Patent Application
20190101087
The present invention relates to a fuel injection valve which generates swirl fuel on the upstream sides of fuel injection holes and injects the swirl fuel from the fuel injection holes.
As a background technology of the present technical field, a fuel injection valve has been known which is described in a Japanese Patent Application Publication No.
2012-215135 (patent document 1). This fuel injection valve includes: a valve body swingably provided; a valve seat member in which a valve seat on which the valve body is seated at the time of valve closing and which has an opening part on the downstream side of the valve seat; swirl imparting chambers for imparting swirling force to fuel by making swirl to the fuel inside them; injection holes which are formed on the bottoms of the swirl imparting chambers; and communication passages which communicate the swirl imparting chambers with the opening part of the valve seat member. When the diameter of the swirl imparting chamber is D, the width of the communication passage is W, they are formed to satisfy the equation 0.15 W/D<0.5 (see abstract). In addition, in this fuel injection valve, three sets of fuel passages each formed of a swirl imparting chamber, a communication passage and a fuel injection hole are provided in a nozzle plate, and each of three sets of fuel communication passages is connected to each other in a central chamber formed in the vicinity of the center of the nozzle plate (see paragraph [0015]).
In addition, in a Japanese Patent Application Publication No. 2014-173479, a fuel injection valve has been described which includes swirling chambers each having an inner peripheral wall whose curvature is gradually larger from upstream to downstream, paths for swirling each of which, having a fuel flow-in region formed along a valve axis direction, guides fuel to the associated one of the swirling chambers, and fuel injection orifices open into the associated swirling chambers, respectively, and a curved portion in the fuel injection valve is formed on the bottom of an inlet portion of each of the paths for swirling so as to change the fuel flow (see abstract). In this fuel injection valve, an orifice plate (corresponding to the nozzle plate of the patent document 1) has four paths for swirling which extend radially outwardly from the center of the orifice plate while being circumferentially equidistantly spaced from one another (to be 90 degrees apart) (see paragraphs [0023] and [0024]).
In the fuel injection valve of the patent document 1, since the three sets of the communication passages are connected in the vicinity of the center of the nozzle plate, the passage length of each of the communication passages becomes long. Consequently, the dead volume of a fuel passage formed on the downstream side of the valve seat becomes large. In contrast to this, in the fuel injection valve of the patent document 2, four sets of the paths for swirling are formed independent of each other, and thereby the length of a fuel passage formed on the downstream side of the valve seat can be shortened.
In the fuel injection valve of the patent document 2, as shown in, for example,
With this configuration, when the position between the valve seat member (in the patent document 2, it is referred to as a nozzle plate) formed with the fuel inlet and the orifice plate (nozzle plate) formed with the paths for swirling deviate is shifted, in a path for swirling, the opening edge of the fuel inlet intersects the arc-shaped portion, and the passage cross-sectional area of this path for swirling which faces the fuel inlet is changed at the arc-shaped portion. If the passage cross-sectional area facing the fuel inlet is changed at the arc-shaped portion, as compared with a case where it is changed at the linear section of the path for swirling, the rate of change in the passage cross-sectional area facing the fuel inlet to the amount of the position deviation between the valve seat and the nozzle plate becomes large, and variation in the flow amount of fuel flowing into a plurality of the paths for swirling (communication passages) becomes large.
An object of the present invention is to provide a fuel injection valve which is capable of suppressing variation in the fuel amount of fuel flowing into a plurality sets of communication passages (hereinafter, referred to as horizontal passages) even in a case where position variation occurs between a valve seat member and a nozzle plate.
To achieve above object, a fuel injection valve of the present invention includes:
fuel injection holes configured to inject fuel to an outside;
a valve body configured to open and close a fuel passage in cooperation with a valve seat, on upstream sides of the fuel injection holes;
a valve seat member formed with the valve seat; and
a nozzle plate in which a plurality of swirl passages are formed and which is connected to a distal end surface of the valve seat member, wherein the swirl passages each include:
a swirl chamber for allowing fuel to be swirled to flow to a corresponding one of the fuel injection holes; and
a horizontal passage which is connected to an upstream side of the swirl chamber and which supplies fuel to the swirl chamber, wherein the valve seat member is opened to the distal end surface to which the nozzle plate is connected and includes a fuel inlet which is connected to an upstream-side end portion of the horizontal passage and introduces fuel into the plurality of the swirl passages, wherein the horizontal passage includes two side-section side surfaces extending along a fuel flow direction and having a linear section, and includes, on an upstream side thereof, an end-section side surface which is formed between the two side-section side surfaces and which has a curved section connected to the linear section, wherein when the fuel inlet and the horizontal passage are projected onto a plane perpendicular to a valve axial center, a projected line of the linear section of the side-section side surfaces of the horizontal passage extends to a place intersecting a projected line of an opening edge of the fuel inlet, and the upstream-side end portion of the horizontal passage extends toward an inside of the opening edge, and wherein, in the plurality of the swirl passages, all of the swirl passages each have a distance dimension equal to 0 or larger between a connection place of the linear section and the curved section and the intersection place of the projected line of the opening edge of the fuel inlet and the projected line of the linear section, and at least one of the swirl passages has a distance dimension larger than 0 between the connection place of the linear section and the curved section and the intersection place of the projected line of the opening edge of the fuel inlet and the projected line of the linear section.
According to the present invention, even if positional deviation occurs between the valve seat member and the nozzle plate, a change in the passage sectional area of the horizontal passages facing the fuel inlet can be small, and thereby a variation in the flow amount of the fuel flowing into a plurality of the horizontal passages can be suppressed.
An embodiment of the present invention will be explained with reference to the drawings.
The whole configuration of a fuel injection valve 1 will be explained with reference to
The fuel injection valve 1 is provided with the cylindrical body 5 made of metal which extends from the upper end part to the lower end part of the fuel injection valve 1. The cylindrical body 5 is formed with, in the inside thereof, a fuel passage 3 substantially along the central axis 1a. In
The cylindrical body 5 is provided with, at the base end part thereof, a fuel supply port 2. This fuel supply port 2 is provided with a fuel filter 13. The fuel filter 13 is a member to remove foreign substances mixed in fuel.
An O-ring 11 is disposed at the base end part of the cylindrical body 5. The O-ring 11 functions as a seal material when the fuel injection valve 1 is connected to the fuel pipe.
The cylindrical body 5 is formed with, at the distal end part thereof, a valve part 7 formed of the valve body 17 and a valve seat member 15. The valve seat member 15 is formed with a valve body accommodation hole 15a having a step to accommodate the valve body 17. A conical surface is formed in the middle of the valve body accommodation hole 15a, and the valve seat (seal part) 15b is formed on this conical surface. A guide surface 15c to guide the movement of the valve body 17 in a direction along the central axis 1a is formed at a part on the upstream side (base end side) more than the valve seat 15b of the valve accommodation hole 15a. The valve seat 15b performs the opening/closing of a fuel passage in cooperation with the valve body 17. The valve body 17 comes in contact with the valve seat 15b, and the fuel passage is closed. In addition, the valve body 17 is separated from the valve seat 15b, and the fuel passage is opened.
The valve seat member 15 is inserted into the inside on the distal end side of the cylindrical body 5, and is fixed to the cylindrical body 5 by laser welding. A laser welding 19 is formed over the entire circumference from the outer circumferential side of the cylindrical body 5. The valve body accommodation hole 15a penetrates through the valve seat member 15 in the direction along the central axis 1a. A nozzle plate 21n formed of a thin plate-shaped member is attached to the lower end surface (distal end surface, downstream-side end surface) of the valve seat member 15. The nozzle plate 21n closes the opening of the valve seat member 15 which is formed by the valve accommodation hole 15a.
In the present embodiment, the valve seat member 15 and the nozzle plate 21n form a fuel injection part 21 configured to inject swirl fuel. The nozzle plate 21n is fixed to the valve seat member 15 by laser welding. A laser welding portion 23 is formed around the circumference of an injection hole forming region at which fuel injection holes 220-1, 220-2, 220-3 and 220-4 (see
In the present embodiment, a ball valve having a spherical shape is used as the valve body 17. In the valve body 17, a part facing a guide surface 15c is provided with a plurality of notched surfaces 17a formed at intervals in a circumferential direction, and a gap is formed between the notched surfaces 17a and the inner circumferential surface of the valve seat member 15. By this gap, a fuel passage is formed. In addition, the valve body 17 can be formed by a valve body other than the ball valve. For example, a needle valve may be used.
In the present embodiment, the valve part 7 including the valve seat member 15 and the valve body 17 and the nozzle plate 21n form a nozzle part configured to inject fuel. The nozzle plate 21n in which the after-mentioned fuel injection holes 220 and passages 210 for swirl (horizontal passages 211 and swirl chambers 212) are formed is joined to the distal end surface of a nozzle part main body (valve seat member 15) at which the valve part 7 is formed.
A drive part 9 configured to drive the valve body 17 is disposed in the middle part of the cylindrical body 5. The drive part 9 is formed by an electromagnetic actuator. Specifically, the drive part 9 is formed of a fixed iron core 25, the movable element (movable member) 27, an electromagnetic coil 29 and a yoke 33.
The fixed iron core 25 is made of a magnetic metal material, and is press-fitted into and fixed to the inside of the middle part in the longitudinal direction of the cylindrical body 5. The fixed iron core 25 is formed in a cylindrical shape, and has a through hole 25a penetrating through the center part thereof in the direction along the central axis 1a. The fixed iron core 25 may be fixed to the cylindrical body 5 by welding, or may be fixed to the cylindrical body 5 by using welding with press-fitting.
In the inside of the cylindrical body 5, the movable element 27 is disposed on the distal end side with respect to the fixed iron core 25. A movable iron core 27a is provided on the base end side of the movable element 27. The movable iron core 27a faces the fixed iron core 25 via a minute gap 6. A small diameter part 27b is formed on the distal end side of the movable element 27, and the valve body 17 is fixed to the distal end of this small diameter part 27b by welding. In the present embodiment, although the movable iron core 27a and the small diameter part 27b are formed integrally with each other (one member made of the same material), they may be formed by joining two members. The movable element 27 is provided with the valve body 17, and displaces the valve body 17 in a valve opening/closing direction. The valve body 17 comes in contact with the valve seat member 15 and the outer circumferential surface of the movable iron core 27a comes in contact with the inner circumferential surface of the cylindrical body 5, and the movement of the movable element 27 in the direction along the central axis 1a (valve opening/closing direction) is guided by two points in a valve axial center direction.
A concave part 27c is formed on the end surface of the movable iron core 27a which faces the fixed iron core 25. A spring seat 27e of a spring (coil spring) 39 is formed on the bottom surface of the concave part 27c. A through hole 27f which penetrates to the end portion on the distal end side of the small diameter part (connection part) 27b is formed on the inner circumferential side of the spring seat 27e along the central axis 1a. In addition, an opening part 27d is formed on the side surface of the small diameter part 27b. The through hole 27f is opened to the bottom surface of the concave part 27c and the opening part 27d is opened to the outer circumferential surface of the small diameter part 27b, and a fuel flow passage 3 is formed which communicates a fuel flow passage 3 formed in the fixed iron core 25 with the valve part 7.
The electromagnetic coil 29 is fitted onto the outer circumferential side of the cylindrical body 5 at a position at which the fixed iron core 25 faces the movable iron core 27a via the minute gap 6. The electromagnetic coil 29 is wound around a cylindrical bobbin 31 made of a resin material, and is fitted onto the outer circumferential side of the cylindrical body 5. The electromagnetic coil 29 is electrically connected to a connector pin 43 disposed in a connector 41 via a wiring member 45. A drive circuit which is not shown in the drawings is connected to the connector 41, and drive current is fed to the electromagnetic coil 29 via the connector pin 43 and the wiring member 45.
The yoke 33 is made of a metal material having magnetism. The yoke 33 is disposed so as to cover the electromagnetic coil 29 on the outer circumferential side of the electromagnetic coil 29, and also serves as a housing for the fuel injection valve 1. In addition, the lower end part of the yoke 33 faces the outer circumferential surface of the movable iron core 27a via the cylindrical body 5, and the movable iron core 27a, the fixed iron core 25 and the yoke 33 form a closed magnetic path through which a magnetic flux generated by energizing the electromagnetic coil 29 flows.
The coil spring 39 is set over the through hole 25a of the fixed iron core 25 and the concave part 27c of the movable iron core 27a in a compressed state. The coil spring 39 functions as a biasing member for biasing the movable element 27 in the direction in which the valve body 17 comes in contact with the valve seat 15b (valve closing direction). An adjuster (adjusting element) 35 is disposed on the inner side of the through hole 25a of the fixed iron core 25, and the end portion on the base end side of the coil spring 39 comes in contact with the end surface on the distal end side of the adjuster 35. By adjusting the position of the adjuster 35 in the through hole 25a in the direction along the central axis 1a, the biasing force of the movable element 27 (that is, the valve body 17) by the coil spring 39 is adjusted.
The adjuster 35 has a fuel flow passage 3 penetrating through the center part of the adjuster 35 in the direction along the central axis 1a. After flowing through the fuel flow passage 3 of the adjuster 35, fuel flows through the fuel flow passage 3 at the distal end side part of the through hole 25a of the fixed iron core 25, and then flows through the fuel flow passage 3 formed inside the movable element 27.
An O-ring 46 is fitted onto the distal end part of the cylindrical body 5. The O-ring 46 functions as a seal for securing liquid-tightness and airtightness between the inner circumferential surface of an insertion port 109a (see
A resin cover 47 is molded in a range from the middle part to a part close to the end portion on the base end side of the fuel injection valve 1. The end portion on the distal end side of the resin cover 47 covers a part on the base end side of the yoke 33. In addition, the resin cover 47 covers the wiring member 45, and the connector 41 is integrally formed by the resin cover 47.
Next, operation of the fuel injection valve 1 will be explained.
When the electromagnetic coil 29 is in a non-energization state (that is, the drive current is not fed to the electromagnetic coil 29), the movable element 27 is biased in the valve closing direction by the coil spring 39, and the valve body 17 is in a state of being in contact with the valve seat 15b (seating state). In this case, the gap 6 exists between the end surface on the distal end side of the fixed iron core 25 and the end surface on the base end side of the movable iron core 27a. In the present embodiment, the distance of this gap 6 is equal to that of the stroke of the movable element 27 (that is, the valve body 17).
When the electromagnetic coil 29 is energized, and the drive current is fed to the electromagnetic coil 29, a magnetic flux is generated in the closed magnetic path formed by the movable iron core 27a, the fixed iron core 25 and the yoke 33. By this magnetic flux, magnetic attraction force is generated between the fixed iron core 25 and the movable iron core 27a which are opposed to each other with the gap 6 interposed therebetween. When this magnetic attraction force overcomes the resultant force of the biasing force by the coil spring 39 and fuel pressure acting on the movable element 27 in the valve closing direction, the movable element 27 starts moving in the valve opening direction. When the valve body 17 is separated from the valve seat 15b, a gap (fuel passage) is formed between the valve body 17 and the valve seat 15b, and fuel injection stars. In the present embodiment, when the movable element 27 moves by a distance equal to the gap 6 in the valve opening direction, and the movable iron core 27a comes in contact with the fixed iron core 25, the movement of the movable iron core 27a in the valve opening direction is stopped, and the valve is opened, and then it becomes a stationary state.
When the energization to the electromagnetic coil 29 is stopped, the magnetic attraction force is lowered, and then disappears. At this stage in which the magnetic attraction force is lowered, when the magnetic attraction force becomes smaller than the biasing force of the coil spring 39, the movable element 27 starts moving in the valve closing direction. When the valve body 17 comes in contact with the valve seat 15b, the valve part 7 is closed and the valve body 17 becomes a stationary state.
As mentioned above, the valve body 17 and the valve seat 15b cooperatively perform the opening/closing of the fuel passage on the upstream side of the fuel injection holes.
Next, with reference to
In addition,
As shown in
The distal end surface (lower end surface) 15t of the valve seat member 15 is formed by a flat surface (plane surface) perpendicular to the central axis 1a. The distal end surface 15t of the valve seat member 15 is joined with the nozzle plate 21n, and the distal end surface 15t comes in contact with the upper end surface 21nu of the nozzle plate 21n.
As shown in
The horizontal passages 211-1, 211-2, 211-3 and 211-4 and the swirl chambers 212-1, 212-2, 212-3 and 212-4 form the swirl passages 210-1, 210-2, 210-3 and 210-4 for applying swirling force to fuel on the upstream sides of the fuel injection holes 220.
The swirl chambers 212-1, 212-2, 212-3 and 212-4 are configured to allow fuel to flow into the fuel injection holes 220-1, 220-2, 220-3 and 220-4 respectively while swirling the fuel.
The horizontal passages 211-1, 211-2, 211-3 and 211-4 are fuel passages extending in a direction along the plate surface of the nozzle plate 21n, are connected on the upstream sides of the swirl chambers 212-1, 212-2, 212-3 and 212-4 respectively, and are configured to supply fuel to the swirl chambers 212-1, 212-2, 212-3 and 212-4 respectively.
In addition, the components of the swirl passages 210-1, 210-2, 210-3 and 210-4 in the present embodiment are different from those of the swirl passages in the patent document 2.
Four sets of the swirl passage 210-1 and the fuel injection hole 220-1, the swirl passage 210-2 and the fuel injection hole 220-2, the swirl passage 210-3 and the fuel injection hole 220-3 and the swirl passage 210-4 and the fuel injection hole 220-4 are each configured similarly, and without distinguishing them, they are explained as swirl passages 210, horizontal passages 211, swirl chambers 212 and fuel injection holes 220. In case where the configuration is changed in each of the sets, it will be explained appropriately.
As shown in
The swirl passages 210 are provided such that the end portions on the upstream sides of the horizontal passages 211 face the opening surface of the fuel inlet 300 to receive fuel supply from the fuel inlet 300. In the present embodiment, as shown in
In
In addition, in the present embodiment, as shown in
In the present embodiment, as shown in
In the embodiment, in total, four sets of the fuel passages formed of the swirl passages 210 and the fuel injection holes 220 are formed in the nozzle plate 21n. Each of the four sets of the fuel passages is formed radially outward from the center 21no side of the nozzle plate 21n toward outside. That is, the horizontal passages 211 are provided radially outward from the center 21no side of the nozzle plate 21 toward outside and extend in the radial direction of the nozzle plate 21n. In addition, the fuel passages are formed circumferentially so as to be spaced from one another at an angle interval of 90°. Moreover, in the four sets of the swirl passages 210, each of the end portions on the upstream sides of the horizontal passages 211 is provided at an equal distance from the center 21no of the nozzle plate 21n.
The number of the sets of the swirl passages 210 and the fuel injection holes 220 is not limited to four, and it can be two or three, or five or more.
Here, with reference to
A horizontal passage 211 is connected to a swirl chamber 212 so as to be offset with respect to the center of the swirl chamber 212. The inner circumferential wall (side wall) of the swirl chamber 212 is formed such that the curvature thereof becomes gradually large from the upstream side toward the downstream side in a flow direction of a swirling fuel. The inner circumferential wall (side wall) of the swirl chamber 212 can be formed with a fixed curvature from the upstream side toward the downstream side in the flow direction of the swirling fuel.
In the present embodiment, side wall sections (side-section side surfaces) 211a and 211b of the horizontal passage 211 is formed to extend linearly from the upstream side toward the downstream side. A side wall section (end-section side surface) 211i of the end portion on the upstream side of the horizontal passage 211 is formed in a curved shape that is curved in the plane shown in
That is, in the horizontal passage 211, two side surfaces (side-section side surfaces) 211a and 211b extending along the fuel flow direction have a linear section, and the side wall section 211i formed between the two side-section side surfaces 211a and 211b on the upstream side has a curved section connected to the linear section of the side-section side surfaces 211a and 211b.
This side wall section 211i is connected to the side-section side surfaces 211a and 211b at the place shown by a point 210P1. The side wall section 211i is formed with a fixed curvature (that is, a fixed curvature radius R) in a range between the end portion of the side wall section 211i which is connected to the side-section side surface 211a and the end portion of the side wall section 211i which is connected to the side-section side surface 211b. In addition, in the present embodiment, the side-section side surface 211a and the side-section side surface 211b of the horizontal passage 211 are parallel to each other from the upstream end side to the downstream end side. The diameter of the semicircle forming the side wall section 211i is therefore equal to the distance between the side-section side surface 211a and the side-section side surface 211b, that is, equal to the passage width of the horizontal passage 211.
In addition, for example, the side-section side surface 211a and the side-section side surface 211b can be formed such that the distance therebetween decreases or increases from the upstream end side toward the downstream end side.
The fuel inlet 300 is formed in a circular shape having a center on the central axis 1a of the valve. That is, the passage sectional shape of the fuel inlet 300 has a circular shape. In a plan view of
In this way, when the fuel inlet 300 and the horizontal passage 211 are projected onto a plane perpendicular to the central axis 1a of the valve, the projected line of the linear section of the side-section side surfaces 211a and 211b of the horizontal passage 211 extends to the place intersecting the projected line of the opening edge of the fuel inlet 300, and the upstream-side end portion of the horizontal passage 211 extends toward the inside of the opening edge.
Moreover, in the present embodiment, a distance dimension L1 which is substantially larger than 0 (zero) is provided between the point 210P1 and the point 210P2. The distance dimension L1 of each of a plurality of the horizontal passages 211-1, 211-2, 211-3 and 211-4 may be different from each other. However, each of the all horizontal passages 211-1, 211-2, 211-3 and 211-4 has the distance dimension L1 substantially larger than 0 (zero).
In a plan view shown in
The side wall section 211i of the upstream-side end portion of the horizontal passage 211 is not necessary to have a semicircular shape, and, for example, it may has a shape in which a linear section 211ic connects a curved section 211ia connected to the side-section side surface 211a and a curved section 211ib connected to the side-section side surface 211b. That is, it may have a shape in which the linear section 211ic is connected to the side-section side surfaces 211a and 211b by chamfered sections having rounded shapes, or may have another shape. However, the horizontal passage 211 is configured on the premise that the side-section side surfaces 211a and 211b are formed in a linear shape and a shape section in which a passage width W211 decreases toward the upstream side is included on the upstream sides of the side-section side surfaces 211a and 211b.
In the present variation, only the shapes of the curved section 211ia, the curved section 211ib and the linear section 211ic are different from those of the above-mentioned embodiment, and the other configuration is formed similar to the above-mentioned embodiment.
The fuel inlet 300 is formed in the valve seat member 15, and the swirl passages 210 are formed in the nozzle plate 21n. In case where the valve seat member 15 and the nozzle plate 21n are accurately machined without an error, and both of them are accurately attached to each other without an error, the passage sectional areas S1 of a plurality of the swirl passages 210 are equal to each other. However, when an error occurs in the machining of the valve seat member 15 and the nozzle plate 21n, or when an error occurs in the attachment of them, the passage sectional areas S1 of a plurality of the swirl passages 210 are different in each of the swirl passages 210, and the amount of fuel flow distributed into each of the swirl passages 210 becomes different.
With reference to
In this comparative embodiment, four sets of horizontal passages 211′ (211-1′, 211-2′, 211-3′, 211-4′) of swirl passages 210′ (210-1′, 210-2′, 210-3′, 210-4′) are connected in the vicinity of the center of the nozzle plate 21n′. Therefore the passage length of the horizontal passages 211′ becomes long, and the dead volume of the fuel passage formed on the downstream side of the valve seat becomes large. However, in this comparative embodiment, even if a positional deviation occurs between the valve seat member 15 in which the fuel inlet 300 is formed and the nozzle plate 21n′ in which the swirl passages 210′ are formed, and the fuel inlet 300 deviates to a position shown by a dotted line 300′ with respect to the nozzle plate 21n′, it is possible to equally distribute fuel to the swirl passages 210′ through the connection part of each of the swirl passages 210′ which is located on the center part of the fuel inlet 300.
In this comparative embodiment, four sets of horizontal passages 211″ (211-1″, 211-2″, 211-3″ and 211-4″) of swirl passages 210″ (210-1″, 210-2″, 210-3″ and 210-4″) are formed independently from each other on a nozzle plate 21n″. However, the opening edge (broken line part shown by a reference number 300) of the fuel inlet 300 intersects side wall sections 211a″, 211b″ and 211i″ of each of the horizontal passages 211″ at a connection place 210P1″ of the side wall sections 211a″ and 211b″ having a linear shape and the side wall sections 211i″ having a curved shape of each of the horizontal passages 211″. That is, the distance dimension L1 explained in
In this case, positional deviation occurs between the valve seat member 15 in which the fuel inlet 300 is formed and the nozzle plate 21n″ in which the swirl passages 210″ are formed, and when the fuel inlet 300 deviates to a position shown by a dotted line 300′ relative to the nozzle plate 21n″, in the swirl passages 210-2″, 210-3″ and 210-4″, the opening edge of the fuel inlet 300 intersects the side wall sections 211i″ having curved shapes of the horizontal passages 211″. In the swirl passages 210-2″, 210-3″ and 210-4″, when positional deviation occurs between the valve member 15 and the nozzle plate 21n″, the position of the opening edge of the fuel inlet 300 is shifted in the region in which the side wall sections 211i″ of the horizontal passages 211″ are formed. In this case, as compared with a case where the opening edge position of the fuel inlet 300 is shifted in the side wall sections 211a″ and 211b″ of the horizontal passages 211″, the rate of change of the passage sectional area of each of the horizontal passage 211″ which faces the fuel inlet 300 to the amount of the positional deviation between the valve seat member 15 and the nozzle plate 21n″ becomes large. Consequently, variation in the flow amount of fuel which flows to a plurality of the swirl passages 210″ becomes large.
In the present embodiment, as explained in
In the present embodiment, in case where the severest design is performed in consideration of the positional deviation between the valve seat member 15 and the nozzle plate 21n, there is a case where the distance dimension L1 explained in
That is, in a plurality of the swirl passages 210 in the present embodiment, all of the swirl passages 210-1 to 210-4 each have a distance dimension L1 equal to 0 or larger between the connection place 210P1 that is a connection place of the side-section side surfaces (linear section) 211a and 211b and the end portion side surface (curved section) 211i and the intersection place 210P2 of the projected line of the opening edge of the fuel inlet and the projected line of the linear section. Moreover, at least one swirl passage has a distance dimension L1 larger than 0 between the connection place 210P1 that is a connection place of the side-section side surfaces 211a and 211b and the curved section 211i and the intersection place 210P2 of the projected line of the opening edge of the fuel inlet and the projected line of the linear section.
All of a plurality of the horizontal passages 221-1 to 211-4 each have the distance dimension L1 larger than 0 between the connection place 210P1 and the intersection place 210P2, and consequently, it is possible to allow for a margin of machining accuracy of the nozzle plate 12n and the valve seat member 15, and to allow for a margin of assembling accuracy in an assembling process between the nozzle plate 21n and the valve member 15.
In addition, by setting the size of the passage sectional area S1 to be larger than that of the passage sectional area S2, fuel can be distributed into each of the swirl passages 210, and thereby variation in the flow amount of the fuel flowing to each of the swirl passages 210 can be small.
In the present embodiment, a configuration has been explained in which the horizontal passages 211 are provided radially outward from the center 21no side of the nozzle plate 21n toward outside. Other than this configuration, a configuration may be applied, configuration in which the horizontal passages 211 extend from the outer circumferential side of the nozzle plate 21n toward the center 21n, and the swirl chambers 212 are connected to the end portions of the horizontal passages 211 located at the center 21no side of the nozzle plate 21n. In this case, it is also configured such that the relation between the point 210P1, the point 210P2 and the distance dimension L1 explained in
An internal combustion engine on which a fuel injection valve according to the present invention is mounted will be explained with reference to
An engine block 101 of an internal combustion engine 100 is formed with a cylinder 102, and an intake port 103 and an exhaust port 104 are provided at the top part of the cylinder 102. The intake port 103 is provided with an intake valve 105 that opens and closes the intake port 103, and the exhaust port 104 is provided with an exhaust valve 106 that opens and closes the exhaust port 104. An intake pipe 108 is connected to an inlet side end part 107a of an intake flow passage 107 communicating to the intake port 103.
A fuel pipe 110 is connected to the fuel supply port 2 (see
The intake pipe 108 is formed with an attaching part 109 for the fuel injection valve 1, and the attaching part 109 is formed with an insertion port 109a into which the fuel injection valve 1 is inserted. The insertion port 109a penetrates to the inner wall surface of the intake pipe 108 (intake flow passage), and the fuel injected from the fuel injection valve 1 inserted into the insertion port 109a is injected into the intake flow passage. In a case of two-directional spray, in an internal combustion engine in which two intake ports 103 are provided in the engine block 101, fuel injection sprays are injected toward the respective intake ports 103 (intake valves 105).
In addition, the present invention is not limited to the above embodiment or variation, and a part of the configuration can be deleted and another configuration which is not described can be added. Moreover, the configurations described in the explanation of the above-mentioned embodiment and variation can be exchanged and added between the embodiment and the variation.
As a fuel injection valve based on the embodiment explained above, for example, the following aspects can be considered.
In a preferable aspect, a fuel injection valve includes: fuel injection holes configured to inject fuel to an outside; a valve body configured to open and close a fuel passage in cooperation with a valve seat, on upstream sides of the fuel injection holes; a valve seat member formed with the valve seat; and a nozzle plate in which a plurality of swirl passages are formed and which is connected to a distal end surface of the valve seat member, wherein the swirl passages each include: a swirl chamber for allowing fuel to be swirled to flow to a corresponding one of the fuel injection holes; and a horizontal passage which is connected to an upstream side of the swirl chamber and which supplies fuel to the swirl chamber, wherein the valve seat member is opened to the distal end surface to which the nozzle plate is connected and includes a fuel inlet which is connected to an upstream-side end portion of the horizontal passage and introduces fuel into the plurality of the swirl passages, wherein the horizontal passage includes two side-section side surfaces extending along a fuel flow direction and having a linear section, and includes, on an upstream side thereof, an end-section side surface which is formed between the two side-section side surfaces and which has a curved section connected to the linear section, wherein when the fuel inlet and the horizontal passage are projected onto a plane perpendicular to a valve axial center, a projected line of the linear section of the side-section side surfaces of the horizontal passage extends to a place intersecting a projected line of an opening edge of the fuel inlet, and the upstream-side end portion of the horizontal passage extends toward an inside of the opening edge, and wherein, in the plurality of the swirl passages, all of the swirl passages each have a distance dimension equal to 0 or larger between a connection place of the linear section and the curved section and the intersection place of the projected line of the opening edge of the fuel inlet and the projected line of the linear section, and at least one of the swirl passages has a distance dimension larger than 0 between the connection place of the linear section and the curved section and the intersection place of the projected line of the opening edge of the fuel inlet and the projected line of the linear section.
In a preferable aspect of the fuel injection valve, a passage sectional area of the horizontal passage facing the fuel inlet and connected to the fuel inlet is larger than a passage sectional area formed at the linear section of the side-section side surfaces of the horizontal passage of each of the swirl passages.
In another preferable aspect, in any of the aspects of the fuel injection valve, a shape of the fuel inlet which is projected onto the plane is a circular shape, and the upstream-side end portions of a plurality of the horizontal passages forming the plurality of the respective swirl passages are located at an equal distance from a center of the nozzle plate.
In another preferable aspect, in any of the aspects of the fuel injection valve, all of the plurality of the swirl passages each have the distance dimension larger than 0 between the connection place and the intersection place.
In another preferable aspect, in any of the aspects of the fuel injection valve, the curved section formed at the end-section side surface of each of the horizontal passages has a semicircular shape which connects the two side-section side surfaces.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-049221 | Mar 2016 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/005642 | 2/16/2017 | WO | 00 |
