat is constituted by a conical surface having a small diameter toward the front of the fuel injection valve, and the tip surface of the valve body and the inner end surface of the nozzle are conical or spherical surfaces having a small diameter toward the front of the fuel injection valve. As a result, the bending of the fuel flow path from the valve seat to each fuel injection hole can be reduced to reduce internal pressure loss, and high energy fuel can be guided to each fuel injection hole. , It can contribute to further improvement of the large flow characteristics of fuel.

  Furthermore, the integration of the valve seat member and the nozzle with the same material eliminates the process of joining the nozzle to the valve seat member (welding) and frees you from concerns about thermal distortion of the valve seat and nozzle due to welding. Therefore, it is possible to improve the valve tightness and to improve the accuracy of the position and orientation of the fuel injection hole in the nozzle, so that the spray foam formed by the fuel injected from the fuel injection hole Can bring about stabilization. In addition, since the nozzle whose inner end surface is a conical surface or a spherical surface has extremely high rigidity, it is possible to easily perform thin-wall processing by cutting the nozzle.

  Furthermore, by receiving the nozzle in the recess formed in the front end surface of the valve seat member, the valve seat member itself can protect the nozzle from contact with other objects, and a special protective cap becomes unnecessary. In addition, the recess can suppress dripping due to fuel blowback.

  Further, by forming the inner peripheral surface of the concave portion into a conical shape whose diameter increases toward the front end surface of the valve seat member, the concave portion exhibits a Coanda effect and is formed by a fuel injected from the nozzle. Without disturbing the spray form, it can be accurately directed downstream of the intake port 50a of the engine E, which can contribute to the improvement of penetration.

Furthermore, by setting the diameter of a circle formed by the intersection of the virtual extension surface of the inner peripheral surface of the recess and the virtual extension surface of the outer end surface of the nozzle to be smaller than the effective diameter of the valve seat, The thickness of the valve seat member in the axial direction can be sufficiently secured without being obstructed by the concave portion, and great rigidity can be imparted to the valve seat. Therefore, the valve seat can be easily processed with high accuracy and the valve tightness can be improved.

  Furthermore, the annular step formed between the valve seat and the inner end face of the nozzle can not only prevent the mutual interference between the valve body and the nozzle and improve the valve tightness but also pass through the valve seat. This facilitates the direct introduction of the mainstream fuel into the fuel nozzle, greatly contributing to the improvement of the fuel's large flow characteristics and penetration.

  In addition, due to the presence of the annular step portion, the space formed between the valve body and the nozzle inside the fuel injection hole group is a dead space that does not need to have a fuel flow path function. By appropriately setting the cone angle or radius of the conical surface or spherical surface constituting the inner end face of the nozzle, this is narrowed as much as possible within the range that avoids mutual interference between the valve body and the nozzle, thereby reducing the dead space and changing the temperature. It is possible to stabilize the fuel injection characteristic against the above.

  Further, when the annular valve seat is processed, the annular step portion prevents interference between the cutting tool and the nozzle, and the valve seat can be processed easily and accurately.

  Further, according to the second feature of the present invention, since the height from the front end surface of the valve seat member to the valve seat is increased, the axial thickness of the valve seat member in the valve seat portion is further increased. The wall thickness is sufficient to give the valve seat high rigidity.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  1 is a longitudinal sectional side view of an essential part of an engine equipped with an electromagnetic fuel injection valve according to a first embodiment of the present invention, FIG. 2 is an enlarged longitudinal side view of the fuel injection valve, and FIG. 3 is a nozzle of the fuel injection valve. 4 is an enlarged view of the peripheral portion, FIG. 4 is a view taken in the direction of the arrow 4 in FIG. 3, FIG. 5 is a view showing the opened state of the fuel injection valve, a corresponding view with FIG. It is a principal part longitudinal cross-sectional view of a fuel injection valve.

  First, a description will be given of the first embodiment of the present invention shown in FIGS.

  In FIG. 1, an intake manifold 51 is joined to a side surface of the cylinder head 50 of the engine E where the intake port 50 a is opened, and the electromagnetic fuel injection valve I of the present invention is attached to the intake manifold 51. The front end face of the fuel injection valve I is directed to the downstream end of the intake port 50a, and the spray form formed by the fuel injected from the fuel injection valve I when the intake valve 52 that opens and closes the downstream end of the intake port 50a is opened. F is supplied toward the downstream end of the intake port 50a.

  In FIG. 2, the valve housing 2 of the fuel injection valve I is connected to a cylindrical valve seat member 3 having a valve seat 8 at the front end and a rear end portion of the valve seat member 3 coaxially and fluid-tightly. The magnetic cylinder 4, the nonmagnetic cylinder 6 coaxially and liquid-tightly coupled to the rear end of the magnetic cylinder 4, and the coaxial and liquid-tightly coupled to the rear end of the nonmagnetic cylinder 6 The fixed core 5 and the fuel inlet cylinder 26 connected coaxially to the rear end of the fixed core 5 are configured.

  The valve seat member 3 has a cylindrical guide hole 9 and an annular valve seat 8 (see FIG. 3) connected to the front end of the guide hole 9. The valve seat member 3 includes a valve seat 8. The nozzle 10 located on the inner peripheral side, that is, on the downstream side is integrally formed. Specifically, the valve seat member 3 and the nozzle 10 are integrally formed by cutting the same material. A recess 13 (see FIGS. 3 and 4) for receiving the nozzle 10 is formed on the front end surface of the valve seat member 3.

  As shown in FIGS. 3 and 4, the nozzle 10 is provided with a plurality of fuel injection holes 11, 11..., Which are annularly arranged around the center line Y of the valve seat 8 and the nozzle 10. These fuel injection holes 11, 11... Are arranged so as to open to the inner end surface 10 a of the nozzle 10 on the inner peripheral side with respect to the annular step portion 15 described later.

  Returning to FIG. 2, a hollow cylindrical fixed core 5 is press-fitted into the inner peripheral surface of the nonmagnetic cylindrical body 6 from the rear end side thereof, whereby the nonmagnetic cylindrical body 6 and the fixed core 5 are coaxial with each other. Combined. At this time, a portion that does not fit with the fixed core 5 remains at the front end portion of the nonmagnetic cylindrical body 6, and the valve assembly V is accommodated in the valve housing 2 extending from the portion to the valve seat member 3.

  The valve assembly V is connected to the valve rod portion 17 including a valve portion 16 that opens and closes with respect to the valve seat 8 and a valve rod portion 17 that supports the valve portion 16, and is connected to the valve rod portion 17. It consists of a movable core 12 that straddles the cylindrical body 6 and is inserted into them and placed on the fixed core 5 on the same axis. The valve rod portion 17 is formed to have a smaller diameter than the guide hole 9, and a journal portion 17 a that protrudes in the radial direction and is slidably supported on the inner peripheral surface of the guide hole 9 is integrally formed on the outer periphery thereof. Is formed. In addition, a journal portion 17 b is formed on the outer periphery of the movable core 12 so as to be slidably supported on the inner peripheral surface of the magnetic cylindrical body 4.

  The valve assembly V includes a vertical hole 19 that ends from the rear end surface of the movable core 12 before the valve portion 16, and a plurality of first horizontal holes 20 a that communicate the vertical hole 19 with the outer peripheral surface of the movable core 12. A plurality of second lateral holes 20b are provided that allow the vertical holes 19 to communicate with the outer peripheral surface of the valve rod part 17 between the journal part 17a and the valve part 16. At that time, an annular spring seat 24 facing the fixed core 5 is formed in the middle of the vertical hole 19.

  The fixed core 5 is made of a ferrite-based high hardness magnetic material. On the other hand, in the movable core 12, a collar-like high-hardness stopper element 14 that embeds a later-described valve spring 22 is embedded in a suction surface opposite to the suction surface of the fixed core 5. The stopper element 14 has its outer end slightly protruded from the suction surface of the movable core 12 and is normally opposed to the suction surface of the fixed core 5 with a gap corresponding to the valve opening stroke of the valve body 18. The

  The fixed core 5 has a vertical hole 21 that communicates with the vertical hole 19 of the movable core 12, and a fuel inlet cylinder 26 that communicates internally with the vertical hole 21 is integrally connected to the rear end of the fixed core 5. The fuel inlet cylinder 26 is composed of a reduced diameter portion 26a connected to the rear end of the fixed core 5 and a subsequent enlarged diameter portion 26b, and a slotted pipe shape press-fitted into the vertical hole 21 from the reduced diameter portion 26a. A valve spring 22 for biasing the movable core 12 toward the valve closing side of the valve body 18 is provided between the retainer 23 and the spring seat 24. At that time, the set load of the valve spring 22 is adjusted by the depth of fitting of the retainer 23 into the vertical hole 21. A fuel filter 27 is mounted in the enlarged diameter portion 26b.

  A coil assembly 28 is fitted to the outer periphery of the valve housing 2 so as to correspond to the fixed core 5 and the movable core 12. The coil assembly 28 includes a bobbin 29 fitted to the outer peripheral surface from the rear end portion of the magnetic cylindrical body 4 to the fixed core 5 and a coil 30 wound around the bobbin 29. The front end of the coil housing 31 that surrounds 28 is welded to the outer peripheral surface of the magnetic cylindrical body 4, and the rear end is welded to the outer peripheral surface of the yoke 5 a that protrudes in a flange shape from the outer periphery of the rear end portion of the fixed core 5. The coil housing 31 has a cylindrical shape, and a slit 31a extending in the axial direction is formed on one side.

  A part of the magnetic cylinder 4, the coil housing 31, the coil assembly 28, the fixed core 5, and the front half of the fuel inlet cylinder 26 are embedded in a synthetic resin cylindrical mold part 32 by injection molding. At that time, the mold portion 32 is filled into the coil housing 31 through the slit 31a. A coupler 34 protruding in one side is integrally formed in the middle portion of the mold portion 32, and the coupler 34 holds a current-carrying terminal 33 connected to the coil 30.

  As shown in FIG. 3, the annular valve seat 8 is constituted by a conical surface having a small diameter toward the front of the fuel injection valve I, and the annular sealing surface 16a of the valve portion 16 seated on the annular valve seat 8 is a convex spherical surface. The tip surface 16b of the valve portion 16 is formed in a conical surface having a tangent to the sealing surface 16a as a generating line. The tip surface 16b is formed so as to extend from the fuel injection hole 11 to the front of the fuel injection valve I even when the valve portion 16 is separated from the valve seat 8 (see FIG. 5).

  On the other hand, the inner end surface 10a and the outer end surface of the nozzle 10 are also configured as conical surfaces having a small diameter toward the front of the fuel injection valve I, and thus have a generally convex shape toward the front of the fuel injection valve I. . The inner end face 10 a is also formed to extend from the fuel injection hole 11 to the front of the fuel injection valve I. An annular step portion 15 is provided between the valve seat 8 and the inner end surface 10 a of the nozzle 10 to secure a conical space 25 between the inner end surface 10 a of the nozzle 10 and the valve portion 16. The space 25 avoids mutual contact between the valve portion 16 and the nozzle 10, ensures seating of the valve portion 16 on the valve seat 8, and contributes to ensuring valve tightness.

  The plurality of fuel injection holes 11, 11... Which are formed in the nozzle 10 and are arranged in an annular shape around the center line Y are the main flow S of fuel passing between the valve portion 16 and the valve seat 8 (see FIG. 5). ) Incline in the direction away from the center line Y so as to directly collide with the inner surface of each of the fuel injection holes 11, and the inner surface of each fuel injection hole 11 is the bus bar of the conical valve seat 8. It arrange | positions so that it may intersect with the extended line L.

  Here, when the cone angle of the inner end surface 10a of the nozzle 10 is α, the cone angle of the valve seat 8 is β, and the cone angle of the tip surface 16b of the valve portion 16 is γ, these are expressed by the following formulas (1) to (1) 3) is established.

α> γ (1)
α> β (2)
10 ° ≦ θ ≦ 30 ° (3)
Where θ = α-β
Further, when the effective diameter of the valve seat 8 is D1, and the pitch circle diameter of the plurality of annular fuel injection holes 11, 11,... Is D2, the valve seat 8 and the fuel injection holes 11, 11 are established so that the following equation is established. ... are arranged close to each other.

D1 / D2 ≦ 1.5 (4)
The recess 13 that is formed on the front end surface of the valve seat member 3 and receives the nozzle 10 is formed in a conical shape whose inner peripheral surface increases in diameter toward the front end surface of the valve seat member 3. At this time, the diameter D3 of the circle formed by the intersection of the diameter of the inner peripheral surface of the recess 13 with a small diameter , that is, the virtual extension surface of the inner periphery of the recess 13 and the virtual extension surface of the outer end surface of the nozzle 10 Is set smaller than the effective diameter D1 of the valve seat 8. That is,
D3 <D1 (5)
The height H from the front end surface of the valve seat member 3 to the valve seat 8 is set to 1 mm or more.

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

  When the coil 30 is demagnetized, the valve assembly V is pressed forward by the biasing force of the valve spring 22, and the valve body 18 is seated on the valve seat 8. In this state, the fuel pumped from the fuel pump (not shown) to the fuel inlet cylinder 26 passes through the pipe-like retainer 23, the vertical hole 19 of the valve assembly V, and the first and second horizontal holes 20a and 20b. 3 is put on standby and used for lubrication around the journal portions 17a and 17b of the valve assembly V.

  When the coil 30 is energized by energization, the magnetic flux generated by the coil 30 sequentially travels through the fixed core 5, the coil housing 31, the magnetic cylindrical body 4, and the movable core 12, and the movable core 12 of the valve assembly V is set by the magnetic force. Since the valve portion 16 of the valve body 18 is separated from the valve seat 8 of the valve seat member 3 as shown in FIG. 5, the mainstream of the high-pressure fuel in the valve seat member 3 is sucked by the fixed core 5 against the load. S advances to the nozzle 10 side along the conical surface of the valve seat 8.

  By the way, the plurality of fuel injection holes 11, 11... In the annular arrangement of the nozzle 10 are arranged so that the inner surface of each fuel injection hole 11 intersects with the extension line L of the generatrix of the conical valve seat 8. The main flow S of the fuel directed directly from the valve portion 16 and the valve seat 8 to each fuel injection hole 11 collides with the inner surface of each fuel injection hole 11 without pressure loss, and other fuels The narrow conical space 25 between the nozzle 16 and the nozzle 10 quickly joins toward the nearest fuel injection hole 11, so that a relatively large amount of fuel is squeezed at each fuel injection hole 11 to accelerate the flow and the nozzle 10 is injected forward.

  In this way, the main flow S of the fuel that has passed through the valve seat 8 directly collides with the inner surface of the fuel injection holes 11, 11,... With almost no pressure loss, the conical space 25 is narrow, and fuel other than the main flow S quickly .., And reaches the fuel injection holes 11, 11..., And at this time, the pressure loss is extremely small. As a result, the fuel flow in the fuel injection holes 11, 11. It is possible to effectively atomize the fuel injected from the fuel injection holes 11, 11..., And to form a high-speed spray foam F. Therefore, since this spray form F has a very high flow rate and high penetration, there is very little loss of fuel adhering to the inner wall of the intake port 50a of the engine E, and fuel consumption can be reduced. In addition, a small fuel pressure loss means that a large flow rate of fuel can be secured. Thus, the electromagnetic fuel injection valve I of the present invention can satisfy the large flow rate characteristics and atomization / penetration properties of the fuel at the same time, so that it can greatly contribute to the improvement of the output of the engine E and the low pollution of the exhaust gas. it can.

  In particular, the annular step portion 15 formed between the valve seat 8 and the inner end surface 10a of the nozzle 10 not only avoids mutual interference between the valve portion 16 and the nozzle 10, but also the fuel that has passed through the valve seat 8 portion. This facilitates the direct introduction of the main flow S into each fuel injection hole 11 and greatly contributes to the improvement of the large flow rate characteristic and penetration of the fuel.

  Further, due to the presence of the annular step portion 15, the space 25 formed between the valve portion 16 and the nozzle 10 is a dead space that does not need to have a fuel flow path function, inside the fuel injection holes 11, 11,. Therefore, this can be narrowed as much as possible within the range in which mutual interference between the valve portion 16 and the nozzle 10 is avoided, the dead space can be reduced, and the fuel injection characteristics against temperature change can be stabilized.

  In this case, as shown in the above equation (1), if the cone angle γ of the tip surface 16b of the valve portion 16 is set smaller than the cone angle α of the inner end surface 10a of the nozzle 10, the gap between the valve portion 16 and the nozzle 10 is set. Is reduced as it approaches the center line Y of the nozzle 10, and the volume of the dead space inside the fuel injection holes 11, 11 ... group formed between the valve portion 16 and the nozzle 10 can be effectively reduced. Thus, the fuel injection characteristics against temperature changes can be further stabilized.

  Further, the front end surface 16b of the valve portion 16, the valve seat 8 and the inner end surface 10a of the nozzle 10 are formed of a conical surface having a small diameter toward the front of the fuel injection valve I, so that the valve portion 16 and the valve seat 8 The internal pressure loss can be reduced by reducing the bending of the fuel flow path from the space to each fuel injection hole 11, and high energy fuel can be guided to each fuel injection hole 11. Improvements can be made. In addition, since the nozzle 10 with the inner end surface 10a having a conical surface has extremely high rigidity, it is possible to easily perform thin-wall processing by cutting the nozzle 10.

  Further, as shown in the above equations (2) and (3), the conical angle α of the inner end surface 10a of the nozzle 10 is set to be 10 to 30 ° larger than the conical angle β of the valve seat 8, thereby allowing the main flow of fuel. When the collision incident angle of S on the inner surface of each fuel injection hole 11 approaches 90 °, a severe impact occurs, and good atomization of the injected fuel and high penetration can be effectively obtained.

  If the difference θ between the cone angle α of the inner end surface 10a of the nozzle 10 and the smaller cone angle β of the valve seat 8 is 30 ° or more, collision incidence of the main flow S of fuel on the inner surface of the fuel injection hole 11 occurs. As the angle decreases, the axial component of the fuel injection hole 11 of the main flow S increases to reduce the collision energy, making it difficult to obtain good atomization of the fuel. If the difference θ is 10 ° or less, An effective collision of the main flow S of the fuel that has passed through the valve seat 8 against the inner surface of each fuel injection hole 11 does not occur.

  Further, if the valve seat 8 and the fuel injection holes 11, 11... Are arranged close to each other according to the equation (4), the responsiveness from the opening of the valve body 18 to the fuel injection can be improved. It can contribute to the improvement of high rotation and high output performance. When D1 / D2 exceeds 1.5, the distance between the valve seat 8 and the fuel injection holes 11, 11,... Becomes too large, not only the responsiveness decreases, but also the inner surface of each fuel injection hole 11 of the fuel main flow S. No effective collision can be obtained.

  Furthermore, by integrally forming the valve seat member 3 and the nozzle 10 with the same material, the step of joining the nozzle 10 to the valve seat member 3 (welding) is eliminated, and the assembly of the fuel injection valve I is improved. At the same time, it is freed from concerns about thermal distortion of the valve seat 8 due to welding. Therefore, it is possible to improve the accuracy of the valve seat 8, and thus the valve tightness, and to improve the accuracy of the position and orientation of the fuel injection holes 11, 11,. Stabilization of the spray foam F formed by the injected fuel from the holes 11, 11. When the annular valve seat 8 is processed, the annular step 15 between the valve seat 8 and the inner end surface 10a of the nozzle 10 prevents interference between the cutting tool and the nozzle 10, and the valve seat 8 can be processed easily. Can be done accurately.

  Since the front end face of the valve seat member 3 is formed with a recess 13 for receiving the nozzle 10 integral with the valve seat member 3, the valve seat member 3 itself can protect the nozzle 10 from contact with other objects. This eliminates the need for a special protective cap. In addition, the recess 13 can also play a role of suppressing dripping due to fuel blowback.

  Further, the concave portion 13 is formed in a conical shape whose inner peripheral surface is enlarged in diameter toward the front end surface of the valve seat member 3, so that a conical effect is exerted and a conical formed by the injected fuel from the nozzle 10. Without disturbing the mist-like spray form F, it can be accurately directed downstream of the intake port 50a of the engine E, contributing to improved penetration.

  Furthermore, the axial direction of the valve seat member 3 in the valve seat 8 portion is set by setting the diameter D3 of the inner peripheral surface small diameter portion of the concave portion 13 to be smaller than the effective diameter D1 of the valve seat 8 as shown in the equation (5). The wall thickness can be sufficiently secured without being obstructed by the recess 13, and a great rigidity can be imparted to the valve seat 8. Therefore, the valve seat 8 can be easily processed with high accuracy, and the valve tightness can be enhanced. At this time, as described above, if the height from the front end surface of the valve seat member 3 to the valve seat 8 is set to 1 mm or more, the axial thickness of the valve seat member 3 at the valve seat 8 portion is determined as follows. The size is sufficient to provide high rigidity.

  Next, a second embodiment of the present invention shown in FIG. 6 will be described.

  In this second embodiment, the distal end surface 16b of the valve portion 16 is formed of a spherical surface having the same radius R1 as the annular sealing surface 16a seated on the valve seat 8, and the inner end surface 10a of the nozzle 10 opposed thereto has the radius R1. It is composed of a spherical surface having a larger radius R2. Since other configurations are the same as those of the previous embodiment, portions corresponding to those of the previous embodiment in FIG. 6 are denoted by the same reference numerals as those of the previous embodiment, and redundant description is omitted. Also according to the second embodiment, the same operational effects as the previous embodiment can be exhibited.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal side view of a main part of an engine equipped with an electromagnetic fuel injection valve according to a first embodiment of the present invention. The expanded vertical side view of the said fuel injection valve. The enlarged view of the nozzle peripheral part of the fuel injection valve. FIG. 4 is a view taken in the direction of arrow 4 in FIG. 3. FIG. 4 is a view corresponding to FIG. 3, showing an open state of the fuel injection valve. The principal part longitudinal cross-sectional view of the fuel injection valve which concerns on 2nd Example of this invention.

3 ... Valve seat member 8 ... Valve seat 10 ... Nozzle 10a ... Nozzle inner end face 11 ... Fuel injection hole 13 ... Recess 15 ... Annular step portion 16 ... Valve portion 16a ... Sealing surface 16b ... Valve tip end surface 18 ... Valve body 25 ... Space 50a ... Intake port I ... -Fuel injection valve F-Fuel spray foam L-Conical surface bus extension S constituting the valve seat-Fuel flow Y-Valve seat and Nozzle center line D1 ··· Valve seat effective diameter D3 · · · Conical recess small diameter diameter E · Engine H · Height from valve seat member front end surface to valve seat The

Claims (2)

The valve seat member (3) having an annular valve seat (8), which is configured by a conical surface having a small diameter toward the front of the fuel injection valve (I) and on which the valve body (18) can be opened and closed, A nozzle (10) having a plurality of fuel injection holes (11) located on the downstream side of the valve seat (8) and arranged around the center line (Y) of the valve seat (8) is connected to the valve seat member ( 3), and a recess (13) for receiving the nozzle (10) is provided on the front end surface of the valve seat member (3), and each of the fuel injection holes (10) of the nozzle (10) is provided. 11), when the valve body (18) is opened, the main flow (S) of the fuel that has passed between the valve body (18) and the valve seat (8) is formed in each of the fuel injection holes (11). It is formed so as to directly collide with the inner surface, and the injected fuel from the fuel injection hole (11) is supplied to the intake port (50a) of the engine (E). A fuel injection valve which is adapted,
A tip surface (16b) on the tip side of the annular sealing surface (16a) seated on the valve seat (8) of the valve body (18), and the nozzle (10) facing the tip surface (16b) The inner end surface (10a) of each of these is constituted by a conical surface or a spherical surface having a small diameter toward the front of the fuel injection valve (I) and extending to the front of the fuel injection valve (I) from the fuel injection hole (11). In addition, an annular step (15) is formed between the inner end face (10a) of the nozzle (10) and the valve seat (8) to avoid mutual contact between the valve body (18) and the nozzle (10). Then, a space (25) is formed between the tip end face (16b) of the valve bodies (18) and the inner end face (10a) of the nozzle (10),
Each fuel injection hole (11) opens to the inner end surface (10a) of the nozzle (10) on the inner peripheral side of the annular step portion (15), and is an extension of the bus bar of the valve seat (8) (L) is arranged so as to intersect with the inner surface of each fuel injection hole (11),
The inner peripheral surface of the recess (13) that receives the nozzle (10) exhibits a Coanda effect on the conical spray foam (F) formed by the fuel injected from the fuel injection holes (11). Thus, the spray foam (F) is conically shaped to expand toward the front end surface of the valve seat member (3) so as to be directed downstream of the intake port (50a) of the engine (E) without disturbing the spray foam (F). And forming a diameter (D3) of a circle formed by the intersection of the virtual extension surface of the inner peripheral surface of the recess (13) and the virtual extension surface of the outer end surface of the nozzle (10 ) with the valve seat ( A fuel injection valve characterized in that it is set smaller than the effective diameter (D1) of 8). The fuel injection valve according to claim 1, wherein
A fuel injection valve characterized in that a height (H) from the front end face of the valve seat member (3) to the valve seat (8) is set to 1 mm or more.

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