JP2015078603A - Fuel injection valve - Google Patents

Abstract

The present invention achieves both atomization of fuel spray and suppression of fuel adhesion to the inner wall surface of an intake port by coexistence of atomization of injected fuel and narrow angle and high penetration of the spray shape. It is intended.
When each nozzle hole 5 is projected perpendicularly to a plane orthogonal to a valve seat axis 3c, the nozzle axis centered from the inlet center of the nozzle hole 5 to the outlet center of the nozzle hole 5 is a valve seat. An inward angle β is inclined in the direction of the central axis 21a of the collective spray with respect to the radial straight line 19 from the axis 3c toward the inlet center. Moreover, in each nozzle hole group 5a, the inward angle β1 of the central nozzle hole 5-1 arranged at the central part of the nozzle hole group 5a is equal to the end nozzle holes 5- arranged at both ends of the nozzle hole group 5a. 2 is smaller than the inward angle β2. Further, the diameter of the central injection hole 5-1 is larger than the diameter of the end injection hole 5-2.
[Selection] Figure 1

Description

  The present invention relates to a fuel injection valve used for supplying fuel to an internal combustion engine of an automobile, and more particularly to a fuel injection valve that achieves both atomization promotion in spray characteristics and narrow angle and high penetration of the spray shape. Is.

  In recent automobile gasoline internal combustion engines, one fuel injection valve is mounted per cylinder in order to improve controllability of fuel supply into the cylinder. Further, in order to achieve both improved output and improved fuel efficiency, there are almost always two intake ports provided per cylinder. The fuel injection valve in this case is required to inject fuel in two directions toward the respective intake ports, and to suppress the adhesion of fuel spray to the inner wall surface of the intake port.

  On the other hand, atomization of fuel spray is also required to improve fuel consumption and reduce exhaust gas. As a means for atomization, it is effective to use a wide-angle spray (that is, a low penetration spray). However, in order to suppress the fuel spray adhering to the intake port, it is necessary to use a narrow-angle spray (that is, a high penetration spray). Therefore, the atomization and the narrow-angle / high-penetration spray can be achieved only by operating the spray angle. It is difficult to balance.

  On the other hand, in the conventional fuel injection valve, the ratio of the injection hole length L to the injection hole diameter D (the injection hole L / D) is changed for each injection hole, thereby wide-angle / low penetration spray and narrow-angle / high penetration. A collective spray in which the spray is mixed is formed. In addition, the narrow-angle and high penetration spray that is aimed at the cylinder center side of the intake valve (however, the particle size is deteriorated), the wide-angle and low-angle that is aimed at the cylinder outer periphery to surround the narrow-angle and high penetration spray. By suppressing the dispersion of penetration spray (particle size is improved), spray adhesion to the inner wall surface of the intake port on the cylinder outer periphery side is suppressed (for example, see Patent Documents 1 to 3).

  In another conventional fuel injection valve, a plurality of nozzle holes are divided into two groups of nozzle holes with a plane including the valve hole axis of the valve seat member as a boundary, and a fuel diffusion chamber downstream of the valve seat member Is arranged. Further, the interval between the two groups of nozzle holes is made larger than the distance between the nozzle holes in each nozzle hole group. Further, the diameter of the central nozzle hole in each nozzle hole group is larger than the diameter of the nozzle holes on both sides thereof. Furthermore, the total area of the central nozzle hole is smaller than the total area of the nozzle holes on both sides.

  With such a configuration, a spray with a sharp top-to-bottom contour and high penetration is realized, and the spray adhesion to the top and bottom intake port inner wall surface is suppressed on the outer peripheral side of the cylinder (for example, Patent Documents) 4).

Japanese Patent Laid-Open No. 2005-23875 JP-A-2005-207291 JP 2009-79598 A Japanese Patent No. 4138778

  However, in the conventional fuel injection valves disclosed in Patent Documents 1 to 3, the traction effect of the narrow angle / high penetration spray suppresses the scattering of the wide angle / low penetration spray. Could not be sufficiently suppressed. Moreover, even if a certain degree of suppression effect is obtained, the effect is obtained only on the downstream side of the spray where the spray splitting progresses and the spray particle size and spray speed are small. In addition, the traction effect cannot be expected on the upstream side of the spray where the spray speed is high.

  On the other hand, in recent internal combustion engines of automobiles, the passage area of the intake port is minimized in order to enhance the intake tumble flow in the cylinder by increasing the intake flow velocity, and connects the tip of the fuel injection valve to the intake port. The area of the fuel spray passage is also minimized, and the gap between the spray and the inner wall surface of the spray passage is small on the upstream side of the spray.

  Therefore, with the conventional fuel injection valves disclosed in Patent Documents 1 to 3, it is difficult to suppress the adhesion of fuel spray to the inner wall surface of the spray passage. Moreover, since the inner wall surface of the spray passage is away from the cylinder and the wall surface temperature is low, there is a problem that if the fuel spray adheres to this, it is difficult to vaporize and the controllability of the fuel supply into the cylinder deteriorates. .

  In addition, in order to strengthen the intake tumble flow, the intake port is mostly curved in the vertical direction (vertical direction). In that case, in the vertical direction in the intake port, the intake port curved with the straight traveling spray It is difficult to secure a gap with the inner wall surface. Further, when fuel injection is performed in the intake stroke for the purpose of improving fuel efficiency, fuel spray is caused to flow by the intake air flow, so that the spray tends to adhere to the ceiling inner wall surface of the intake port.

  For this reason, when using the conventional fuel injection valves disclosed in Patent Documents 1 to 3 and injecting fuel in the intake stroke, the wide-angle, low penetration spray targeting the cylinder outer peripheral side is easily flowed into the intake flow, There was a problem that the spray easily adheres to the ceiling inner wall.

  On the other hand, in the conventional fuel injection valve shown in Patent Document 4, since the spray in the vertical direction is a high penetration spray, even when fuel is injected in the intake stroke, the fuel spray does not flow in the intake air flow. . In addition, since the low penetration spray sandwiched between the walls of the high penetration spray in the vertical direction is not caused to flow into the intake air flow, it is possible to suppress the fuel spray from adhering to the ceiling and bottom surface of the inner wall surface of the intake port.

  However, the fuel injected from the central injection hole diffuses in the injection direction due to the influence of the flow component in the radial direction in the fuel diffusion chamber, but the injection in the injection direction is caused by the narrow angle and high penetration spray on both sides. Since diffusion cannot be suppressed, there is a problem that fuel adhesion to the inner wall of the intake port in the injection direction cannot be suppressed.

  In addition, the total cross-sectional area of the central nozzle hole aimed at atomization is smaller than the two-sided nozzle hole, so there are more particles with a larger particle size than particles with a smaller particle size, and the overall particle size of the spray deteriorates. There was also a problem.

  The present invention has been made to solve the above-described problems, and by making the atomization of the fuel to be atomized promoted and achieving a narrow angle and high penetration of the spray shape, the atomization of the fuel spray and the intake air can be achieved. It aims at obtaining the fuel injection valve which can make fuel adhesion suppression to a port inner wall surface compatible.

  The fuel injection valve according to the present invention has a seat surface that is inclined so that the diameter is gradually reduced toward the downstream side, and a valve seat opening provided on the downstream side of the seat surface. A valve body that abuts against the valve seat and the seat surface to prevent fuel from flowing out from the valve seat opening, and that is separated from the seat surface to allow fuel outflow from the valve seat opening, and a downstream end surface of the valve seat And a nozzle hole plate having a plurality of nozzle holes for injecting fuel that has flowed out of the valve seat opening to the outside, the nozzle hole plate being a virtual conical surface extending the seat surface downstream And the upstream end surface of the nozzle hole plate are arranged so as to intersect to form a virtual circle, and the nozzle hole is arranged on the valve seat axis side with respect to the valve seat opening which is the minimum inner diameter of the valve seat, In addition, two nozzle hole groups are formed so as to form a collective spray in two directions. When projected perpendicularly to a plane perpendicular to the axis, the outlet center of the nozzle hole is located at a position away from the valve seat axis with respect to the inlet center, and the nozzle hole axis from the inlet center toward the outlet center The center is inclined in the direction of the central axis of the collective spray with respect to a radial straight line from the valve seat axis toward the inlet center, and when the inclination angle is an inward angle β, the center of each nozzle hole group The inward angle β1 of the central nozzle hole, which is the nozzle hole arranged in the portion, is smaller than the inward angle β2 of the end nozzle holes, which are the nozzle holes arranged at both ends of each nozzle hole group, The diameter of the central nozzle hole is larger than the diameter of the nozzle hole arranged at least on the ceiling inner wall surface side of the intake port among the end nozzle holes.

  According to the fuel injection valve of the present invention, when the nozzle hole is projected perpendicularly to a plane orthogonal to the valve seat axis, the outlet center of the nozzle hole is located away from the valve seat axis with respect to the inlet center. The nozzle hole center from the inlet center to the outlet center is inclined in the direction of the central axis of the collective spray with respect to the radial straight line from the valve seat axis to the inlet center. Is an inward angle β, the inward angle β1 of the central nozzle hole, which is a nozzle hole arranged at the center of each nozzle hole group, is the end of the nozzle hole arranged at both ends of each nozzle hole group The inner nozzle hole is smaller than the inward angle β2 and the diameter of the central nozzle hole is larger than the diameter of the nozzle hole arranged at least on the ceiling inner wall surface of the intake port. Atomization of fuel spray by promoting the atomization of the fuel to be used and the narrow angle and high penetration of the spray shape It is possible to achieve both fuel adhesion inhibition of the intake port wall.

It is sectional drawing in alignment with the axis line of the fuel injection valve by Embodiment 1 of this invention. It is a figure which combines and shows the enlarged view of the valve seat of FIG. 1, a nozzle hole plate, and a ball | bowl, and the top view which shows the center part of a nozzle hole plate. It is sectional drawing which follows the III-III line of FIG. It is sectional drawing which follows the IV-IV line of FIG. It is a figure which combines and shows the enlarged view of the valve seat of FIG. 1, a nozzle hole plate, and a ball | bowl, and the top view which shows the state of the spray from each nozzle hole. It is a graph which shows the time change of the spray particle size at the time of the fuel injection by the fuel injection valve of FIG. It is sectional drawing which shows the state which attached the fuel injection valve by Embodiment 2 of this invention to the intake port. It is the figure which looked at the nozzle hole plate of FIG. 7 along the arrow VIII direction from the downstream of a fuel injection valve. It is a figure which combines and shows the principal part sectional drawing of the fuel injection valve by Embodiment 3 of this invention, and the top view which shows the center part of a nozzle hole plate. It is sectional drawing which follows the XX line of FIG. It is sectional drawing which follows the XI-XI line of FIG. It is sectional drawing which shows the state which attached the fuel injection valve by Embodiment 4 of this invention to the intake port. It is the figure which looked at the nozzle hole plate of FIG. 12 along the arrow XIII direction from the downstream of a fuel injection valve. It is sectional drawing which expands and shows the center injection hole of the fuel injection valve by Embodiment 5 of this invention. It is a figure which shows combining the principal part sectional drawing of the fuel injection valve by Embodiment 6 of this invention, the top view which shows the center part of a nozzle hole plate, and the state of the spray from each nozzle hole. It is a figure shown combining the principal part sectional view of the fuel injection valve by Embodiment 6 of this invention, and the top view which shows the center part of a nozzle hole plate. It is sectional drawing which follows the XVII-XVII line of FIG. It is sectional drawing which follows the XVIII-XVIII line of FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
1 is a cross-sectional view taken along the axis of a fuel injection valve according to Embodiment 1 of the present invention. Fuel flows downward from the upper end of the fuel injection valve of FIG. In the figure, a cylindrical fixed iron core 2 is fixed to the upper end of the magnetic pipe 1. The magnetic pipe 1 and the fixed iron core 2 are arranged coaxially. Further, the magnetic pipe 1 is press-fitted and welded to the downstream end portion of the fixed iron core 2.

  A valve seat 3 and an injection hole plate 4 are fixed to the lower end portion in the magnetic pipe 1. The nozzle hole plate 4 is provided with a plurality of nozzle holes 5 for injecting fuel. The nozzle hole 5 penetrates the nozzle hole plate 4 in the thickness direction.

  The nozzle hole plate 4 is fixed to the magnetic pipe 1 by the second welded portion 4b after being inserted into the magnetic pipe 1 while being fixed to the downstream end face of the valve seat 3 by the first welded portion 4a. Has been.

  In the magnetic pipe 1, there are a ball 6 as a valve body, a needle pipe 7 welded and fixed to the ball 6, and an armature fixed to the upstream end (the end opposite to the ball 6) of the needle pipe 7. (Movable iron core) 8 is inserted. The amateur 8 is press-fitted into the upstream end portion of the needle pipe 7 and welded.

  The amateur 8 can slide in the axial direction within the magnetic pipe 1. On the inner peripheral surface of the magnetic pipe 1, a guide portion 1 a that guides the sliding of the armature 8 is provided. As the amateur 8 slides, the needle pipe 7 and the armature 8 also move together in the axial direction. Thereby, the ball 6 is seated / separated from the valve seat 3. Further, the upper end surface of the armature 8 is brought into contact with and separated from the lower end surface of the fixed iron core 2. A chamfered portion 6 a is provided on the outer periphery of the ball 6.

  A compression spring 9 that presses the needle pipe 7 in the direction of pressing the ball 6 against the valve seat 3 is inserted into the fixed iron core 2. An adjuster 10 for adjusting the load of the compression spring 9 is fixed in the fixed iron core 2. Further, a filter 11 is inserted into the upper end portion of the fixed iron core 2 serving as a fuel introduction portion.

  An electromagnetic coil 12 is fixed to the outer periphery of the downstream end (the armature 8 side end) of the fixed iron core 2. The electromagnetic coil 12 has a resin bobbin 13 and a coil body 14 wound around the outer periphery thereof. Between the magnetic pipe 1 and the fixed iron core 2, a metal plate (magnetic circuit constituent member) 15 which is a yoke portion of the magnetic circuit is fixed by welding.

  The magnetic pipe 1, the fixed iron core 2, the electromagnetic coil 12, and the metal plate 15 are integrally formed in a resin housing 16. The resin housing 16 is provided with a connector portion 16a. A terminal 17 that is electrically connected to the coil body 14 is drawn into the connector portion 16a.

  2 is an enlarged view of the valve seat 3, the nozzle hole plate 4 and the ball 6 of FIG. 1, and a plan view showing the central part of the nozzle hole plate 4 (the part exposed to the fuel flow path is indicated by the arrow II from the ball 6 side). FIG. 3 is a sectional view taken along line III-III in FIG. 2, and FIG. 4 is a sectional view taken along line IV-IV in FIG.

  In the valve seat 3, a seat surface 3a to which the ball 6 is brought into contact with and separated from is provided. The seat surface 3a is inclined so that its diameter is gradually reduced toward the downstream side. A circular valve seat opening 3b facing the nozzle hole plate 4 is provided at the center of the downstream end of the valve seat 3 on the downstream side of the seat surface 3a.

  The ball 6 abuts against the seat surface 3a to prevent the fuel from flowing out from the valve seat opening 3b, and is separated from the seat surface 3a to allow the fuel to flow out from the valve seat opening 3b. The nozzle hole plate 4 is arranged such that a virtual conical surface 18a that extends the sheet surface 3a downstream and an upstream end surface of the nozzle hole plate 4 intersect to form a virtual circle 18b.

  Each nozzle hole 5 has a valve seat formed on the valve seat axis 3c side with respect to the valve seat opening 3b which is the minimum inner diameter portion of the valve seat 3 when the nozzle hole plate 4 is viewed along the valve seat axis 3c. It arrange | positions on one circle | round | yen (injection hole arrangement | positioning circle) 18c centering on an axial center.

  Further, the nozzle hole 5 forms two nozzle hole groups 5a so as to form a collective spray 21 (FIG. 5) in two directions. In the plan view of the nozzle hole plate 4 in FIG. 2, one nozzle hole group 5 a is constituted by the four right nozzle holes 5, and the other nozzle hole group 5 a is constituted by the four left nozzle holes 5.

  Each nozzle hole group 5a includes a plurality (two in FIG. 2) of central nozzle holes 5-1 arranged at the center in the circumferential direction of the circle 18c in each nozzle hole group 5a, and the circumference of the circle 18c. It comprises a plurality of (two in FIG. 2) end nozzle holes 5-2 disposed at both ends in the direction.

  When each nozzle hole 5 is projected perpendicularly to a plane perpendicular to the valve seat axis 3c, the outlet center 5c of the nozzle hole is positioned away from the valve seat axis 3c with respect to the inlet center 5b of the nozzle hole 5. Has been placed. That is, the nozzle hole 5 is inclined so as to advance outward in the radial direction of the nozzle hole plate 4 as it goes downstream.

  When each nozzle hole 5 is projected perpendicularly to a plane orthogonal to the valve seat axis 3c, the nozzle axis 5d from the inlet center 5b of the nozzle hole 5 toward the outlet center 5c of the nozzle hole 5 An inward angle β is inclined in the direction of the central axis 21a of the collective spray 21 with respect to the radial straight line 19 from the seat axis 3c toward the inlet center 5b. Furthermore, in each nozzle hole group 5a, the inward angle β1 of the central nozzle hole 5-1 is smaller than the inward angle β2 of the end nozzle hole 5-2.

  Furthermore, the diameter of the central injection hole 5-1 is larger than the diameter of the end injection hole 5-2. That is, the diameter of the end nozzle hole 5-2 is smaller than the diameter of the central nozzle hole 5-1. In this example, the diameter of the central injection hole 5-1 is larger than the diameters of all the end injection holes 5-2. 3 shows a cross section along the injection hole axis 5d of the central injection hole 5-1, and FIG. 4 shows a cross section along the injection hole axis 5d of the end injection hole 5-2.

  At the center of the nozzle hole plate 4, a convex portion 4 c that is curved so as to protrude to the downstream side in parallel (or substantially parallel) to the tip portion of the ball 6 is provided. A flat nozzle hole plate flat portion 4d is provided around the convex portion 4c. The nozzle hole 5 is provided in the nozzle hole plate flat part 4d.

  Next, the operation of the fuel injection valve will be described. When an operation signal is sent from the engine control device to the drive circuit of the fuel injection valve, a current flows through the electromagnetic coil 12 via the terminal 17, and the armature 8, the fixed iron core 2, the metal plate 15, and the magnetic pipe 1 are configured. Magnetic flux is generated in the magnetic circuit.

  Thereby, the armature 8 is attracted | sucked to the fixed iron core 2 side, and the armature 8, the needle pipe 7, and the ball | bowl 6 which are integral structures move upward of FIG. When the ball 6 is separated from the valve seat 3 and a gap is generated between the ball 6 and the valve seat 3, the fuel passes through the gap between the chamfered portion 6 a of the ball 6 and the valve seat 3 and passes through the nozzle hole 5. It is injected into the engine intake port.

  Next, when an operation stop signal is sent from the engine control device to the drive circuit of the fuel injection valve, the energization to the electromagnetic coil 12 is stopped, the magnetic flux in the magnetic circuit is reduced, and the spring force of the compression spring 9 The amateur 8, the needle pipe 7 and the ball 6 move downward in FIG. Thereby, the clearance gap between the ball | bowl 6 and the valve seat 3 is closed, and fuel injection is complete | finished.

  In such a fuel injection valve, when the fuel flow toward the inlet of the nozzle hole 5 at the time of fuel injection is projected perpendicularly to a plane perpendicular to the valve seat axis 3c, the inlet center 5b of the nozzle hole 5 from the seat surface 3a. As shown in the plan view of FIG. 2, the main flow of the fuel flow directly toward is a flow 20a toward the valve seat axis 3c. On the other hand, the nozzle hole 5 is inclined in a direction away from the valve seat axis 3c as it goes downstream. For this reason, the fuel flow is separated at the inlet of the nozzle hole 5, and after the fuel collides with the valve seat axis 3 c side of the inner wall of the nozzle hole 5, the liquid film of the fuel is thinly spread along the inner wall of the nozzle hole 5. A stream 20d is formed.

  In particular, since the central injection hole 5-1 having a small inward angle β1 is in a direction almost directly opposite to the main flow 20a of the fuel in the above plane, the fuel liquid after the fuel collides with the inner wall as shown in FIG. The flow 20d in which the membrane is spread thinly along the inner wall is further strengthened. Further, since the central nozzle hole 5-1 has a large diameter, the liquid film can be spread more thinly on the inner wall.

  Therefore, the fuel injected from the central injection hole 5-1 can be efficiently made into a thin film and promote atomization. As for the spray shape, by reducing the nozzle hole L / D (for example, the nozzle hole L / D <1), it becomes a wide angle / low penetration spray that diffuses in a direction (side surface direction) perpendicular to the injection direction. .

  On the other hand, the end injection hole 5-2 having a large inward angle β2 does not face the main fuel flow 20a in the above-described plane, so that liquid film formation on the inner wall is weakened as shown in FIG. Further, since the end nozzle hole 5-2 has a small diameter, by increasing the nozzle hole L / D (for example, the nozzle hole L / D> 1), the end nozzle hole 5-2 flows while filling the nozzle hole 5-2 and exits. It is sprayed as a solid spray, and the spray shape becomes a narrow angle and high penetration.

  FIG. 5 is an enlarged view of the valve seat 3, the nozzle hole plate 4 and the ball 6 in FIG. 1, and a plan view showing the state of spraying from each nozzle hole 5 (viewed along the arrow V from the ball 6 side). It is a figure shown combining.

  As shown in FIG. 5, the narrow-angle / high penetration spray 21c from the end nozzle hole 5-2 serves as a wall where the sprays injected from the nozzle holes 5 interfere with each other, and the central nozzle hole 5- It is possible to prevent the wide angle / low penetration spray (atomization spray) 21b from 1 from being excessively diffused in the side surface direction. On the other hand, since the wide-angle / low-penetration spray 21b from the central nozzle hole 5-1 does not diffuse too much in the injection direction (front direction), it becomes a narrow-angle spray in both the side direction and the front direction, toward the inner wall of the intake port. The adhesion of the fuel spray can be suppressed.

  Further, in the first embodiment, the sum of the channel areas of the central nozzle hole 5-1 is larger than the sum of the channel areas of the end nozzle holes 5-2. Therefore, the narrow angle / high penetration with a low atomization degree. The amount of the wide-angle / low-penetration spray 21b having a higher atomization degree than the spray 21c is increased, and the average particle diameter of the entire spray can be reduced.

  Furthermore, at the start of injection, fuel in a space (dead volume) surrounded by the inner wall of the valve seat 3 downstream of the seat surface 3a, the upstream end surface of the nozzle hole plate 4, and the tip of the ball 6 is injected. Since it is discharged from the hole 5, the injection speed is lower than that at the time of steady injection after completion of the valve opening operation of the ball 6. For this reason, the initial spray at the start of injection tends to have a larger spray particle size than at the time of steady injection. It is in.

  On the other hand, in the first embodiment, the virtual conical surface 18a extending the downstream side of the seat surface 3a and the upstream end surface of the nozzle hole plate 4 intersect to form a virtual circle 18b. The dead volume is made small by arranging. For this reason, the injection amount of the initial spray having a large particle size can be reduced, and as shown in FIG. 6, the particle size of the entire spray including the initial spray and the steady spray can be reduced.

  In addition, since the dead volume is small, the amount of fuel evaporation in the dead volume during injection suspension under high temperature negative pressure is reduced, and the change in injection amount (static flow rate / dynamic flow rate) due to changes in temperature and atmospheric pressure is reduced. can do.

  Further, in the fuel flow downstream from the seat surface 3a, as shown in the plan view of FIG. 2, in addition to the main flow 20a of the fuel flowing directly from the seat surface 3a to the inlet of the nozzle hole 5, the fuel passing between the nozzle holes 5 is used. Stream 20b is included. Further, the flow 20 b collides with the fuel flowing from the opposite side at the center of the nozzle hole plate 4, and becomes a U-turn flow 20 c toward the nozzle hole 5.

  In the first embodiment, since the convex portion 4c that is curved so as to protrude downstream in parallel to the tip portion of the ball 6 is provided at the center of the nozzle hole plate 4, as shown in FIG. The flow 20c becomes a flow along the convex part 4c, and it is difficult to flow into the nozzle hole 5 provided in the nozzle hole plate flat part 4d outside the convex part 4c.

  On the other hand, the main flow 20a of the fuel sinks under the U-turn flow 20c and easily collides with the upstream side of the inner wall of the nozzle hole 5. Thereby, the effective length of the inner wall of the injection hole 5 necessary for expanding the liquid film can be increased, the fuel can be efficiently thinned, and atomization can be promoted.

  Further, as shown in the cross-sectional view of FIG. 2, the valve seat shaft on the seat surface 3 a and the upstream end surface of the nozzle hole plate 4 while avoiding interference between the tip of the ball 6 and the nozzle hole plate 4 at the time of valve closing. The distance from the vicinity of the center 3c can be shortened, and the virtual circle 18b can be enlarged.

  Thereby, the inlet center 5b of the nozzle hole 5 arranged in the nozzle hole plate flat part 4d outside the convex part 4c can be arranged inside the virtual circle 18b, and the liquid film is formed along the inner wall of the nozzle hole 5. Can be strengthened. Therefore, the fuel can be thinned efficiently and atomization can be promoted.

  Furthermore, the dead volume can be further reduced while avoiding interference between the tip of the ball 6 and the nozzle hole plate 4 when the valve is closed, so that the injection amount of the initial spray having a large particle size can be further reduced, and the initial spray can be reduced. And the particle size of the entire spray combined with the steady spray can be further reduced.

Embodiment 2. FIG.
7 is a cross-sectional view showing a state in which the fuel injection valve according to Embodiment 2 of the present invention is attached to the intake port 22. FIG. 8 shows the injection hole plate 4 of FIG. It is the figure seen along the direction.

  In the case of fuel injection in the intake stroke, fuel spray is caused to flow by the intake air flow, so that there is a problem that the spray tends to adhere to the ceiling inner wall surface 22a of the intake port 22 and the fuel spray passage 22c.

  On the other hand, in Embodiment 2, the diameter of the nozzle hole 5 arranged on the ceiling inner wall surface 22a side in the end nozzle hole 5-2 is reduced, and arranged on the bottom inner wall surface 22b side of the intake port 22. The diameter of the nozzle hole 5 is increased. That is, the diameter of the end nozzle hole 5-2 disposed on the bottom inner wall surface 22b side is larger than the diameter of the end nozzle hole 5-2 disposed on the ceiling inner wall surface 22a side.

  In this example, the diameter of the end injection hole 5-2 arranged on the bottom inner wall surface 22b side is the same as or substantially the same as the diameter of the central injection hole 5-1. Other configurations are the same as those in the first embodiment.

  As a result, even in the case of injection in the intake stroke, spraying toward the center and bottom inner wall surface 22b of the spray is suppressed at a wide angle and low penetration while suppressing the spray adhesion to the ceiling inner wall surface 22a and the fuel spray passage 22c. The atomization spray can be used to promote atomization of the entire spray. At this time, since the spray in the direction of the bottom inner wall surface 22b is a low penetration atomization spray, the fuel spray flows in the intake air flow in the intake stroke injection, and the spray adhesion to the bottom inner wall surface 22b is suppressed.

  Therefore, the atomized spray can be directly entered into the cylinder, and the spray can be made suitable for the intake stroke injection for the purpose of improving the fuel consumption.

Embodiment 3 FIG.
Next, FIG. 9 is a cross-sectional view of the main part of the fuel injection valve according to Embodiment 3 of the present invention, and a plan view showing the central part of the injection hole plate 4 (the part exposed to the fuel flow path from the ball 6 side) FIG. 10 is a cross-sectional view taken along line XX in FIG. 9, and FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 9.

  In the third embodiment, each central nozzle hole 5-1 is formed so as to partially overlap the nozzle hole main body 5e similar to the central nozzle hole 5-1 of the first embodiment and the outlet portion of the nozzle hole main body 5e. And an enlarged diameter portion (large diameter portion) 5h. The nozzle hole body 5e and the enlarged diameter portion 5h correspond one-to-one.

  Each of the enlarged diameter portions 5h has a cylindrical shape centered on an axis perpendicular to the nozzle hole plate 4 (parallel to the valve seat axis 3c). Further, the center 5i of the enlarged diameter portion 5h is disposed at a position farther from the valve seat axis 3c than the outlet center 5c of the nozzle hole body 5e. Configurations other than the central nozzle hole 5-1 are the same as those in the first or second embodiment.

  In such a fuel injection valve, as the fuel flows from the nozzle hole body 5e into the enlarged diameter portion 5h, the liquid film is further spread thinly along the curvature of the inner wall of the enlarged diameter portion 5h, as shown in FIG. While further promoting atomization, spray adhesion to the inner wall surface of the intake port can be suppressed as in the first embodiment.

Embodiment 4 FIG.
12 is a cross-sectional view showing a state in which the fuel injection valve according to Embodiment 4 of the present invention is attached to the intake port 22, and FIG. 13 shows the injection hole plate 4 of FIG. 12 from the downstream side of the fuel injection valve by the arrow XIII. It is the figure seen along the direction.

  In the fourth embodiment, the enlarged diameter portion 5h is provided at the outlet of the nozzle hole 5 arranged on the bottom inner wall surface 22b side of the intake port 22 in the end nozzle hole 5-2. Other configurations are the same as those of the third embodiment.

  In such a fuel injection valve, since the enlarged diameter portion 5h is provided in the end injection hole 5-2 arranged on the bottom inner wall surface 22b side, as in the second embodiment, the intake stroke for the purpose of improving the fuel efficiency. A spray suitable for injection can be obtained.

Embodiment 5 FIG.
Next, FIG. 14 is an enlarged sectional view showing the central injection hole 5-1 of the fuel injection valve according to Embodiment 5 of the present invention. In the fifth embodiment, in the flow path of the central nozzle hole 5-1, a cylindrical portion 5j having a minimum cross-sectional area is provided between the inlet and the outlet of the nozzle hole body 5e. Other configurations are the same as those of the third embodiment.

  In such a fuel injection valve, since the flow rate of the fuel in the central nozzle hole 5-1 is determined by the cross-sectional area of the cylindrical portion 5j, the flow rate variation due to the variation in the positions of the nozzle hole body 5e and the enlarged diameter portion 5h is suppressed. Can do.

In addition, the cylindrical portion 5j may be provided in the nozzle hole body 5e of the end nozzle hole 5-2 on the bottom inner wall surface 22b side in the fourth embodiment. That is, Embodiments 4 and 5 may be combined.
In the third to fifth embodiments, the diameter of the central injection hole 5-1 does not necessarily need to be larger than the diameter of the end injection hole 5-2.

Embodiment 6 FIG.
Next, FIG. 15 is a cross-sectional view of the main part of a fuel injection valve according to Embodiment 6 of the present invention, and a plan view showing the central portion of the injection hole plate 4 (the portion exposed to the fuel flow path from the ball 6 side) FIG. 5 is a view showing a combination of the state of spraying from each nozzle hole 5 and a view seen along the arrow XV.

  In Embodiment 6, the interval γ3 between the two groups of nozzle holes 5a is smaller than the inter-hole distances γ1 and γ2 in each nozzle hole group 5a. Other configurations are the same as those in the first, second, third, fourth or fifth embodiment.

  In such a fuel injection valve, since the interval γ3 of the nozzle hole group 5a is smaller than the inter-hole distances γ1, γ2 in each nozzle hole group 5a, the inter-hole distances γ1, γ2 can be increased, Immediately after that, at the stage of the liquid film before spray splitting, it is possible to suppress interference between the liquid films ejected from the respective nozzle holes 5.

  In addition, in the plane orthogonal to the valve seat axis 3c, the angle β2 formed by the direction of the nozzle hole axis 5d of the end nozzle hole 5-2 and the main flow 20a of the fuel is further increased. Liquid film formation is further weakened, and narrow-angle, high-penetration spray can be further enhanced.

Embodiment 7 FIG.
Next, FIG. 16 is a cross-sectional view of an essential part of a fuel injection valve according to Embodiment 6 of the present invention, and a plan view showing a central portion of the injection hole plate 4 (the portion exposed to the fuel flow path from the ball 6 side) FIG. 17 is a sectional view taken along line XVII-XVII in FIG. 16, and FIG. 18 is a sectional view taken along line XVIII-XVIII in FIG.

  In the first embodiment, the convex portion 4c is provided at the center of the nozzle hole plate 4, but in the seventh embodiment, the center of the nozzle hole plate 4 is flat. In the seventh embodiment, a ball flat portion (valve flat portion) 6 b parallel to (or substantially parallel to) the nozzle hole plate 4 is provided at the tip of the ball 6.

  The ball flat portion 6 b faces the center of the upstream end surface of the nozzle hole plate 4. When projected perpendicularly to a plane orthogonal to the valve seat axis 3 c, the ball flat portion 6 b is provided on the inner diameter side with respect to the inlets of all the nozzle holes 5. Other configurations are the same as those in the first, second, third, fourth, fifth, or sixth embodiment.

  In the plan view of FIG. 16, the flow passage cross-sectional area of the fuel flow 20b passing between the nozzle holes 5 toward the center of the nozzle hole plate 4 is rapidly reduced when passing through the portion facing the ball flat portion 6b. . For this reason, the pressure loss increases, and the velocity of the flow 20b decreases at the portion facing the ball flat portion 6b.

  Along with this, the speed of the U-turn flow 20c also decreases, so that the U-turn flow 20c hardly flows into the nozzle hole 5. Therefore, as shown in FIG. 17, at the inlet of the nozzle hole 5, the main flow 20 a of fuel can overcome the U-turn flow 20 c and collide with the upstream side of the inner wall of the nozzle hole 5.

  As a result, the effective length of the inner wall of the injection hole 5 necessary for widening the liquid film can be increased, the fuel can be efficiently thinned, and atomization can be further promoted.

  Further, as shown in the sectional view of FIG. 16, the valve seat between the seat surface 3 a and the upstream end surface of the nozzle hole plate 4 while avoiding interference between the tip of the ball 6 and the nozzle hole plate 4 when the valve is closed. The distance in the direction of the axis 3c can be shortened. Thereby, the virtual circle 18b can be enlarged and the inlet center 5b of the nozzle hole 5 can be arranged inside the virtual circle 18b. Accordingly, the flow for expanding the liquid film along the inner wall of the nozzle hole 5 is further strengthened, whereby the fuel can be efficiently thinned and atomization can be promoted.

  Furthermore, the dead volume can be further reduced while avoiding interference between the tip of the ball 6 and the nozzle hole plate 4 when the valve is closed. Thereby, the injection amount of the initial spray having a large particle size can be further reduced, and the particle size of the entire spray including the initial spray and the steady spray can be further reduced.

  3 Valve seat, 3a Seat surface, 3b Valve seat opening, 3c Valve seat axis, 4 Injection hole plate, 4c Convex part, 4d Injection hole plate flat part, 5 Injection hole, 5a Injection hole group, 5b Inlet center, 5c Outlet Center, 5d Injection hole axis, 5e Injection hole body, 5h Expanding part, 5i Center of expanding part, 5j Cylindrical part, 5-1 Central injection hole, 5-2 End injection hole, 6 balls (valve) 6b Ball flat part (valve flat part), 18a virtual conical surface, 18b virtual circle, 19 radial straight line, 21 collective spray, 21a central axis of collective spray, 22 intake port, 22a ceiling inner wall surface, 22b bottom inner wall surface .

Claims (10)

A valve seat having a seat surface inclined such that the diameter is gradually reduced toward the downstream side, and a valve seat opening provided on the downstream side of the seat surface;
A valve body that abuts against the seat surface to prevent fuel from flowing out of the valve seat opening and is separated from the seat surface to allow fuel outflow from the valve seat opening; and downstream of the valve seat An injection hole plate that is fixed to a side end surface and has a plurality of injection holes for injecting fuel that has flowed out of the valve seat opening to the outside;
The nozzle hole plate is arranged so that a virtual conical surface extending the sheet surface downstream and an upstream end surface of the nozzle hole plate intersect to form a virtual circle,
The nozzle hole is arranged on the valve seat axial side from the valve seat opening which is the minimum inner diameter of the valve seat, and forms two nozzle hole groups so as to form a collective spray in two directions,
When the nozzle hole is projected perpendicularly to a plane orthogonal to the valve seat axis, the outlet center of the nozzle hole is disposed at a position away from the valve seat axis with respect to the inlet center,
The injection hole axis from the inlet center to the outlet center is inclined in the direction of the central axis of the collective spray with respect to a radial straight line from the valve seat axis to the inlet center,
When the inclination angle is an inward angle β, the inward angle β1 of the central nozzle hole, which is the nozzle hole arranged in the central part of each nozzle hole group, is arranged at both ends of each nozzle hole group. The inward angle β2 of the end nozzle hole, which is the nozzle hole,
The fuel injection valve according to claim 1, wherein a diameter of the central injection hole is larger than a diameter of at least the injection hole disposed on the ceiling inner wall surface side of the intake port among the end injection holes.   The fuel injection valve according to claim 1, wherein the diameter of the central injection hole is larger than the diameters of all the end injection holes.   The diameter of the end nozzle hole disposed on the bottom inner wall surface side of the intake port is larger than the diameter of the end nozzle hole disposed on the ceiling inner wall surface side of the intake port. The fuel injection valve according to 1. A valve seat having a seat surface inclined such that the diameter is gradually reduced toward the downstream side, and a valve seat opening provided on the downstream side of the seat surface;
A valve body that abuts against the seat surface to prevent fuel from flowing out of the valve seat opening and is separated from the seat surface to allow fuel outflow from the valve seat opening; and downstream of the valve seat An injection hole plate that is fixed to a side end surface and has a plurality of injection holes for injecting fuel that has flowed out of the valve seat opening to the outside;
The nozzle hole plate is arranged so that a virtual conical surface extending the sheet surface downstream and an upstream end surface of the nozzle hole plate intersect to form a virtual circle,
The nozzle hole is arranged on the valve seat axial side from the valve seat opening which is the minimum inner diameter of the valve seat, and forms two nozzle hole groups so as to form a collective spray in two directions,
When the nozzle hole is projected perpendicularly to a plane orthogonal to the valve seat axis, the outlet center of the nozzle hole is disposed at a position away from the valve seat axis with respect to the inlet center,
The injection hole axis from the inlet center to the outlet center is inclined in the direction of the central axis of the collective spray with respect to a radial straight line from the valve seat axis to the inlet center,
When the inclination angle is an inward angle β, the inward angle β1 of the central nozzle hole, which is the nozzle hole arranged in the central part of each nozzle hole group, is arranged at both ends of each nozzle hole group. The inward angle β2 of the end nozzle hole, which is the nozzle hole,
The central nozzle hole has a nozzle hole body and a diameter-expanded part formed to partially overlap the outlet of the nozzle hole body,
The diameter of the expanded portion is larger than the diameter of the nozzle hole body,
The fuel injection valve characterized in that the center of the diameter-expanded portion is disposed at a position farther from the valve seat axis than the center of the outlet of the nozzle hole body.   5. The fuel injection valve according to claim 4, wherein the enlarged-diameter portion is also provided at an outlet of the injection hole arranged on the bottom inner wall surface side of the intake port among the end injection holes.   5. The cylindrical portion having a minimum cross-sectional area is provided between an inlet and an outlet of the nozzle hole body in the nozzle hole passage provided with the enlarged diameter portion. Item 6. The fuel injection valve according to Item 5.   The fuel injection valve according to any one of claims 1 to 6, wherein an interval between the two groups of the nozzle hole groups is smaller than a distance between the nozzle holes in the nozzle hole group.   The sum total of the flow-path area of the said center nozzle hole is larger than the sum total of the flow-path area of the said end part nozzle hole, The any one of Claim 1 to 7 characterized by the above-mentioned. Fuel injection valve. The nozzle hole plate is provided with a convex portion projecting downstream in order to avoid interference with the tip of the valve body when the valve is closed,
Around the projection of the nozzle hole plate, a flat nozzle hole plate flat part is provided,
The fuel injection valve according to any one of claims 1 to 8, wherein the nozzle hole is provided in a flat portion of the nozzle hole plate. In order to avoid interference with the nozzle hole plate when the valve is closed, a flat part parallel to or substantially parallel to the nozzle hole plate is provided at the tip of the valve body,
The flat portion is provided on an inner diameter side with respect to the inlet of the nozzle hole when projected perpendicularly to the plane. 9. Fuel injection valve.

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