JP2019002369A - Fuel injection valve - Google Patents

Abstract

To provide a fuel injection valve which can make fuel surely flow into an injection hole even immediately before a needle valve is seated.SOLUTION: In a fuel injection valve comprising a valve body 140 having a seat ring 144, a recess 145 and an injection hole 146 at a bottomed cylindrical bottom part, and a needle valve 150 having a valve seat 154 which can be seated to or separate from the seat ring, and a protrusive part 155 protruding to a bottom part inner wall side of the valve body in a region being an internal peripheral side with respect to the valve seat, and making fuel circulate into the injection hole from a clearance between the seat ring and the valve seat at valve-opening, the protrusive part is formed into a columnar shape, a columnar peripheral wall face is formed as a guide part 155a, and a virtual extension line L extending to the injection hole side from the guide part is set so as to enter a region of an inlet opening of the injection hole when the valve seat is seated on the seat ring on a virtual plane P including a cylinder axial line CL of the valve body and a center point HO of the inlet opening of the injection hole.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fuel injection valve that injects and supplies fuel to, for example, an internal combustion engine.

  As a conventional fuel injection valve, for example, one described in Patent Document 1 is known. In the fuel injection valve (fuel injection device) of Patent Document 1, a valve body and a needle valve are provided on the front end side where fuel is injected.

  The valve body has a bottomed cylindrical shape, a valve seat is provided on the outer peripheral side of the inner wall of the bottom portion, and an inner region of the valve seat is a concave portion recessed on the bottom outer wall side. A plurality of nozzle holes that are arranged in the circumferential direction and that are formed through the bottom wall from the inner wall side to the outer wall side are provided on the center side of the recess. The nozzle hole is a hole having a circular cross-sectional shape, and has a tapered shape whose diameter is increased from the inlet side (the inner wall side of the valve body) toward the outlet side (the outer wall side of the valve body). The axis of the nozzle hole is inclined so as to be away from the cylinder axis of the valve body as it goes from the inner wall side to the outer wall side. Further, the inlet of the nozzle hole is provided so as to be positioned on a virtual plane extending the valve seat.

  The needle valve is a needle-like member and is provided so as to be reciprocally movable in the cylinder axis direction inside the valve body, and the valve seat formed at the tip is seated on or separated from the valve seat. The nozzle hole is opened and closed. The space between the center side tip of the needle valve and the recess of the valve body is a fuel chamber.

  As described above, the inlet of the nozzle hole is provided so as to be located on a virtual plane extending the valve seat, so that the fuel that has passed through the valve seat can directly flow into the nozzle hole. It is like that. That is, the fuel that has passed through the valve seat flows smoothly along the wall surface on the cylinder axis side of the valve body in the nozzle hole while maintaining the kinetic energy, and forms a main flow. ing.

  Further, since the nozzle hole is based on a circular shape and is tapered as described above, the gas phase is large from the vicinity of the axis of the nozzle hole to the vicinity of the wall surface of the nozzle hole located radially outward of the valve body. It is supposed to be formed. Therefore, the liquid film of the fuel (main flow) flowing through the wall surface on the cylinder axis side can be thinned, and high atomization of the fuel injected from the nozzle hole is possible.

Japanese Patent Laying-Open No. 2015-52327

  However, in the fuel injection valve of the above-mentioned Patent Document 1, immediately before the needle valve is seated, the fuel from the valve seat toward the nozzle hole is peeled off at the boundary between the valve seat and the recess by increasing the flow velocity. Head towards the center of the room and slow down and stop. Then, after the needle valve is closed, the fuel stagnating in the fuel chamber flows out as droplets from the nozzle hole. Such a fuel outflow worsens fuel sharpness when the valve is closed. In addition, the spilled fuel adheres to the periphery of the outlet opening of the nozzle hole and forms fuel wetting. When the attached fuel causes incomplete combustion in a high temperature environment, it is deposited as a so-called carbonized deposit, resulting in an increase in particulate matter.

  In view of the above problems, an object of the present invention is to provide a fuel injection valve capable of reliably flowing fuel into an injection hole immediately before a needle valve is seated.

  In order to achieve the above object, the present invention employs the following technical means.

In the first invention, a valve seat (144) formed in a cylindrical shape with a bottom and formed on the outer peripheral side of the inner wall (142) of the bottom portion (141), and an outer wall (143) of the bottom portion on the inner peripheral side of the valve seat A valve body (140) having a recess (145) recessed to the side, and an injection hole (146) formed through the inner wall and the outer wall where a virtual extension plane (Ps) extending from the valve seat to the recess side intersects the surface of the recess )When,
A needle valve (150) having a valve seat (154) that can be seated on or separated from the valve seat, and a convex portion (155) that protrudes toward the inner wall in a region on the inner peripheral side with respect to the valve seat; With
In the fuel injection valve that causes the fuel to flow into the nozzle hole between the valve seat and the valve seat when the valve seat is opened from the valve seat,
The convex part is formed in a cylindrical shape,
The cylindrical peripheral wall surface is formed as a guide portion (155a),
On the virtual plane (P) including the cylinder axis (CL) of the valve body and the center point (HO) of the inlet opening of the nozzle hole, the virtual extension line (L) extending from the guide portion to the nozzle hole side is When the valve seat is seated on the valve seat, the valve seat is set to enter the region of the inlet opening of the injection hole.

In the second invention, the fuel injection valve has a guide portion (147) formed between the end position (Pe) of the valve seat and the inlet opening of the injection hole,
When the valve seat is seated on the valve seat on the virtual plane (P) including the cylinder axis (CL) of the valve body and the center point (HO) of the inlet opening of the nozzle hole, the virtual extension plane and the guide The first angle (θ1) formed by the portion is set smaller than the second angle (θ2) formed by the virtual extension plane and the surface of the convex portion.

  According to the first and second inventions, when the valve seat (154) is seated on the valve seat (144) (immediately before the seat is seated), the guide portions (155a, 147) are formed in the cylinder of the space (160). The fuel can be prevented from flowing into the axial side (center side) and guided (flowed) into the nozzle hole (146).

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment description mentioned later.

It is sectional drawing which shows the whole structure of the fuel injection valve in 1st Embodiment. It is an enlarged view which shows the II section (injection hole) in FIG. It is sectional drawing which shows the flow of the fuel at the time of the valve opening state of 1st Embodiment. It is sectional drawing which shows the flow of the fuel just before seating of a prior art. It is sectional drawing which shows the flow of the fuel just before seating of 1st Embodiment. It is a graph which shows the fuel injection rate before and behind at the time of seating by comparison with 1st Embodiment and a prior art. It is sectional drawing which shows the state of the fuel of the nozzle hole vicinity after the seating of a prior art. It is sectional drawing which shows the state of the fuel of the nozzle hole vicinity after the seating of 1st Embodiment. It is a graph which shows the ejection amount of the fuel after seating by comparison with 1st Embodiment and a prior art. It is sectional drawing which shows the valve body and needle valve of the nozzle hole vicinity in 2nd Embodiment. It is sectional drawing which shows the flow of the fuel at the time of the valve opening state of 2nd Embodiment. It is sectional drawing which shows the flow of the fuel just before seating of 2nd Embodiment. It is a graph which shows the injection rate of the fuel before and after seating by comparison with 2nd Embodiment and a prior art. It is sectional drawing which shows the state of the fuel of the nozzle hole vicinity after the seating of 2nd Embodiment. It is a graph which shows the ejection amount of the fuel after seating by comparison with 2nd Embodiment and a prior art. It is sectional drawing which shows the valve body and needle valve of the nozzle hole vicinity in other Embodiment 1. FIG. It is sectional drawing which shows the valve body and needle valve of the nozzle hole vicinity in other Embodiment 2. FIG. It is sectional drawing which shows the valve body and needle valve of the nozzle hole vicinity in other Embodiment 3. It is sectional drawing which shows the valve body and needle valve of the nozzle hole vicinity in other Embodiment 4.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly indicate that the combination is possible in each embodiment, but also a combination of the embodiments even if they are not clearly specified unless there is a problem with the combination. It is also possible.

(First embodiment)
The fuel injection valve 100 in the first embodiment is shown in FIGS. 1 to 3, 5, 6, 8, and 9. The fuel injection valve 100 is applied to, for example, a direct injection gasoline engine and is mounted on an engine head. The fuel injection valve 100 directly injects fuel pressurized by a high-pressure pump into a cylinder of an engine by opening (opening) a needle valve 150 described later.

  As shown in FIG. 1, the fuel injection valve 100 includes a fixed core 110, a nozzle holder 120, a drive unit 130, a valve body 140, a needle valve 150, and the like. Hereinafter, as the direction of the fuel injection valve 100, the direction in which the fixed core 110 extends is referred to as the axial direction Z (vertical direction in FIG. 1), and one of the axial directions Z is the valve opening direction Z1 (upward in FIG. ) And the other of the axial directions Z is referred to as a valve closing direction Z2 (downward in FIG. 1, the injection hole side).

  The fixed core 110 is a cylindrical member that forms a housing made of a magnetic material, and the inside is a central hole 111 through which fuel flows. An end of the fixed core 110 on the valve opening direction Z1 side is a fuel inlet 111a into which high-pressure fuel flows. In addition, a fuel filter 112 that supplements foreign matters contained in the fuel is provided in the vicinity of the fuel inlet 111 a in the center hole 111. Furthermore, a cylindrical adjusting pipe 113 is fixed by press-fitting or the like at an intermediate position of the center hole 111 closer to the valve closing direction Z2 than the fuel filter 112.

  The nozzle holder 120 is a cylindrical member formed of a magnetic material, and is provided on the end portion side of the stationary core 110 on the valve closing direction Z2 side via a nonmagnetic portion 133 described later. Inside the nozzle holder 120 is a fuel passage 121 through which fuel flows. On the valve opening direction Z1 side of the fuel passage 121, a step portion 122 is provided for restricting the position of an end portion on the valve closing direction Z2 side of a second spring 136 described later.

  The drive unit 130 reciprocates the needle valve 150 along the axial direction Z, and includes a fixed core 110, an electromagnetic coil 131, a magnetic plate 132, a nonmagnetic unit 133, a movable core 134, a first spring 135, and A second spring 136 and the like are provided.

  The electromagnetic coil 131 is provided on the outer periphery of the end of the fixed core 110 on the valve closing direction Z2 side. The magnetic plate 132 is a cylindrical member made of a magnetic material, covers the electromagnetic coil 131, and is provided so as to straddle the fixed core 110 and the nozzle holder 120.

  The nonmagnetic part 133 is a flat cylindrical member formed of a nonmagnetic material, and is interposed between the fixed core 110 and the movable holder 134 and between the fixed core 110 and the nozzle holder 120. . The nonmagnetic part 133 is configured to prevent a magnetic short circuit between the fixed core 110 and the nozzle holder 120.

  The movable core 134 is a member formed in a cylindrical shape from a magnetic material, and is installed on the valve closing direction Z2 side of the fixed core 110 and on the inner peripheral side of the nozzle holder 120 so as to be capable of reciprocating in the axial direction Z. Yes. A central hole portion penetrating in the axial direction Z is formed at the central portion in the radial direction of the movable core 134. An end of the needle valve 150 (described later) on the valve opening direction Z1 side is inserted into the center hole of the movable core 134 so as to be movable with respect to the movable core 134.

  The fixed core 110, the magnetic plate 132, the nozzle holder 120, and the movable core 134 form a magnetic circuit. When the electromagnetic coil 131 is energized from the terminal portion 131b provided in the connector 131a, a magnetic flux is applied to the magnetic circuit. The movable core 134 is sucked toward the fixed core 110 side.

  The first spring 135 is an elastic member using, for example, a coil spring. In the center hole 111 of the fixed core 110, the adjusting pipe 113 and the movable core 134, specifically, a needle valve connected to the movable core 134 is used. It is provided between 150 end portions (stopper portion 151). The first spring 135 presses the needle valve 150 and the movable core 134 in the valve closing direction Z2.

  The second spring 136 is an elastic member using, for example, a coil spring, and is provided between the stepped portion 122 of the nozzle holder 120 and the movable core 134. The second spring 136 presses the movable core 134 toward the valve opening direction Z1, that is, the fixed core 110 side.

  A valve closing force f1 in the valve closing direction Z2 is applied to the movable core 134 via the needle valve 150 by the first spring 135, and a valve opening force f2 in the valve opening direction Z1 is applied by the second spring 136. It has become. The valve closing force f1 by the first spring 135 is set larger than the valve opening force f2 by the second spring 136.

  As shown in FIGS. 1 and 2, the valve body 140 is formed in a bottomed cylindrical shape, and the cylindrical portion is fixed to the inner peripheral surface of the end of the nozzle holder 120 on the valve closing direction Z2 side, for example, by press-fitting or welding. Has been. A valve seat 144, a recess 145, a nozzle hole 146, and the like are formed on the bottom 141 of the valve body 140 having a bottomed cylindrical shape. Note that, in the bottom portion 141, the inner surface 142 of the valve body 140 is an inner wall 142, and the outer surface of the valve body 140 is an outer wall 143. The cylinder axis of the valve body 140 is CL (hereinafter, cylinder axis CL). This cylinder axis CL is the central axis of the fuel injection valve 100.

  The valve seat 144 is formed in a ring shape on the outer peripheral side of the inner wall 142 of the bottom portion 141, and is a surface inclined toward the valve closing direction Z2 from the outer peripheral side toward the inner peripheral side (cylinder axis CL side). The valve seat 144 is a surface on which a valve seat 154 of a needle valve 150 described later is seated or separated.

  The recess 145 is formed on the inner wall 142 as a surface that is recessed toward the valve closing direction Z2 side from the surface of the valve seat 144 on the inner peripheral side of the valve seat 144. In the region of the recess 145, an inclined surface 145 a that inclines toward the valve closing direction Z 2 toward the cylinder axis CL side on the inner peripheral side of the valve seat 144, and further perpendicular to the cylinder axis CL on the center side of the inclined surface 145 a. Flat surface 145b to be formed.

  In the outer wall 143 of the valve body 140, a region corresponding to the recess 145 is formed so as to protrude toward the valve closing direction Z2 and has a spherical shape.

  The injection hole 146 is formed by penetrating from the inner wall 142 side to the outer wall 143 side where the virtual extension plane Ps extending from the valve seat 144 toward the concave portion 145 intersects the inclined surface 145a of the concave portion 145, and the fuel is directed into the engine cylinder The holes are ejected. A plurality of (for example, six) nozzle holes 146 are provided in the circumferential direction around the cylinder axis CL of the valve body 140. Each of the plurality of nozzle holes 146 is formed to be point-symmetric with respect to the cylinder axis CL. The opening on the inner wall 142 side of the nozzle hole 146 is an inlet opening 146a, and the opening on the outer wall 143 side of the nozzle hole 146 is an outlet opening 146b.

  The inlet opening 146a has a circular shape. Further, the outlet opening 146b has a circular shape whose diameter is increased by a predetermined amount with respect to the inlet opening 146a. That is, the nozzle hole 146 is a tapered hole having a diameter expanded from the inlet side toward the outlet side. The outlet opening 146b may be set to the same hole diameter as that of the inlet opening 146a with the diameter expansion amount being zero.

  An axis connecting the circular center of the inlet opening 146a and the circular center of the outlet opening 146b is the injection hole axis HCL. A plane including the cylinder axis CL and the center point HO of the inlet opening 146a is defined as a virtual plane P. On the virtual plane P, the nozzle hole axis HCL is inclined with respect to the cylinder axis CL so as to be separated in the valve closing direction Z2.

  Of the wall surfaces in the injection hole 146 on the virtual plane P, the wall surface on the cylinder axis CL side is a cylinder axis side wall surface 146c. Of the wall surfaces in the injection hole 146 on the virtual plane P, the wall surface on the side facing the cylindrical axis side wall surface 146c is an opposing wall surface 146d.

  Further, the virtual extension plane Ps extended from the valve seat 144 is formed so as to directly intersect the cylinder axis side wall surface 146c of the injection hole 146 by providing the recess 145.

  The needle valve 150 is an elongated valve member extending in the axial direction Z, and an end on the valve opening direction Z1 side is inserted through and connected to the central hole of the movable core 134. The nozzle holder 120 and the valve body 140 is accommodated on the inner peripheral side of 140 so as to be reciprocable (slidable) in the axial direction Z (in the direction of the cylinder axis CL) together with the movable core 134.

  The needle valve 150 reciprocates in the axial direction Z, thereby opening and closing the injection hole 146 of the valve body 140 and intermittently injecting fuel from the injection hole 146. The needle valve 150 is disposed substantially coaxially with the valve body 140. The needle valve 150 includes a stopper portion 151, an internal passage 152, a communication hole 153, a valve seat 154, a convex portion 155, and the like.

  The stopper portion 151 is provided at the end portion on the valve opening direction Z1 side of the needle valve 150 so as to protrude in a bowl shape (in a flange shape) over the entire circumference in the radially outward direction. The stopper portion 151 is configured to restrict the displacement of the needle valve 150 toward the valve closing direction Z <b> 2 with respect to the movable core 134. That is, when the movable core 134 moves to the valve opening direction Z1 side, the needle valve 150 moves together with the movable core 134 to the valve opening direction Z1 side. When the needle valve 150 moves to the valve closing direction Z2 side, the movable core 134 moves to the valve closing direction Z2 side together with the needle valve 150.

  The internal passage 152 is a passage provided in the needle valve 150, and is formed by drilling from the end face on the valve opening direction Z1 side to the middle in the longitudinal direction of the needle valve 150. That is, the internal passage 152 opens on the valve opening direction Z1 side and is closed on the valve closing direction Z2 side.

  The communication hole 153 is formed as a circular hole that penetrates the wall portion in a direction intersecting the internal passage 152 (a direction orthogonal to the present example) at an intermediate position on the closed side of the internal passage 152. A plurality of communication holes 153 are formed in the circumferential direction of the internal passage 152. The internal passage 152 and the communication hole 153 allow the center hole portion 111 of the fixed core 110 and the fuel passage 121 inside the nozzle holder 120 to communicate with each other.

  The valve seat 154 is formed by chamfering along the valve seat 144 of the valve body 140 on the outer peripheral side of the end portion (end surface in the sliding direction) of the needle valve 150 on the valve closing direction Z2 side. The valve seat 154 can be seated on or separated from the valve seat 144.

  The convex portion 155 is a portion that protrudes toward the inner wall 142 of the valve body 140 in a region on the inner peripheral side with respect to the valve seat 154. The convex portion 155 is formed in a flat cylindrical shape. The base portion of the convex portion 155 has a smooth R shape. An outer peripheral portion of the convex portion 155 is a peripheral wall surface 155a and is formed as a guide portion of the present invention. On the virtual plane P, a virtual extension line L extending toward the nozzle hole 146 along the peripheral wall surface 155a is formed at the nozzle hole 146 both when the valve is closed (when seated) and when the valve is opened (when seated). It is set to enter the region of the inlet opening 146a.

  A space 160 is formed between the flat surface 145b of the concave portion 145 and the convex portion 155 regardless of whether the needle valve 150 is closed or opened.

  Next, the operation and effects of the fuel injection valve 100 based on the above configuration will be described with reference to FIGS.

(1) Operation at the time of valve opening First, when energization to the electromagnetic coil 131 is stopped, no magnetic attractive force is generated, and the valve closing force f1 by the first spring 135 is changed to the valve opening force f2 by the second spring 136. Therefore, the needle valve 150 in contact with the first spring 135 moves together with the movable core 134 in the valve closing direction Z2 (injection hole 146 side). As a result, the valve seat 154 of the needle valve 150 is seated on the valve seat 144 (valve closed state).

  When the electromagnetic coil 131 is energized from the valve closed state as described above, a magnetic flux flows in a magnetic circuit formed by the fixed core 110, the magnetic plate 132, the nozzle holder 120, and the movable core 134 by the magnetic field generated in the electromagnetic coil 131. . As a result, a magnetic attractive force is generated between the fixed core 110 and the movable core 134.

  When the sum of the magnetic attractive force generated between the fixed core 110 and the movable core 134 and the valve opening force f2 of the second spring 136 becomes larger than the valve closing force f1 of the first spring 135, the movable core 134 opens. Move in the valve direction Z1. At this time, since the end of the needle valve 150 on the valve opening direction Z1 side is connected to the movable core 134 by the stopper 151, the needle valve 150 moves together with the movable core 134 in the valve opening direction Z1. As a result, the valve seat 154 of the needle valve 150 is separated from the valve seat 144 and the injection hole 146 is opened.

  The fuel that has flowed into the fuel injection valve 100 from the fuel inlet 111a (center hole 111) is the fuel filter 112, the inner peripheral side of the adjusting pipe 113, the first spring 135, the internal passage 152 of the needle valve 150, and the communication hole. 153, the fuel passage 121 of the nozzle holder 120 and the inner peripheral side of the valve body 140 sequentially flow. This fuel flows into the nozzle hole 146 from between the valve seat 144 and the valve seat 154.

  In the nozzle hole 146 of the present embodiment, the cross-sectional shape is a circular shape and is a tapered hole. And the virtual extension plane Ps which extended the surface of the valve seat 144 to the inclined surface 145a side of the recessed part 145 is formed so that it may cross | intersect the cylinder axis side wall surface 146c directly.

  Therefore, as shown in FIG. 3, when the needle valve 150 is separated, the fuel flows smoothly into the nozzle hole 146 from the valve seat 144 side without inhibiting the flow of the needle valve 150. A main phase of the liquid phase is formed along the inner cylinder axis side wall surface 146c. A gas phase flow is formed on the opposite wall surface 146d side.

(2) Operation immediately before valve closing When the energization to the electromagnetic coil 131 is stopped from the valve opening state as described above, the magnetic attractive force between the fixed core 110 and the movable core 134 disappears. Thereby, the valve closing force f1 of the first spring 135 overcomes the valve opening force f2 of the second spring 136, and the needle valve 150 moves in the valve closing direction Z2 together with the movable core 134.

  In the state immediately before the needle valve 150 is seated on the valve seat 144 (immediately before the valve is closed), in the prior art shown in FIG. 4, the gap between the valve seat 144 and the valve seat 154 is reduced, and the fuel flow rate is increased. The fuel is separated at the boundary between the valve seat 144 and the recess 145. The peeled fuel decelerates and flows along the end face of the needle valve 150, and stays on the cylinder axis CL side of the space 160 in a state having a velocity component. The stagnant fuel was flowing out from the nozzle hole 146. Note that “immediately before being seated” can be defined as, for example, when the clearance between the valve seat 144 and the valve seat 154 is equal to or less than a predetermined clearance in the process of being seated.

  Here, in this embodiment, the convex part 155 is provided in the area | region which becomes an inner peripheral side with respect to the valve seat 154 in the valve closing direction Z2 end of the needle valve 150, and the peripheral wall surface 155a of the convex part 155 is provided. It is a guide part. Since the virtual extension line L extending along the peripheral wall surface 155a is set to enter the region of the inlet opening 146a of the injection hole 146, the fuel is guided by the peripheral wall surface 155a as shown in FIG. Then, it is prevented from flowing into the space 160 and is smoothly guided into the nozzle hole 146. The fuel injection amount gradually decreases toward the seating of the needle valve 150. The space 160 is in a state where fuel that does not have a velocity component is stagnant.

  As shown in FIG. 6, immediately before the needle valve 150 is seated, in the present embodiment, the peripheral wall surface 155a can ensure a larger injection amount than in the prior art.

(3) Operation after valve closing When the valve seat 154 of the needle valve 150 is completely seated on the valve seat 144 and the injection hole 146 is closed, basic fuel injection is stopped.

  In the prior art, although the needle valve 150 is seated and decelerated, the fuel stagnating in the space 160 with a velocity component flows out from the nozzle hole 146 as droplets. As shown in FIG. 7, the amount of fuel in the space 160 is reduced by the outflow. This exacerbated the sharpness of the fuel after sitting (FIG. 6).

  On the other hand, in this embodiment, immediately before the needle valve 150 is seated as in (2) above, the fuel is actively ejected from the nozzle hole 146, and the fuel in the space 160 stagnates without having a velocity component. It has become a thing. Therefore, as shown in FIG. 8, after the needle valve 150 is seated, the fuel in the space 160 is maintained by the surface tension and is prevented from flowing out of the nozzle hole 146. That is, as shown in FIG. 6, the fuel sharpness after sitting is improved, and the amount of fuel jetted after sitting can be reduced as shown in FIG.

  In general, from the above (2) and (3), the fuel can surely flow into the injection hole 146 just before being seated in the present embodiment. In addition, since deterioration of fuel sharpness after sitting can be suppressed, fuel wetting caused by fuel adhering around the outlet opening 146b of the nozzle hole 146 can be suppressed. Therefore, deposit accumulation due to incomplete fuel and generation of particulate matter can be suppressed.

(Second Embodiment)
A second embodiment is shown in FIGS. 2nd Embodiment changes the shape of a guide part with respect to the said 1st Embodiment.

  As shown in FIG. 10, in this embodiment, the peripheral wall surface 155 a in the convex portion 155 of the needle valve 150 is abolished, and a tapered surface 147 is provided at the boundary portion with the valve seat 144 in the concave portion 145 of the valve body 140. Thus, a guide portion is formed.

  The convex portion 155 of the needle valve 150 is formed in the inner region of the valve seat 154 so as to have a conical inclined surface 155b that inclines toward the valve closing direction Z2 toward the cylinder axis CL side.

  The tapered surface 147 of the valve body 140 is formed between the end point position Pe of the valve seat 144 and the inlet opening 146a of the injection hole 146. The tapered surface 147 is located closer to the valve closing direction Z2 than the virtual extension plane Ps, and becomes a conical surface that inclines toward the valve closing direction Z2 toward the cylinder axis CL side from the end point position Pe. .

  On the virtual plane P, when the angle formed by the virtual extension plane Ps and the tapered surface 147 is the first angle θ1, and the angle formed by the virtual extension plane Ps and the inclined surface 155b is the second angle θ2, the first angle It is set so that θ1 <second angle θ2. That is, the tapered surface 147 and the inclined surface 155b are arranged so that the tapered surface 147 is closer to the virtual extension plane Ps, and the inclined surface 155b is arranged to be farther from the virtual extension plane Ps. Yes. Therefore, the valve seat 144 and the tapered surface 147 are connected with a relatively large obtuse angle.

  In the present embodiment, when the valve is opened (when the needle valve 150 is separated), as shown in FIG. 11, the fuel inhibits its flow as in the first embodiment (FIG. 3). Instead, it flows smoothly into the nozzle hole 146 from the valve seat 144 side, and forms a liquid-phase mainstream along the cylinder axis side wall surface 146 c in the nozzle hole 146. A gas phase flow is formed on the opposite wall surface 146d side.

  Also, immediately before the needle valve 150 is seated, as shown in FIG. 12, the fuel is continuously guided along the tapered surface 147 without being peeled off at the end point Pe of the valve seat 144. ) And is prevented from flowing into the space 160 and is smoothly guided into the nozzle hole 146. Therefore, the fuel can surely flow into the nozzle hole 146 just before the needle valve 150 is seated. The space 160 is in a state where fuel that does not have a velocity component is stagnant.

  As shown in FIG. 13, the fuel injection amount gradually decreases toward the seating of the needle valve 150. Then, immediately before the needle valve 150 is seated, in the present embodiment, the taper surface 147 can ensure a larger injection amount than the prior art.

  Further, after the valve is closed, as shown in FIG. 14, the fuel in the space 160 having no velocity component is maintained by the surface tension and is prevented from flowing out of the nozzle hole 146. . That is, as shown in FIG. 13, the fuel sharpness after sitting is improved, and the amount of fuel jetted after sitting can be reduced as shown in FIG. Therefore, as in the first embodiment, fuel wetting caused by fuel adhering to the periphery of the outlet opening 146b of the nozzle hole 146 can be suppressed, and deposit accumulation due to incomplete fuel and generation of particulate matter can be achieved. Can be suppressed.

(Other embodiments)
Other Embodiments 1 to 4 are shown in FIGS.

  In the first embodiment, the base portion of the convex portion 155 has a smooth R shape. However, as shown in other embodiment 1 in FIG. 16, it may have a square shape.

  Moreover, as shown in other embodiment 2 of FIG. 17, it is good also as what combined the said 2nd Embodiment (setting of the taper surface 147) with the said 1st Embodiment (setting of the surrounding wall surface 155a).

  Further, in contrast to the second embodiment, as shown in other embodiment 3 of FIG. 18, the end of the needle valve 150 on the valve closing direction Z2 side is formed in a spherical shape, and a part of this spherical surface is formed. The portion that contacts the valve seat 144 when the valve is closed may be the valve seat 154, and the inner peripheral side of the valve seat 154 may be the inclined surface 155b.

  Further, as shown in the other embodiment 4 of FIG. 19, the valve seat 154 is formed in a spherical shape with respect to the second embodiment, the inclined surface 155b is formed on the inner peripheral side of the valve seat 154, and A convex portion 155 that protrudes in a spherical shape may be provided on the inner peripheral side of the inclined surface 155b.

  Moreover, in each said embodiment, although the number of the nozzle holes 146 was six, it is not limited to this.

  Moreover, in each said embodiment, although the front-end | tip of the outer wall 143 of the valve body 140 was made spherical, a plane may be sufficient.

  In each of the above embodiments, the fuel injection valve 100 is applied to a direct-injection gasoline engine. However, the fuel injection valve 100 is not limited to a direct-injection gasoline engine, but a port-injection gasoline engine, a diesel engine, or the like. You may apply to.

DESCRIPTION OF SYMBOLS 100 Fuel injection valve 140 Valve body 141 Bottom 142 Inner wall 143 Outer wall 144 Valve seat 145 Recess 146 Injection hole 147 Tapered surface (guide part)
150 Needle valve 154 Valve seat 155 Convex part 155a Circumferential wall surface (guide part)
CL cylindrical axis HO center point P virtual plane Ps virtual extension plane L virtual extension line Pe end point position θ1 first angle θ2 second angle

Claims (3)

A valve seat (144) formed on the outer peripheral side of the inner wall (142) of the bottom portion (141) and having a bottomed cylindrical shape, and a recess recessed toward the outer wall (143) side of the bottom portion on the inner peripheral side of the valve seat (145), and a valve body having a nozzle hole (146) formed through the outer wall from the inner wall where a virtual extension plane (Ps) extending from the valve seat toward the concave portion intersects the surface of the concave portion ( 140)
A needle valve having a valve seat (154) that can be seated on or separated from the valve seat, and a convex portion (155) that protrudes toward the inner wall in a region on the inner peripheral side with respect to the valve seat ( 150), and
In the fuel injection valve for flowing fuel into the nozzle hole from between the valve seat and the valve seat when the valve seat is opened from the valve seat,
The convex portion is formed in a columnar shape,
The cylindrical peripheral wall surface is formed as a guide portion (155a),
A virtual extension line extending from the guide portion to the nozzle hole side on a virtual plane (P) including the cylinder axis (CL) of the valve body and the center point (HO) of the inlet opening of the nozzle hole (L) is a fuel injection valve set so as to enter the region of the inlet opening of the nozzle hole when the valve seat is seated on the valve seat. A valve seat (144) formed on the outer peripheral side of the inner wall (142) of the bottom portion (141) and having a bottomed cylindrical shape, and a recess recessed toward the outer wall (143) side of the bottom portion on the inner peripheral side of the valve seat (145), and a valve body having a nozzle hole (146) formed through the outer wall from the inner wall where a virtual extension plane (Ps) extending from the valve seat toward the concave portion intersects the surface of the concave portion ( 140)
A needle valve having a valve seat (154) that can be seated on or separated from the valve seat, and a convex portion (155) that protrudes toward the inner wall in a region on the inner peripheral side with respect to the valve seat ( 150), and
In the fuel injection valve for flowing fuel into the nozzle hole from between the valve seat and the valve seat when the valve seat is opened from the valve seat,
A guide portion (147) formed between the end position (Pe) of the valve seat and the inlet opening of the nozzle hole;
When the valve seat is seated on the valve seat on a virtual plane (P) including the cylinder axis (CL) of the valve body and the center point (HO) of the inlet opening of the nozzle hole, A fuel injection valve in which a first angle (θ1) formed by a virtual extension plane and the guide portion is set smaller than a second angle (θ2) formed by the virtual extension plane and the surface of the convex portion.   3. The fuel injection valve according to claim 1, wherein the virtual extension plane is formed so as to directly intersect a wall surface on the cylinder axis side in the injection hole.

Images