JP2016102443A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve capable of reducing occurrence of bulky droplets, in a valve closing process at the time of fuel injection end.SOLUTION: A fuel injection valve includes: a deformable valve body 101; a valve seat surface 203 contacting with the valve body 101 and seating fuel; and a fuel injection hole 201 provided on a downstream side with respect to a seat position 204 on the side of the valve seat surface 203 with which the valve body 101 contacts. A fuel flow passage formed on the downstream side of the seat position 204 has a flow passage cross sectional area increase part 206 in which a cross sectional area increases toward the downstream side. In the flow passage cross sectional area increase part 206, an end part on an upstream side is positioned on the downstream side from a center 216 of an entrance opening surface of the fuel injection hole 201.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fuel injection valve used in an internal combustion engine such as a gasoline engine, wherein a valve body abuts against a valve seat to prevent fuel leakage, and injection is performed when the valve body is separated from a valve seat surface. The present invention relates to a fuel injection valve.

  In JP 2013-160213 A (Patent Document 1), a displaceable valve body, a valve seat surface that contacts the valve body and seats fuel, and a position where the valve seat surface and the valve body contact each other are disclosed. A fuel injection valve having a fuel injection hole provided on the downstream side has an injection hole opening forming surface formed with an inlet opening of the fuel injection hole on the downstream side of the valve seat surface, and the valve seat surface and the fuel injection valve The angle formed by the central axis is formed larger than the angle formed by the injection hole opening forming surface and the fuel injection valve central axis, and the fuel flow path formed between the injection hole opening forming surface and the valve body is formed. There has been disclosed a fuel injection valve in which a valve body can be maintained in an open state in a state where a region in which a cross-sectional area is constant along a fuel flow direction is formed (see summary).

  Japanese Patent Laid-Open No. 2010-38126 (Patent Document 2) discloses that an annular recess that enlarges a cross-sectional area of a flow path is provided directly below a seat portion, and at least a part of an inlet opening of a fuel injection hole is annular. A fuel injection valve that is covered by a recess and has a flow path shape that narrows the gap between the surface of the valve body and the valve seat surface from the deepest portion of the annular recess toward the downstream is disclosed (see summary).

JP 2013-160213 A JP 2010-38126 A

  In recent years, exhaust gas regulations for automobiles have been strengthened. In order to cope with this stricter exhaust gas regulation, it is necessary to promote the vaporization of fuel in the cylinder (combustion chamber). And in order to accelerate | stimulate vaporization, atomization of fuel spray is calculated | required. In particular, in the valve closing process at the end of fuel injection, fuel with a low speed is injected as coarse droplets that are difficult to vaporize. It is necessary to prevent such coarse droplets from being ejected.

  In Patent Document 1, the valve element is opened in a state where a region in which the cross-sectional area of the fuel flow path formed between the injection hole opening forming surface and the valve element is constant along the fuel flow direction is formed. A technique for atomizing fuel by making the state maintainable is disclosed. However, Patent Document 1 does not sufficiently study the fuel flow from the upstream side of the fuel injection hole in the process of closing the valve body at the end of fuel injection (valve closing process). That is, the consideration of the problem that coarse droplets are generated in the valve closing process is not sufficient.

  Further, in Patent Document 2, at least a part of the inlet opening of the fuel injection hole is covered with an annular recess formed in the valve body, and the flow passage cross-sectional area of the inlet opening of the fuel injection hole is enlarged, so that the fuel fine particles A technique for promoting the conversion is disclosed. However, in the technique of Patent Document 2, the presence of the annular depression causes the fuel to be rapidly decelerated during the valve closing process, and the fuel with a slower speed is increased compared to the case where there is no annular depression. For this reason, atomization is hindered in the valve closing process, and there is a possibility that the ejection amount of coarse droplets increases.

  An object of the present invention is to provide a fuel injection valve that can reduce the generation of coarse droplets in the valve closing process at the end of fuel injection.

  In order to achieve the above object, a fuel injection valve according to the present invention includes a displaceable valve body, a valve seat surface that contacts the valve body and seats fuel, and a valve seat surface side that contacts the valve body. In a fuel injection valve having a fuel injection hole provided on the downstream side of the seat position, the fuel passage formed on the downstream side of the seat position increases in the cross-sectional area of the fuel passage. The flow path cross-sectional area increasing portion has an upstream end located downstream from the center of the inlet opening surface of the fuel injection hole.

  According to the present invention, it is possible to reduce fuel adhesion to the combustion chamber wall of a gasoline engine by reducing the generation of coarse fuel droplets in the valve closing process. Thereby, the fuel injection valve which implement | achieves the internal combustion engine which improved exhaust performance can be provided.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is sectional drawing which shows the Example of the fuel injection valve which concerns on this invention. It is sectional drawing to which the vicinity of the valve body front-end | tip and fuel injection hole of the fuel injection valve which concerns on 1st Example of this invention was expanded. FIG. 5 is an enlarged cross-sectional view of the vicinity of a valve body tip and a fuel injection hole according to a comparative example with the first embodiment of the present invention. It is the figure which showed the relationship of the flow-path cross-sectional area in the arbitrary positions on the valve-seat surface of FIG.2 and FIG.3. It is a figure for demonstrating the fuel flow which concerns on 1st Example of this invention, and is the figure which looked at the valve seat surface of the fuel injection valve from the upstream of the fuel flow. It is a figure for demonstrating the fuel flow which concerns on 1st Example of this invention, and is sectional drawing to which the vicinity of the valve body front-end | tip of a fuel injection valve and a fuel injection hole was expanded. It is sectional drawing which expanded the vicinity of the valve body front-end | tip of a fuel injection valve which does not have a flow-path cross-sectional area expansion part, and a fuel injection hole. It is the figure which showed the relationship of the flow-path cross-sectional area in the arbitrary positions on the valve-seat surface of FIG.6 and FIG.7. It is sectional drawing to which the vicinity of the valve body front-end | tip and fuel injection hole of the fuel injection valve which concerns on 1st Example of this invention was expanded. It is sectional drawing to which the vicinity of the valve body front-end | tip and fuel injection hole of the fuel injection valve which concerns on 2nd Example of this invention was expanded. It is sectional drawing to which the vicinity of the valve body front-end | tip and fuel injection hole of the fuel injection valve which concerns on 2nd Example of this invention was expanded.

  Examples according to the present invention will be described below. In the following description, the position in the vertical direction or the vertical direction is defined based on the position in the vertical direction or the vertical direction on the paper surface of FIG. This vertical direction or the position in the vertical direction does not mean the vertical direction or the vertical position in the mounted state of the fuel injection valve.

  A fuel injection valve according to a first embodiment of the present invention will be described below with reference to FIGS.

[Basic operation of fuel injection valve]
FIG. 1 shows a cross-sectional view of one embodiment of a fuel injection valve according to the present invention. In FIG. 1, as an example of the fuel injection valve, an in-cylinder direct injection type electromagnetic fuel injection valve 100 for a gasoline engine is shown, but the effect of the present invention is an electromagnetic fuel for a port injection type gasoline engine. It is also effective in a fuel injection valve driven by an injection valve, a piezo element or a magnetostrictive element.

  In FIG. 1, the fuel is supplied from the fuel supply port 112 and supplied into the fuel injection valve 100. The electromagnetic fuel injection valve 100 shown in FIG. 1 is a normally closed electromagnetic drive type, and when the coil 108 is not energized, the valve body 101 is urged by the spring 110 and pressed against the seat member 102. The fuel is sealed. At this time, in the in-cylinder fuel injection valve, the supplied fuel pressure is in the range of about 1 MPa to 50 MPa.

  FIG. 2 shows an enlarged cross-sectional view of the vicinity of the tip of the fuel injection valve and the fuel injection hole of the fuel injection valve according to the first embodiment.

  When the electromagnetic fuel injection valve 100 is in the closed state, the valve body 101 comes into contact with a valve seat surface 203 formed of a conical surface provided on the seat member 102 whose tip is joined to the nozzle body 104 by welding or the like. As a result, the fuel seal is maintained. At this time, the contact part (valve element side contact part 202) on the valve element 101 side is formed by a spherical portion 202a formed in a substantially spherical shape, and a conical valve seat surface 203 and a spherical valve element side contact are formed. The contact with the contact portion 202 is almost in a line contact state. The spherical valve body-side contact portion 202 has an arcuate shape at least including the valve body-side contact portion 202 with the valve seat surface 203 in a cross section along the axial direction (valve axial direction) of the valve body 101. The convex part formed by the curved surface including the circular arc shape is formed in the tip part of the valve body 101 so as to form a ring (ring shape) along the circumferential direction. In this embodiment, the axis of the valve body coincides with the fuel injection valve central axis 215. The solid line 101a represents the position of the valve body 101 in the valve open state, and the dotted line 101b represents the position of the valve body 101 in the valve closed state.

  When the coil 108 is energized via the connector 111 shown in FIG. 1, magnetic flux density is generated in the core (fixed core) 107, the yoke 109, and the anchor (movable core) 106 constituting the magnetic circuit of the electromagnetic valve. In the valve open state, a gap g (see FIG. 1) is provided between the mutually facing end surfaces of the core 107 and the anchor 106 (the lower end surface of the core 107 and the upper end surface of the anchor 106). By generating a magnetic flux density in the magnetic circuit, a magnetic attractive force is generated between the core 107 and the anchor 106 through the gap g. When the magnetic attraction force becomes larger than the force by the urging force of the spring 110 and the aforementioned fuel pressure, the valve body 101 is attracted to the core 107 side by the anchor 106 while being guided by the guide member 103 and the valve body guide 105 to open the valve. It becomes a state.

  When the valve is opened, a gap St (stroke) is generated between the valve seat surface 203 and the valve element side contact portion 202 of the valve element 101, and fuel injection is started. When fuel injection is started, the energy given as the fuel pressure is converted into kinetic energy and injected into the fuel injection hole 201. The gap St is equal to the gap g.

[Description of characteristics in fuel flow path between valve body and valve seat surface]
Next, the detailed shape of the valve body 101 will be described with reference to FIGS.

  As shown in FIG. 2, the seat member 102 includes a valve seat surface 203 having a point (valve seat surface side contact portion) 204 that contacts the valve body side contact portion 202, and a plurality of fuel injection holes 201. ing. The valve body side contact portion 202 may be referred to as a valve body side seat portion, and the valve seat surface side contact portion 204 may be referred to as a valve seat surface side seat portion.

  The valve body 101 includes a spherical surface portion 202 a having a valve body side contact portion 202 that contacts the valve seat surface 203, a conical surface (tapered surface) 205, and a valve body front end surface 206. The valve body front end surface 206 is on the front end side of the valve body 101 with respect to the conical surface 205 (the side opposite to the anchor 106), and the conical surface 205 is on the front end side of the valve body 101 with respect to the spherical portion 202a. That is, in the fuel flow direction, the spherical portion 202a, the conical surface 205, and the valve element front end surface 206 are arranged in this order from the upstream side toward the downstream side.

  FIG. 3 shows a comparative example with the present embodiment (FIG. 2). In addition, in FIG. 3, the cross-sectional view which expanded the vicinity of a valve body front-end | tip and a fuel-injection hole similarly to FIG. 2 is shown. 3 having the same numbers as those in FIG. 2 have the same functions, configurations and effects as those of the present embodiment.

  In the configuration of FIG. 3, in the valve open state, the distance between the valve body 501 and the valve seat surface 203 is wide from the point A on the valve seat surface 203 toward the point D and further from the point D toward the downstream side. It is comprised so that it may become. For this reason, in the comparative example, the flow path cross-sectional area is configured to gradually increase from the point A on the valve seat surface 203 toward the downstream side of the point D. Point D is the intersection of the inlet opening surface of the fuel injection hole 201 and the fuel injection hole central axis 216.

  FIG. 4 is a diagram illustrating a change in the flow path cross-sectional area of the fuel at each position on the valve seat surface when the valve is opened (for example, at the time of a full stroke). The channel cross-sectional area is defined as follows. For example, let A be the intersection of the valve seat surface 203 and the line segment drawn from the point A ′ of the valve body 101 so as to be perpendicular to the valve seat surface 203. The distance (radius) from the fuel injection valve central axis 215 at the point A is RA, and the fuel injection hole opening is formed in a direction perpendicular to the fuel injection hole opening forming surface (same as the valve seat surface in this embodiment) 203. When the gap between the surface 203 and the valve body 101 is hA, 2 · π · RA · hA is the flow path cross-sectional area at the point A. Hereinafter, it is assumed that the channel cross-sectional area at each position of the valve seat surface 203 is obtained by the same method as described above. The solid line 401 represents the relationship between the flow path cross-sectional area and the valve seat surface position of the embodiment of FIG. 2, and the dotted line 402 represents the relationship between the flow path cross-sectional area and the valve seat surface position of the comparative example of FIG.

  The characteristic of the valve body shape in a present Example is demonstrated using FIG. As indicated by the solid line representing the valve body position 101a in the valve open state, the spherical surface portion 202a of the valve body 101 is connected to the conical surface 205 at a point A ′. When a line segment perpendicularly drawn from the fuel injection valve central axis 215 to the conical surface 205 is a radius of the cone forming the conical surface 205, this radius is formed between the valve seat surface 203 and the valve body 101. The flow path cross-sectional area of the fuel is determined so as to decrease from the upstream side to the downstream side of the valve seat surface 203. The conical surface 205 is connected to the valve body distal end surface 206 at a point C ′. When the valve body 101 is in the closed state (dotted line 101b in FIG. 2), the point C ′ is on the intersection D ′ where the fuel injection hole central axis 216 and the valve body 101 intersect or on the downstream side of the intersection D ′. Position it on the valve body tip side. The valve body front end surface 206 is formed as a concave surface with respect to the conical surface 205. That is, the valve body front end surface 206 is shaped to be recessed inside the valve body 101 in order to increase the cross-sectional area of the fuel flow path. In the present embodiment, the starting position of the concave portion of the valve body 101 is an intersection D ′ where the position 101 b of the valve body 101 in the closed state and the fuel injection hole central axis 216 intersect. That is, the point C ′ on the solid line 101a and the point D ′ on the dotted line 101b represent the same points in the valve open state and the valve closed state, respectively.

  The concave surface 206 at the tip of the valve body described above is provided in a fuel flow path formed on the downstream side of the seat position on the valve seat surface side, and has a flow path cross-sectional area increasing portion whose cross-sectional area increases toward the downstream side. Configure. Since the surface perpendicular to the valve seat surface 203 is a flow path cross section, the flow path cross-sectional area increasing portion 206 has an upstream end located downstream from the center of the inlet opening surface of the fuel injection hole 201 and fuel injection. The hole 201 is positioned upstream of the most downstream portion of the inlet opening edge. The flow passage cross-sectional area increasing portion is constituted by the valve seat surface 203 and the concave portion 206 of the valve body 101.

  The change in the flow path cross-sectional area of the fuel in the valve open state will be described with reference to FIGS. 2, 3, and 4. In FIG. 4, a solid line 401 represents a change in the channel cross-sectional area in the present example (FIG. 2), and a dotted line 402 represents a change in the channel cross-sectional area of the comparative example.

  From the valve seat surface side contact portion 204 to the connection point A between the spherical surface portion 202a and the conical surface 205, the flow path cross-sectional area increases. From point A to point C corresponding to the starting point of the valve body recess 206, the flow path cross-sectional area increases in the comparative example (dotted line 402), and the flow path cross-sectional area decreases in the present embodiment (solid line 401). At point C, the flow path cross-sectional area starts from decreasing to increasing.

  That is, the fuel flow path formed on the downstream side of the seat position on the valve seat surface side has a flow path cross-sectional area gradually decreasing portion that gradually decreases toward the downstream side on the upstream side of the flow path cross-sectional area increasing portion 206. Have. The channel cross-sectional area gradually decreasing portion is constituted by a conical surface 205 formed on the valve body 101 side and a conical surface forming the valve seat surface 203.

  Further, at the point C, the injection amount is set to a clearance hC larger than the flow path cross-sectional area of the valve seat surface side contact portion 204 at the time of valve opening (at the time of full stroke). It is possible to adjust by the gap St. The fuel injection valve of the present embodiment is characterized by such a change in the flow path cross-sectional area. In the present embodiment, the flow path cross-sectional area is changed from decrease to increase / decrease at the point C, but the position where the flow passage changes from decrease to increase / decrease may be downstream of the point C, and the inlet opening of the fuel injection hole 201 It is preferable that it is upstream from the most downstream position E of the edge.

[Stroke effect]
The cross-sectional area of the flow path formed between the valve seat surface 203 and the valve body 101 varies depending on the stroke (St) of the valve body 101. For example, depending on the value of the stroke, the magnitude relationship may be reversed between the flow path cross-sectional area at the valve seat surface side contact portion 204 and the flow path cross-sectional area at the point C.

  For example, in a fuel injection valve in which a valve element can be maintained open at an arbitrary stroke position using a piezoelectric element or the like, the flow path cross-sectional area tends to be as shown by a solid line 401 in FIG. The shape of the conical surface 205 and the shape of the valve body tip surface 206 (concave portion) can be designed by arbitrarily selecting the stroke position up to the full stroke (maximum stroke). In addition, in the case of a fuel injection valve having a structure in which the valve body cannot be maintained open at an arbitrary stroke position, the flow path is cut off in a state where the displacement of the valve body is regulated by a stopper that determines the stroke amount (full stroke state). What is necessary is just to design the shape of the conical surface 205 and the shape of the valve body front end surface 206 so that the area tends to be a solid line 401 in FIG.

  In the embodiment according to the present invention, the increase / decrease in the cross-sectional area of the flow path formed between the valve seat surface 203 and the valve body 101 is increased from the point A in FIG. It is required to design so as to be in a state as indicated by the point D.

[Description of flow and effects]
The operation and effect obtained by configuring the valve body 101 and the fuel injection hole 201 as described above will be described with reference to FIGS.

  FIG. 5 shows a view of the valve seat surface of the fuel injection valve as seen from the upstream side of the fuel flow. In FIG. 5, 210a, 210b, 210c and 210d indicate fuel flow. In FIG. 5, two fuel injection holes 201 a and 201 b are drawn as the fuel injection holes 210.

  As shown in the fuel flow in FIG. 5 (for example, 210a and 210b), the fuel flowing from the upstream flows into the fuel injection holes 201a and 201b from the upstream side of the fuel injection holes 201a and 201b. A part of the fuel (for example, 210c and 210d) once gathers at the tip side of the valve body 101, and then changes the flow direction to flow into the fuel injection holes 201a and 201b from the downstream side of the fuel injection holes 201a and 201b. . This flow is similar in the valve closing process in which the gap between the valve seat surface 203 and the valve body 101 gradually decreases, and the speed of the fuel 210a flowing into the fuel injection holes 201a and 201b from the upstream side of the fuel injection holes 201a and 201b. By preventing the drop, the air shear splitting of the fuel due to the speed can be promoted, and coarse droplets can be reduced. Therefore, in this embodiment, as indicated by the solid line 401 in FIG. 4, the shape of the conical surface 205 is determined from point A to point C so as to reduce the flow path cross-sectional area.

  Next, the effect of the concave shape (increase in cross-sectional area) of the valve body distal end surface 206 will be described with reference to FIGS.

  FIG. 6 shows an enlarged cross-sectional view of the vicinity of the tip of the fuel injection valve and the fuel injection hole. FIG. 6 is a diagram for explaining the fuel flow according to the present embodiment.

  As shown in FIG. 6, the fuel 310 a flows from the upstream side of the fuel injection hole 201 toward the fuel injection hole 201. At this time, the fuel flow flowing into the fuel injection hole 201 forms a separation region 212a. On the other hand, the fuel 310 b flows from the downstream side of the fuel injection hole 201 toward the fuel injection hole 201. At this time, the fuel flow flowing into the fuel injection hole 201 forms a separation region 212b.

  FIG. 7 shows an enlarged cross-sectional view of the vicinity of the tip of the fuel injection valve and the fuel injection hole of the fuel injection valve that does not have the flow passage cross-sectional area enlarged portion.

  As shown in FIG. 7, the fuel 410 a flows from the upstream side of the fuel injection hole 201 toward the fuel injection hole 201. At this time, the fuel flow flowing into the fuel injection hole 201 forms a separation region 212a. On the other hand, the fuel 410 b flows from the downstream side of the fuel injection hole 201 toward the fuel injection hole 201. At this time, the fuel flow flowing into the fuel injection hole 201 forms a separation region 312.

  FIG. 8 shows the relationship of the flow path cross-sectional areas at arbitrary positions on the valve seat surface of FIGS. 6 and 7. In FIG. 8, the solid line 402 indicates the flow path cross-sectional area in the case of FIG. 6, and the dotted line 403 indicates the flow path cross-sectional area in the case of FIG. 7.

  If there is no recess in the valve element front end face 206 as shown in FIG. 7, the change in the channel cross-sectional area becomes as shown by the dotted line 403 in FIG. 8, and the downstream side of the fuel injection hole 201 having a small channel cross-sectional area. As a result, the fuel speed increases. Therefore, as shown in FIG. 7, the fuel flow 410b has a high velocity, and when it flows into the injection hole 201, a large separation region 312 is formed with respect to the separation region 212b in FIG.

  On the other hand, by providing the concave shape 206 as shown in FIG. 6, the cross-sectional area of the flow path can be increased on the downstream side of the fuel injection hole 201, and the flow velocity of the fuel can be decreased. Thereby, generation | occurrence | production of peeling can be suppressed and the peeling area | region 212b can be made small with respect to the peeling area | region 312. FIG. As a result, it is possible to reduce the generation of coarse droplets in the valve closing process.

  In this embodiment, the flow path cross-sectional area of the fuel formed between the conical surface 205 and the valve seat surface 203 is gradually decreased from the upstream side toward the downstream side, and the flow rate coefficient at the time of valve opening increases. Atomization at the time of valve opening can be promoted. As a result, in this embodiment, it is possible to promote both atomization at the time of valve opening and reduction of generation of coarse droplets during the valve closing process.

  The effective range of the starting point of the concave portion of the valve element front end surface (starting point of increase in flow path cross-sectional area) will be described with reference to FIG. FIG. 9 is an enlarged cross-sectional view of the vicinity of the valve body tip and the fuel injection hole of the fuel injection valve according to the present embodiment. FIG. 9 shows a valve closing state.

  The starting point of the recess 206 is defined by the positional relationship among the conical surface 205 in the valve-closed state, the valve element front end surface 206 and the fuel injection hole 201. That is, as described with reference to FIG. 5, the starting point of the recess 206 needs to be determined in consideration of the fact that most of the fuel flows from the upstream side of the fuel injection hole 201 when the valve is opened including the valve closing process. Further, the starting point of the recess 206 needs to take into account the reduction in separation of the fuel flowing in from the downstream side of the injection hole described in FIGS. 6 and 7 in the fuel injection hole 201. Therefore, the starting point of the recess 206 on the front end surface of the valve body is a point (part) located on the most downstream side of the inlet opening edge of the fuel injection hole 201 downstream from the point D ′ with reference to the fuel injection hole central axis 216. It is desirable to be in the range 217 upstream of the point E ′ corresponding to E. A point E ′ is an intersection where a line segment perpendicular to the valve seat surface 203 from the point E intersects with the valve body 101.

  The valve element front end surface 206 formed thereby has a shape as indicated by a dotted line 206a when the start point of the recess is at the most upstream side, and is indicated by a solid line 206b when the start point of the recess is at the most downstream side. Shape. Further, the starting point of the recess 206 on the front end surface of the valve body is defined with reference to the fuel injection hole with the center of the injection hole being the most downstream among the plurality of fuel injection holes 201.

[Others]
In the present embodiment, the case where the fuel injection hole 201 is cylindrical has been described. However, even when the fuel injection hole 201 is linear or curved toward the outlet and is enlarged or reduced, the same effect can be obtained. The effects of the invention are not impaired. Further, in this embodiment, the valve seat surface 203 and a part of the valve body 101 are configured in a conical shape. However, even if the valve seat surface 203 has a curved surface, the position of the fuel flow passage cross-sectional area and the valve seat surface 203 If the relationship is that of the present embodiment, the same effect can be obtained.

  A fuel injection valve according to a second embodiment of the present invention will be described below with reference to FIGS. 10 and 11 are cross-sectional views showing the configuration of the valve body of the fuel injection valve in this embodiment, and are enlarged cross-sectional views of the vicinity of the valve body tip and the fuel injection hole. Those assigned the same numbers as in FIG. 2 have the same or equivalent functions as in the first embodiment, and will not be described.

  The difference from the first embodiment is the shape of the valve body distal end surface 206. In the first embodiment, the valve body tip surface 206 has a concave shape, but the cross-sectional area of the flow path is the same even when the curved surface shape 206c and the shape of the valve body tip portion 206d are cut as shown in FIGS. It is effective if the conditions described in one embodiment are satisfied. That is, in this embodiment, the flow passage cross-sectional area increasing portion whose cross-sectional area increases toward the downstream side is configured by the curved surface shape 206c or the shape 206d obtained by cutting the valve body tip portion with a flat surface. Other configurations are the same as those in the first embodiment.

[Others]
In the present embodiment, the case where the fuel injection hole 201 is cylindrical has been described. However, even when the fuel injection hole 201 is linear or curved toward the outlet and is enlarged or reduced, the same effect can be obtained. The effects of the invention are not impaired. Further, in this embodiment, the valve seat surface 203 and a part of the valve body 101 are configured in a conical shape. However, even if the valve seat surface 203 has a curved surface, the position of the fuel flow passage cross-sectional area and the valve seat surface 203 If the relationship is that of the present embodiment, the same effect can be obtained.

  According to each embodiment of the present invention, atomized fuel spray, which is easily vaporized when the valve is opened, can be directly injected into the cylinder, and the generation of coarse droplets is also performed during the valve closing process at the end of injection. Can be reduced. That is, according to each embodiment of the present invention, the atomization of the spray injected from the fuel injection valve is promoted when the valve is opened, and the generation of coarse fuel droplets is reduced during the valve closing process. Thus, it is possible to provide a fuel injection valve that can reduce the adhesion of fuel to the wall surface of the combustion chamber of the gasoline engine and realize an internal combustion engine with improved exhaust performance.

  In addition, this invention is not limited to each above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 100 ... Electromagnetic fuel injection valve 101,501,601,701,801 ... Valve body 101a, 501a ... Valve body position 101b, 501b of a valve opening state ... Valve body position 102 of a valve closing state ... Seat member 103 ... Guide member 104 ... Nozzle body 105 ... Valve body guide 106 ... Anchor 107 ... Core 108 ... Coil 109 ... Yoke 110 ... Spring 111 ... Connector 112 ... Fuel supply port 201, 201a, 201b ... Fuel injection hole 202 ... Valve body side contact part 202a ... Spherical surface Site 203, 303 ... Valve seat surface 204 ... Valve seat surface side contact portion 205, 505 ... Conical surface 206, 206a, 206b, 206c, 206d of valve body ... Valve body tip surface 210a, 210b, 210c, 210d, 310a, 310b, 410a, 410b ... Fuel flow 212, 312 ... Fuel separation region 215 ... Fuel injection valve center 216 ... fuel injection hole central axis 217 ... scope of increasing the starting point of the channel cross-sectional area 401, 402, 403 ... position and the flow path cross-sectional area relationship

Claims (5)

A displaceable valve body; a valve seat surface that contacts the valve body and seats fuel; and a fuel injection hole provided downstream of a seat position on the valve seat surface side that contacts the valve body. In the fuel injection valve,
The fuel flow path formed on the downstream side of the seat position has a flow path cross-sectional area increasing portion whose cross-sectional area increases toward the downstream side,
In the fuel injection valve, the upstream end of the flow path cross-sectional area increasing portion is located downstream from the center of the inlet opening surface of the fuel injection hole. The fuel injection valve according to claim 1, wherein
The flow passage cross-sectional area increasing portion is located on the upstream side of the portion located on the most downstream side of the inlet opening edge of the fuel injection hole. The fuel injection valve according to claim 2,
The fuel injection valve according to claim 1, wherein the fuel flow path has a flow path cross-sectional area gradually decreasing portion that gradually decreases in cross section toward the downstream side, upstream of the flow path cross-sectional area increasing portion. The fuel injection valve according to claim 3,
The flow passage cross-sectional area gradually decreasing portion is constituted by a conical surface formed on the valve body side and a conical surface forming the valve seat surface. The fuel injection valve according to claim 4, wherein
The flow passage cross-sectional area increasing portion is constituted by a concave portion formed in a concave shape with respect to a conical surface formed on the valve body side.

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