Fuel injector

Abstract

The object of the present invention is to provide a fuel injection valve that can suppress a decrease in the homogeneity of the fuel spray. [Solution] The fuel injector of the present invention comprises a fuel injection port and a swirling passage provided upstream of the fuel injection port for supplying swirling fuel to the fuel injection port, and is a fuel injector 1 that injects a deflected spray whose cross-sectional shape is deviated from a circle, wherein the peak distribution rate, which is the fuel distribution rate of the fuel distribution peak in the cross-section of the fuel spray, has a change characteristic with respect to the nozzle diameter of the fuel injection port that has a turning point P1, and the change characteristic decreases by a first rate of change Rc1 in the range where the nozzle diameter is less than or equal to the turning point P1, and has a second rate of change Rc2 with an absolute value smaller than the absolute value of the first rate of change Rc1 in the range where the nozzle diameter is greater than or equal to the turning point P1, and the nozzle diameter is set to a size in the range greater than or equal to the turning point P1.

Description

Technical Field

[0001] The present invention relates to a fuel injection valve that generates swirling fuel upstream of a fuel injection hole and injects the swirling fuel from the fuel injection hole.

Background Art

[0002] Patent Document 1 discloses a fuel injection valve provided with a plurality of swirling passages that inject a deflected spray having a major axis Ax1 and a minor axis Ax2 in a spray cross section. Compared with the case where the lateral passage of the swirling passage is configured as a linear passage, the first deflected spray, the second deflected spray, and the third deflected spray injected from the swirling passage are arranged so that the distribution density of fuel at the center of the entire spray cross section including these deflected sprays is reduced (see the abstract).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the production of a fuel injection valve, it is necessary to suppress variations in the homogeneity of fuel spray. Production variations in the diameter of the fuel injection hole cause variations in the homogeneity of fuel spray.

[0005] An object of the present invention is to provide a fuel injection valve capable of suppressing a decrease in the homogeneity of fuel spray.

Means for Solving the Problems

[0006] To achieve the above object, the fuel injection valve of the present invention includes a fuel injection hole and a swirling passage provided upstream of the fuel injection hole for supplying swirling fuel to the fuel injection hole, and is a fuel injection valve that injects a deflected spray whose cross-sectional shape deviates from a circular shape. The peak distribution rate, which is the fuel distribution rate of the fuel distribution peak in the fuel spray cross-section, has a change characteristic with respect to the nozzle diameter of the fuel injection hole that has a bending point. The aforementioned change characteristics are such that the nozzle diameter decreases at a first rate of change in the range below the bending point, and the nozzle diameter has a second rate of change with an absolute value smaller than the absolute value of the first rate of change in the range above the bending point. The nozzle diameter is set to a size that is greater than or equal to the bending point. [Effects of the Invention]

[0007] According to the present invention, a decrease in the homogeneity of the fuel spray can be suppressed in a fuel injection valve. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing a cross-section along the valve axis (central axis) 1a of the fuel injection valve 1 according to the present invention. [Figure 2] This is a cross-sectional view (corresponding to the cross-sectional view taken along arrow II-II in Figures 3A and 3B) showing an enlarged view of the valve portion 7 and the vicinity of the fuel injection portion 21 (nozzle portion) of the fuel injection valve 1 in Figure 1. [Figure 3A] This is a plan view of the nozzle plate 21n as seen from the direction of arrow III-III in Figure 1. [Figure 3B] This is a plan view from the direction of arrow III-III in Figure 1, showing an example of a modification to the nozzle plate 21n. [Figure 4] This is a plan view showing an enlarged view of the swivel chamber 212 and the fuel injection port 220 (an enlarged plan view of section IV shown in Figures 3A and 3B). [Figure 5] This is a plan view of the rotating passage 210, as seen from above the upper end surface of the nozzle plate 21n, on which the rotating passage 210 is formed. [Figure 6] This is a conceptual diagram showing the form of the fuel spray injected from the swivel passages 210-1 to 210-4. [Figure 7] This figure shows the fuel distribution rate for fuel sprays SPS1 and SPS4 injected from the swivel passages 210-1 to 210-4. [Figure 8] This figure shows the change in the spray inclination angle θSPS when the swirling chamber center diameter, flow path width, swirling chamber diameter, nozzle diameter, and flow path height are changed. [Figure 9] This is an explanatory diagram of the swirl chamber center diameter, flow path width, swirl chamber diameter, and nozzle diameter. [Figure 10] This figure shows the change in fuel distribution ratio at the fuel spray peak when the nozzle diameter is changed. [Figure 11] This is a cross-sectional view of an internal combustion engine equipped with fuel injection valves. [Modes for carrying out the invention]

[0009] Examples of the present invention will be described with reference to Figures 1 to 11.

[0010] The overall configuration of the fuel injection valve 1 will be explained using Figure 1. Figure 1 is a cross-sectional view showing a cross-section along the valve axis (central axis) 1a of the fuel injection valve 1 according to the present invention.

[0011] In this embodiment, the central axis 1a of the fuel injection valve 1 coincides with the axis (valve axis) of the movable element 27 on which the valve body 17 (described later) is integrally attached, and coincides with the central axis of the cylindrical body 5 (described later). Furthermore, the central axis 1a also coincides with the centerlines of the valve seat 15b and nozzle plate 21n (described later). In the following description, the central axis, axis (valve axis), and centerline will not be distinguished and will be referred to simply as the central axis 1a.

[0012] The fuel injection valve 1 is provided with a cylindrical body 5 made of a metal material extending from the upper end to the lower end. A fuel passage 3 is configured inside the cylindrical body 5 along the substantially central axis 1a. In FIG. 1, the upper end (upper end side) will be referred to as the base end (base end side), and the lower end (lower end side) will be referred to as the tip end (tip end side). The terms base end (base end side) and tip end (tip end side) are based on the flow direction of the fuel or the attachment structure to a fuel pipe not shown. That is, in the flow direction of the fuel, the base end is the upstream side and the tip end is the downstream side. Also, the vertical relationship described in this specification is defined based on FIG. 1 and has no relation to the vertical direction in the state where the fuel injection valve 1 is mounted on an internal combustion engine.

[0013] A fuel supply port 2 is provided at the base end of the cylindrical body 5. A fuel filter 13 is attached to the fuel supply port 2. The fuel filter 13 is a member for removing foreign substances mixed in the fuel.

[0014] An O-ring 11 is disposed at the base end of the cylindrical body 5. The O-ring 11 functions as a sealing material when the fuel injection valve 1 is connected to the fuel pipe.

[0015] At the tip end of the cylindrical body 5, a valve portion 7 composed of a valve body 17 and a valve seat member 15 is formed. The valve seat member 15 has a stepped valve body accommodation hole 15a for accommodating the valve body 17. A conical surface is formed in the middle of the valve body accommodation hole 15a, and a valve seat (sealing portion) 15b is formed on this conical surface. A guide surface 15c for guiding the movement of the valve body १७ along the direction of the central axis 1a is formed in the portion of the valve body accommodation hole 15a on the upstream side (base end side) of the valve seat 15b. The valve seat 15b and the valve body 17 cooperate to open and close the fuel passage. When the valve body 17 abuts against the valve seat 15b, the fuel passage is closed. Also, when the valve body 17 is separated from the valve seat 15b, the fuel passage is opened.

[0016] The valve seat member 15 is inserted into the inner side of the tip of the cylindrical body 5 and fixed to the cylindrical body 5 by a laser-welded portion 19. Laser welding of the laser-welded portion 19 is performed from the outer circumference of the cylindrical body 5 all the way around. The valve body housing hole 15a penetrates the valve seat member 15 in a direction along the central axis 1a. A nozzle plate 21n is attached to the lower end surface (tip surface) of the valve seat member 15. The nozzle plate 21n is attached so as to close the opening of the valve seat member 15 formed by the valve body housing hole 15a.

[0017] In this embodiment, a fuel injection unit 21 that injects swirling fuel is configured by a valve seat member 15 and a nozzle plate 21n. The nozzle plate 21n is fixed to the valve seat member 15 by a laser welded joint 23. The laser welded joint 23 surrounds the injection hole forming region where fuel injection holes 220-1, 220-2, 220-3, 220-4 (see Figure 3A) are formed, and encircles this injection hole forming region. The valve seat member 15 may be press-fitted into the inner side of the tip side of the cylindrical body 5 and then fixed to the cylindrical body 5 by laser welding.

[0018] In this embodiment, the valve body 17 is a ball valve with a spherical shape. Therefore, multiple notched surfaces 17a are provided at circumferential intervals on the portion of the valve body 17 facing the guide surface 15c. The notched surfaces 17a form a gap between them and the inner circumferential surface of the valve seat member 15. This gap constitutes the fuel passage. It is also possible to construct the valve body 17 using something other than a ball valve. For example, a needle valve may be used.

[0019] In this embodiment, the valve section 7, including the valve seat member 15 and the valve body 17, and the nozzle plate 21n constitute the nozzle section for injecting fuel. The nozzle plate 21n, which has fuel injection holes 220-1, 220-2, 220-3, 220-4 (see Figures 3A and 3B) and swivel passages 210-1, 210-2, 210-3, 210-4 (see Figures 3A and 3B) formed thereon, is joined to the tip surface of the nozzle section body (valve seat member 15) on which the valve section 7 is formed. The rotating passages 210-1, 210-2, 210-3, and 210-4 consist of lateral passages 211-1, 211-2, 211-3, and 211-4 (see Figures 3A and 3B) and rotating chambers 212-1, 212-2, 212-3, and 212-4 (see Figures 3A and 3B).

[0020] A drive unit 9 for driving the valve body 17 is located in the middle of the cylindrical body 5. The drive unit 9 is composed of an electromagnetic actuator. Specifically, the drive unit 9 is composed of a fixed iron core 25, a movable element (movable member) 27, an electromagnetic coil 29, and a yoke 33.

[0021] The fixed core 25 is made of a magnetic metal material and is press-fitted and fixed to the inside of the longitudinal middle portion of the cylindrical body 5. The fixed core 25 is formed in a cylindrical shape and has a through hole 25a that penetrates through its center in a direction along the central axis 1a. The fixed core 25 may be fixed to the cylindrical body 5 by welding, or it may be fixed to the cylindrical body 5 by a combination of welding and press-fitting.

[0022] The movable element 27 is positioned inside the cylindrical body 5, closer to the tip than the fixed core 25. A movable core 27a is provided at the base end of the movable element 27. The movable core 27a faces the fixed core 25 with a small gap δ between them. A small diameter portion 27b is formed at the tip end of the movable element 27, and the valve body 17 is fixed to the tip of this small diameter portion 27b by welding. In this embodiment, the movable core 27a and the small diameter portion 27b are formed as a single unit (one member made of the same material), but they may also be constructed by joining two members. The movable element 27 has a valve body 17 at its tip and displaces the valve body 17 in the direction of opening and closing the valve. The movable element 27 is guided at two points in the direction of the valve axis when moving in the direction along the central axis 1a (in the direction of opening and closing the valve), by the valve body 17 contacting the guide surface 15c of the valve seat member 15 and the outer circumferential surface of the movable core 27a contacting the inner circumferential surface of the cylindrical body 5.

[0023] A recess 27c is formed in the end face of the movable core 27a facing the fixed core 25. A spring seat 27e for the spring (coil spring) 39 is formed in the bottom surface of the recess 27c. A through hole 27f is formed on the inner circumference side of the spring seat 27e, extending along the central axis 1a to the tip end of the small diameter portion (connecting portion) 27b. An opening 27d is also formed on the side surface of the small diameter portion 27b. The through hole 27f opens in the bottom surface of the recess 27c, and the opening 27d opens in the outer circumference surface of the small diameter portion 27b, thereby forming a fuel passage 3 that connects the fuel passage 3 formed in the fixed core 25 with the valve portion 7.

[0024] The electromagnetic coil 29 is externally fitted to the outer circumference of the cylindrical body 5 at a position where the fixed core 25 and the movable core 27a face each other with a small gap δ between them. The electromagnetic coil 29 is wound around a bobbin 31 formed in a cylindrical shape from a resin material and is externally fitted to the outer circumference of the cylindrical body 5. The electromagnetic coil 29 is electrically connected to a connector pin 43 provided on a connector 41 via a wiring member 45. A drive circuit (not shown) is connected to the connector 41, and a drive current is supplied to the electromagnetic coil 29 via the connector pin 43 and the wiring member 45.

[0025] The yoke 33 is made of a magnetic metal material. The yoke 33 is positioned on the outer circumference of the electromagnetic coil 29, covering the electromagnetic coil 29, and also serves as the housing for the fuel injection valve 1. The lower end of the yoke 33 faces the outer surface of the movable core 27a via a cylindrical body 5, and together with the movable core 27a and the fixed core 25, it forms a closed magnetic path through which the magnetic flux generated by energizing the electromagnetic coil 29 flows.

[0026] A coil spring 39 is positioned in a compressed state, straddling the through-hole 25a of the fixed core 25 and the recess 27c of the movable core 27a. The coil spring 39 functions as a biasing member that biases the movable element 27 in the direction in which the valve body 17 contacts the valve seat 15b (valve closing direction). An adjuster 35 is positioned inside the through-hole 25a of the fixed core 25, and the base end of the coil spring 39 contacts the tip end face of the adjuster 35. By adjusting the position of the adjuster 35 within the through-hole 25a in the direction along the central axis 1a, the biasing force of the movable element 27 (i.e., the valve body 17) by the coil spring 39 is adjusted.

[0027] The adjuster 35 has a fuel passage 3 that penetrates its center in a direction along the central axis 1a. After the fuel flows through the fuel passage 3 of the adjuster 35, it flows into the fuel passage 3 at the tip of the through hole 25a of the fixed iron core 25, and then into the fuel passage 3 configured within the movable element 27.

[0028] An O-ring 46 is fitted to the tip of the cylindrical body 5. The O-ring 46 functions as a seal to ensure liquid-tightness and airtightness between the inner surface of the insertion port 109a (see Figure 10) formed on the internal combustion engine side and the outer surface of the yoke 33 when the fuel injection valve 1 is attached to the internal combustion engine.

[0029] A resin cover 47 is molded and covers the fuel injector 1 from the middle section to near the base end. The tip end of the resin cover 47 covers a portion of the base end of the yoke 33. The resin cover 47 also covers the wiring member 45, and the connector 41 is integrally formed by the resin cover 47.

[0030] Next, the operation of the fuel injector 1 will be explained.

[0031] When the electromagnetic coil 29 is not energized (i.e., no drive current is flowing), the movable element 27 is biased in the valve closing direction by the coil spring 39, and the valve body 17 is in contact with (seaten) the valve seat 15b. In this case, a gap δ exists between the tip end face of the fixed core 25 and the base end face of the movable core 27a. In this embodiment, this gap δ is equal to the stroke of the movable element 27 (i.e., the valve body 17).

[0032] When the electromagnetic coil 29 is energized and a drive current flows, a magnetic flux is generated in the closed magnetic circuit formed by the movable core 27a, the fixed core 25, and the yoke 33. This magnetic flux generates a magnetic attractive force between the fixed core 25 and the movable core 27a, which are facing each other across a gap δ. When this magnetic attractive force overcomes the resultant force of the biasing force from the coil spring 39 and the fuel pressure acting on the movable element 27 in the valve closing direction, the movable element begins to move in the valve opening direction. When the valve body 17 moves away from the valve seat 15b, a gap (fuel passage) is formed between the valve body 17 and the valve seat 15b, and fuel injection begins. In this embodiment, when the movable element 27 moves a distance equal to the gap δ in the valve opening direction and the movable core 27a comes into contact with the fixed core 25, the movable core 27a is stopped from moving in the valve opening direction and reaches an open, stationary state.

[0033] When the current to the electromagnetic coil 29 is cut off, the magnetic attractive force decreases and eventually disappears. When the magnetic attractive force decreases to a level smaller than the biasing force of the coil spring 39, the movable element 27 begins to move in the valve closing direction. When the valve body 17 comes into contact with the valve seat 15b, the valve body 17 closes the valve section 7 and comes to a stationary state.

[0034] Next, the structure of the valve section 7 and the fuel injection section 21 will be described in detail using Figures 2 and 3A. Figure 2 is an enlarged cross-sectional view (corresponding to the cross-sectional view taken along arrow II-II in Figures 3A and 3B) showing the vicinity (nozzle section) of the valve section 7 and fuel injection section 21 of the fuel injection valve 1 in Figure 1. Figure 3A is a plan view of the nozzle plate 21n as seen from the direction of arrow III-III in Figure 1.

[0035] The plan view in Figure 3A is a plan view of the nozzle plate 21n as seen from the fuel injection hole inlet side, and is a plan view of the upper end surface 21nu of the nozzle plate 21n. A y0-x0 coordinate system is defined on the upper end surface 21nu of the nozzle plate 21n, with mutually orthogonal y0 and x0 axes, and the center 21no of the nozzle plate 21n as the origin. The upper end surface 21nu is the surface facing the tip surface 15t of the valve seat member 15. The end surface opposite to the upper end surface 21nu is called the lower end surface 21nb.

[0036] In this embodiment, as shown in Figure 2, the nozzle plate 21n is made of a plate-like member with both end faces being flat, and the upper end face 21nu and the lower end face 21nb are parallel. That is, the nozzle plate 21n is made of a flat plate with a uniform thickness. In this embodiment, as shown in Figure 3A, the fuel injection valve 1 is configured such that the central axis 1a intersects the nozzle plate 21n at the center 21no.

[0037] The tip surface (lower end surface) 15t of the valve seat member 15 is a flat surface perpendicular to the central axis 1a. The nozzle plate 21n is joined to the tip surface 15t of the valve seat member 15, and the tip surface 15t is in contact with the upper end surface 21nu of the nozzle plate 21n.

[0038] As shown in Figure 3A, the nozzle plate 21n has lateral passages 211-1, 211-2, 211-3, 211-4, swirl chambers 212-1, 212-2, 212-3, 212-4, and fuel injection holes 220-1, 220-2, 220-3, 220-4. The lateral passages 211-1, 211-2, 211-3, 211-4 and the swirl chambers 212-1, 212-2, 212-3, 212-4 constitute swirl passages 210-1, 210-2, 210-3, 210-4 for imparting a swirl force to the fuel upstream of the fuel injection holes 220-1, 220-2, 220-3, 220-4. The four sets of swivel passages 210-1, 210-2, 210-3, and 210-4, and the fuel injection ports 220-1, 220-2, 220-3, and 220-4 are all similarly configured, and therefore may be described without distinction as "swivel passage 210," "lateral passage 211," "swivel chamber 212," and "fuel injection port 220." If the configuration differs in each set, it will be explained accordingly.

[0039] As shown in Figure 2, the valve seat member 15 has a conical valve seat 15b that tapers towards the downstream side. The downstream end of the valve seat 15b is connected to the fuel inlet 300. The downstream end of the fuel inlet 300 opens onto the tip surface 15t of the valve seat member 15. The fuel inlet 300 constitutes a fuel passage that introduces fuel into the swivel passage 210.

[0040] The swivel passage 210 is provided with the upstream end of the lateral passage 211 facing the opening of the fuel inlet 300 in order to receive fuel from the fuel inlet 300. In this embodiment, as shown in Figure 3, the four sets of lateral passages 211-1, 211-2, 211-3, and 211-4 are configured to communicate at their upstream ends, but each of the lateral passages 211-1, 211-2, 211-3, and 211-4 may be configured independently.

[0041] In Figure 2, the nozzle plate 21n, which is made of a single plate-like member, has all of the lateral passage 211, the swivel chamber 212, and the fuel injection holes 220 formed on it. The nozzle plate 21n can be made of multiple plates, for example, by dividing it in the thickness direction. For example, the lateral passage 211 and the swivel chamber 212 may be formed on one plate, and the fuel injection holes 220 may be formed on another plate. These two plates can then be stacked to form the nozzle plate 21n.

[0042] Furthermore, in this embodiment, as shown in Figure 2, the fuel injection holes 220 are formed parallel to the central axis 1a, but they may be inclined with respect to the central axis 1a. By varying the direction of inclination, fuel may be injected in multiple directions.

[0043] In this embodiment, the nozzle plate 21n is configured with a total of four sets of swirling passages 210 and fuel injection holes 220. Each of the four sets of fuel passages is formed from the center 21no side of the nozzle plate 21n toward the outer periphery. That is, the lateral passage 211 is provided from the center 21no side of the nozzle plate 21n toward the outer periphery, with a curved passage section in the middle. Furthermore, each fuel passage is formed at a 90° angle interval in the circumferential direction.

[0044] The number of swivel passages 210 and fuel injection holes 220 is not limited to four sets; there may be two or three sets, or five or more sets. Alternatively, there may be only one set of swivel passages 210 and fuel injection holes 220.

[0045] Figure 3B is a plan view taken from the direction of arrow III-III in Figure 1, showing an example of a modification to the nozzle plate 21n.

[0046] In Figure 3A, the inner circumferential wall of the slewing chamber 212 is formed with the same radius throughout its entire circumferential direction. In contrast, Figure 3B shows an example of a modification in which the radius of the inner circumferential wall of the slewing chamber 212 decreases from the upstream side to the downstream side. The inner circumferential wall of the slewing chamber 212 is not limited to the configuration shown in Figure 3A, but may also be configured as shown in Figure 3B. The characteristics of the inner circumferential wall of the slewing chamber 212 in Figures 3A and 3B are described in detail in Figure 4.

[0047] Referring to Figure 4, the configuration of the slewing chamber 212 and the fuel injection port 220 will be described in detail. Figure 4 is an enlarged plan view of the slewing chamber 212 and the fuel injection port 220 (an enlarged plan view of section IV shown in Figures 3A and 3B).

[0048] First, the configuration shown in Figure 3A will be explained. In Figure 4, a y1-x1 coordinate system is defined, having mutually orthogonal y1 and x1 axes, with the origin being the center O2 of the inlet opening 220i of the fuel injection port 220. In this embodiment, the center O2 of the inlet opening 220i of the fuel injection port 220 coincides with the center O1 of the slewing chamber 212, so the origin of the y1-x1 coordinate system coincides with the center O1 of the slewing chamber 212. The x1 axis coincides with the side wall 211i and its extension 211il.

[0049] The lateral passage 211 is connected to the slewing chamber 212 so as to be offset from the center O1 of the slewing chamber 212. One side wall 211o of the lateral passage 211 is connected to the inner circumferential wall portion (start end of the inner circumferential wall, upstream end) 212cs located on the upstream side in the direction of slewing fuel flow, and the other side wall 211i is connected to the inner circumferential wall portion (end end of the inner circumferential wall, downstream end) 212ce located on the downstream side. Therefore, an opening 212co is formed in the inner circumferential wall (side wall) 212c of the slewing chamber 212 at the connection point of the lateral passage 211.

[0050] The inner circumferential wall 212c of the swirling chamber 212 is formed in a circular (arc-shaped) manner around the inlet opening 220i of the fuel injection hole 220, so as to swirl the fuel that flows into the swirling chamber 212 from the lateral passage 211. In other words, a swirling fuel passage (swirling passage) 212d is formed between the inner circumferential wall 212c of the swirling chamber 212 and the inlet opening 220i of the fuel injection hole 220.

[0051] The side walls (sides) 211o, 211i and bottom surface 211b of the lateral passage 211 are made of nozzle plates 21n. The top surface (ceiling surface) 211u (see Figure 2) of the lateral passage 211 is made of the lower end surface 15t of the valve seat member 15.

[0052] The side wall 211o of the lateral passage 211 is connected to the slewing chamber 212 at an angle to the inner circumferential wall 212c of the slewing chamber 212. The downstream end of the side wall 211o is connected to the starting end 212cs of the inner circumferential wall 212c of the slewing chamber 212.

[0053] Furthermore, the side wall 211i of the lateral passage 211 is connected to the slewing chamber 212 at an angle that intersects with the inner circumferential wall 212c of the slewing chamber 212 or its extension. Here, "intersection" means that the side wall 211i and its extension cross the inner circumferential wall 212c or its extension. The downstream end of the side wall 211i is connected to the end portion 212ce of the inner circumferential wall 212c of the slewing chamber 212. In this embodiment, the extension of the inner circumferential wall 212c coincides with the dashed line representing the opening 212co of the slewing chamber 212.

[0054] The starting end 212cs of the inner circumferential wall 212c of the swirl chamber 212 is the end located on the upstream side in the direction of fuel swirl. The ending end 212ce of the inner circumferential wall 212c is the end located on the downstream side in the direction of fuel swirl. The ending end 212ce may have a chamfered portion such as an inclined portion or a rounded portion. In such cases, the intersection point where two imaginary lines (extension lines) extending from the inner circumferential wall 212c and the side wall 211i to the ending end 212ce intersect can be set as the ending end (downstream end) 212ce.

[0055] In this embodiment, the inner circumferential wall 212c of the swirling chamber 212 from the starting end 212cs to the ending end 212ce is formed to have an arc shape with a constant radius R centered at O1. That is, the inner circumferential wall 212c is composed of a part of the circumference of a perfect circle or a circle. On the other hand, the inlet opening 220i of the fuel injection hole 220 is circular with a radius r smaller than the radius R of the inner circumferential wall 212c of the swirling chamber 212. As a result, the bottom surface 212b of the swirling passage 212d is formed between the inlet opening edge 220ic of the fuel injection hole 220 and the inner circumferential wall 212c of the swirling chamber 212. Note that if the central axis 220a (see Figure 2) of the fuel injection hole 220 is inclined with respect to the bottom surface 212b, even if the cross-section of the fuel injection hole 220 is circular, the inlet opening 220i will not be circular but will be elliptical. In this embodiment, regardless of whether or not it is inclined, the central axis 220a of the fuel injection hole 220 (see Figure 2) is assumed to pass through the center O2 of the inlet opening 220i.

[0056] Figure 4 is a plan view in which the fuel injection port 220, the swirling chamber 212, and the lateral passage 211 are projected onto a virtual plane (projection plane) perpendicular to the central axis 1a of the fuel injection valve 1. In addition, Figure 4 shows the extension line of the side wall 211o (first extension line) 211ol and the extension line of the side wall 211i (second extension line) 211il of the lateral passage 211 projected onto the virtual plane (projection plane). The first extension line 211ol is a virtual line extended along the side wall 211o. The second extension line 211il is a virtual line extended along the side wall 211i.

[0057] The second extension line 211il divides the bottom surface of the swirling chamber 212 (the bottom surface 212b of the swirling flow path 212d) into two regions A1 and A2. Region A1 is the region located on the side wall 211o or its extension line 211ol side with respect to the second extension line 211il. The starting end 212cs of the inner circumferential wall 212c is in region A1. Region A2 is the region located on the opposite side of the side wall 211o or its extension line 211ol side with respect to the second extension line 211il. Region A2 is composed of the swirling flow path portion on the terminal end 212ce side of the inner circumferential wall 212c. Note that regions A1 and A2 do not include the line of the second extension line 211il.

[0058] The fuel injection port 220 is positioned such that a portion of its inlet opening edge 220ic extends beyond the second extension line 211il and protrudes towards region A1. That is, a portion of the inlet opening 220i of the fuel injection port 220 opens towards region A1 and is located on the extension of the lateral passage 211. If the region of the bottom surface 212b of the swirling chamber 212, located between the second extension line 211il and the side wall 211o or its extension line 211ol, is considered to be the bottom surface 211b of the lateral passage 211, then a portion of the inlet opening 220i of the fuel injection port 220 is located on the bottom surface 211b of the lateral passage 211. With this configuration, the cross-sectional shape of the fuel spray injected from the fuel injection port 220 is deformed from a circular shape to a flattened shape. In this embodiment, the cross-sectional shape of the fuel spray is an ellipse having a major axis and a minor axis.

[0059] In the following description, the cross-section and cross-sectional shape of the fuel spray refer to the cross-section and cross-sectional shape perpendicular to the injection direction, and in cases where it is particularly clear, they may be referred to as the perpendicular cross-section and perpendicular cross-sectional shape. In this embodiment, the fuel spray (overall spray) injected from the multiple fuel injection holes 220 will be described as being injected in a direction along the central axis 1a of the fuel injection valve 1.

[0060] In this embodiment, the center O2 of the inlet opening 220i of the fuel injection hole 220 is located on the second extension line 211il. Therefore, the inlet opening 220i of the fuel injection hole 220 extends beyond the second extension line 211il by the radius r of the fuel injection hole 220, into the region A1 side. As a result, the inlet opening edge 220ic of the fuel injection hole 220 intersects the second extension line 211il at two points 220ia and 220ib. That is, the inlet opening 220i of the fuel injection hole 220 is positioned such that the inlet opening edge 220ic intersects the second extension line 211il at two points 220ia and 220ib. Note that the amount of overhang of the inlet opening 220i into the region A1 side is not limited to the size of the radius r of the fuel injection hole 220. This overhang may be larger or smaller than the radius r. By changing the amount of overhang, the shape and size of the spray cross-section (spray distribution) can be changed.

[0061] Furthermore, the center O2 of the inlet opening 220i of the fuel injection hole 220 may be positioned offset from the center O1 of the swirling chamber 212 in the direction along the second extension line 211il. In other words, the center O2 of the inlet opening 220i of the fuel injection hole 220 may be eccentric with respect to the center O1 of the swirling chamber 212. By changing this amount of eccentricity, the shape and size of the spray cross-section (spray distribution) can be changed.

[0062] In this embodiment, the side walls 211o and 211i of the lateral passage 211 are formed parallel to each other, and the width of the lateral passage 211 is constant. Shifting the center O2 of the inlet opening 220i of the fuel injection hole 220 in the direction along the second extension line 211il from the center O1 of the swirling chamber 212 means shifting it in the direction along the center line L3 of the lateral passage 211.

[0063] In this embodiment, the inner circumferential wall 212c of the swivel chamber 212 is not limited to having a constant radius R. As shown in the modified example in Figure 3B, the inner circumferential wall 212c of the swivel chamber 212 may have a shape such that R decreases from the upstream side to the downstream side in the direction of fuel swivel. In the modified example in Figure 3B, the inner circumferential wall 212c of the swivel chamber 212 has the shape shown by the dashed line 212c' in its upstream portion, and is composed of an arc with a larger radius than the downstream portion. As a result, the inner circumferential wall 212c of the swivel chamber 212 is composed of an arc portion with radius R (the portion above the second extension line 211il) and an arc portion with a radius larger than R (the portion of the dashed line 212c'), and has a shape in which the radius decreases from the upstream side to the downstream side in the direction of fuel swivel.

[0064] In this case, the side wall 211o of the lateral passage 211 will be arranged as shown by the dashed line 211o' and will be connected to the inner circumferential wall 212c' at point 212cs'.

[0065] In Figure 3B, the swivel chamber 212 has a shape in which the radius of the inner circumferential wall 212c decreases in two stages from the upstream side to the downstream side. However, the radius of the inner circumferential wall 212c may also decrease continuously from the upstream side to the downstream side, for example, in a helical shape.

[0066] Referring to Figure 5, the configuration of the lateral passage 211 of the swivel passage 210 will be described. Figure 5 is a plan view of the swivel passage 210 when the upper end surface of the nozzle plate 21n on which the swivel passage 210 is formed is viewed from above. In this embodiment, the four sets of swivel passages 210-1 to 210-4 described above are formed similarly, so as mentioned above, the four sets of swivel passages 210-1 to 210-4 will not be distinguished here and will be described as the swivel passage 210.

[0067] The swivel passage 210 is located upstream of the fuel injection port 220 and supplies swivel fuel to the fuel injection port 220.

[0068] The lateral passage 211 has a curved passage section 2113 in the middle of extending from the center 21no side of the nozzle plate 21n to the outer circumference side. That is, the lateral passage 211 comprises a straight section (inner circumference straight section) 2111 formed on the center 21no side of the nozzle plate 21n, a straight section (outer circumference straight section) 2112 formed on the outer circumference side relative to the inner circumference straight section 2111, and a curved passage section 2113 formed between the inner circumference straight section 2111 and the outer circumference straight section 2112. The "inner circumference straight section 2111" may be referred to as the "inner circumference passage section 2111," and the "outer circumference straight section 2112" may be referred to as the "outer circumference passage section 2112" in the explanation.

[0069] The inner circumferential passage portion 2111 is positioned on the inner circumferential side of the nozzle plate 21n and extends radially outward. The outer circumferential passage portion 2112 extends in a direction inclined with respect to the inner circumferential passage portion 2111, so that the connection portion with the swivel chamber 212 is located radially inward, compared to the case where the inner circumferential passage portion 2111 is extended radially outward in the same manner.

[0070] In other words, the swirling passage 210 comprises a swirling chamber 212 provided upstream of the fuel injection port 220 for swirling the fuel, and a lateral passage 211 connected to the swirling chamber 212. The lateral passage 211 comprises an inner circumferential passage portion 2111 arranged on the inner circumferential side and extending radially outward, an outer circumferential passage portion 2112 extending in a direction inclined with respect to the inner circumferential passage portion 2111 such that the connection portion with the swivel chamber 212 is located radially inward compared to the case where the inner circumferential passage portion 2111 is extended radially outward, and a curved passage portion 2113 provided between the inner circumferential passage portion 2111 and the outer circumferential passage portion 2112.

[0071] In this case, the swivel chamber 212 is positioned to protrude radially outward from the outer peripheral passage portion 2112.

[0072] The curved passage section 2113 changes the extension direction of the outer-circumferential straight section 2112 to a direction inclined from the extension direction of the inner-circumferential straight section 2111. That is, the curved passage section 2113 changes the extension direction of the outer-circumferential straight section 2112 (the axial direction of the central axis 211Ax2) to a direction inclined by an angle θ211 with respect to the extension direction of the inner-circumferential straight section 2111 (the axial direction of the central axis 211Ax1). The curved passage section 2113 may be formed so that the outer-circumferential straight section 2112 bends away from the inner-circumferential straight section 2111, or it may be formed so that the outer-circumferential straight section 2112 changes direction smoothly away from the inner-circumferential straight section 2111. When expecting a rectifying effect in the lateral passage 211, it is preferable to form the lateral passage 211 such that the outer circumferential straight section 2112 changes direction smoothly from the inner circumferential straight section 2111, and it is preferable to have a curved center line 211Ax3 near the intersection point 211x where the central axis 211Ax1 and the central axis 211Ax2 intersect.

[0073] In Figure 4 described above, the outer linear section 2112 is shown, and the swivel chamber 212 and the swivel passage 210 on the fuel injection port 220 side are depicted. The central axis 211Ax2 in Figure 5 corresponds to the center line L3 of the lateral passage 211 in Figure 4.

[0074] Referring to Figure 6, the form of the fuel spray injected from the swirling passage 210 in this embodiment will be described. Figure 6 is a conceptual diagram showing the form of the fuel spray injected from swirling passages 210-1 to 210-4. Figure 6 shows a cross-section of the fuel spray perpendicular to the injection direction of the overall spray SPH (in this embodiment, the axial direction of the central axis 1a of the fuel injector 1).

[0075] Fuel spray SPS1 is injected from the swivel passage 210-1, fuel spray SPS2 is injected from the swivel passage 210-2, fuel spray SPS3 is injected from the swivel passage 210-3, and fuel spray SPS4 is injected from the swivel passage 210-4.

[0076] The cross-sectional shape of the fuel sprays SPS1 to SPS4 injected from each of the swirling passages 210-1 to 210-4 is a flattened shape having a major axis Ax1 and a minor axis Ax2, as shown in fuel spray SPS4, and is generally an elliptical shape having a major axis Ax1 and a minor axis Ax2. In this specification, fuel sprays whose cross-sectional shape is deviated from a circle, including elliptical shapes, are referred to as deflected sprays. In this embodiment, deflected sprays other than elliptical shapes may also be included, but in the following description, we will describe fuel sprays with an elliptical spray cross-section as deflected sprays.

[0077] The orientation of the major axis Ax1 and minor axis Ax2 of the elliptical fuel spray is determined by the positional relationship between the lateral passages 211-1 to 211-4 and the swivel chambers 212-1 to 212-4 connected to these lateral passages 211-1 to 211-4. In other words, in this embodiment, the positional relationship between the lateral passages 211-1 to 211-4 and the swivel chambers 212-1 to 212-4 connected to these lateral passages 211-1 to 211-4 determines the deflection direction of the deflected spray.

[0078] In this embodiment, as shown in Figures 3A, 3B, and 5, by providing a curved passage section 2113 in the lateral passage 211, the positional relationship (arrangement) between the lateral passage 211 and the swivel chamber 212 on the nozzle plate 21n can be changed.

[0079] In other words, the fuel injection valve 1 of this embodiment comprises a valve seat 15b and a valve body 17 that cooperate to open and close the fuel passage, and a plurality of swirling passages 210 downstream of the valve seat 15b and valve body 17 that impart a swirling force to the fuel before injection. The swirling passage 210 comprises a fuel injection hole 220, a swirling chamber 212 provided upstream of the fuel injection hole 220 to swirl the fuel, and a lateral passage 211 connected to the swirling chamber 212. The swirling passage 210 injects deflected spray SPS1 to SPS4 whose cross-sectional shape is deviated from a circle, and the lateral passage 211 has a curved passage section 2113 between its upstream and downstream ends in which the direction of fuel flow changes.

[0080] This allows for changing the arrangement (orientation) of the long axis Ax1 and the short axis Ax2 of the fuel spray cross-section, thereby changing the cross-sectional shape of the fuel spray or the fuel distribution rate on the cross-section of the fuel spray.

[0081] To explain the positional relationship (arrangement) between the lateral passage 211 and the slewing chamber 212, we assume that the orientation of the slewing passage 210 is as shown by arrow AW in Figure 5. That is, arrow AW is assumed to be perpendicular to the central axis 211Ax2 and pointing in the direction away from the center of the fuel injection port 220 and away from the central axis 211Ax2.

[0082] In this embodiment, by providing curved passage sections 2113 in the lateral passages 211-1 to 211-4, the orientation AW of each swivel passage 210-1 to 210-4 on the nozzle plate 21n is changed, that is, the positional relationship (arrangement) of the lateral passage 211 and the swivel chamber 212 with respect to the nozzle plate 21n, thereby changing the arrangement of the long axis Ax1 and short axis Ax2 of the fuel spray SPS1 to SPS4 with respect to the nozzle plate 21n. This changes the arrangement of the long axis Ax1 and short axis Ax2 of the fuel spray SPS1 to SPS4 within the overall spray SPH.

[0083] In this embodiment, as shown in Figure 6, the fuel sprays SPS1 to SPS4 are arranged such that their major axis Ax1 is aligned along the circumferential direction (outer edge direction) of the overall spray SPH which forms a circle, and their minor axis Ax2 is aligned along the radial direction of the overall spray SPH which forms a circle.

[0084] In this embodiment in particular, the swivel passages 210-1 to 210-4 are formed to the same shape, including the curved passage section 2113, and are arranged at equal intervals in the circumferential direction. As a result, the two fuel sprays SPS1 and SPS3 are arranged point-symmetrically with respect to the center a0 of the overall spray SPH, and the two fuel sprays SPS2 and SPS4 are arranged point-symmetrically with respect to the center a0. Furthermore, the two fuel sprays SPS1 and SPS2 and the two fuel sprays SPS4 and SPS3 are arranged line-symmetrically with respect to the line segment passing through the center a0, point a8, and point a6. Also, the two fuel sprays SPS1 and SPS4 and the two fuel sprays SPS2 and SPS3 are arranged line-symmetrically with respect to the line segment passing through the center a0, point a5, and point a7. Here, points a5 to a8 are the intersection points where the major axes Ax1 of the fuel sprays SPS1 to SPS4 intersect, as will be described later.

[0085] Figure 7 shows the fuel distribution rate for fuel sprays SPS1 and SPS4 injected from the swivel passages 210-1 to 210-4.

[0086] In this embodiment, it is possible to suppress the overlap of the four fuel sprays SPS1 to SPS4 at the center a0 of the overall spray SPH, or to allow the fuel sprays SPS1 to SPS4 to overlap when the fuel distribution rate is low. Furthermore, even when the fuel sprays SPS1 to SPS4 overlap, it is possible to prevent the parts with high distribution rates from overlapping. As a result, the height of the peak where the fuel distribution rate is high can be reduced, and the fuel distribution rate of the fuel distribution peak in the fuel spray cross-section (hereinafter referred to as the peak distribution rate) can be reduced as shown in Figure 7. Here, the "fuel spray cross-section" is a cross-section perpendicular to the injection direction of the fuel spray.

[0087] So far, we have described a configuration having four swivel passages 210-1 to 210-4, but there may be three or two swivel passages, or there may be five or more swivel passages.

[0088] Next, we will explain the homogenization of the fuel spray with reference to Figures 8 to 10. Homogenization of the fuel distribution ratio in the fuel spray cross-section is achieved by arranging the long axis Ax1 of the flattened fuel sprays SPS1 to SPS4 along the circumferential direction (outer edge direction) of the overall spray SPH, as shown in Figure 6, thereby reducing the overlap of fuel sprays SPS1 to SPS4. This allows for homogenization of the fuel spray. In this way, by creating a fuel spray with a low peak distribution ratio, homogenization of the fuel spray can be achieved.

[0089] In Figure 6, the fuel sprays SPS1 to SPS4 are inclined at a 90° angle, with the reference point (0°) being the state in which the long axis Ax1 of each fuel spray passes through the center a0 of the overall spray SPH. That is, in Figure 6, the inclination angle of the fuel sprays SPS1 to SPS4 (hereinafter referred to as the spray inclination angle θSPS) is 90°.

[0090] Figure 8 shows the change in spray inclination angle θSPS when the swirl chamber center diameter, passage width, swirl chamber diameter, nozzle diameter, passage height, and passage rotation angle are changed. Figure 9 is an explanatory diagram of the swirl chamber center diameter, passage width, swirl chamber diameter, nozzle diameter, and passage rotation angle. The x3 axis shown in Figure 9 passes through the center of fuel injection hole 220-1 and the center of fuel injection hole 220-3, and the y3 axis passes through the center of fuel injection hole 220-2 and the center of fuel injection hole 220-4. In this embodiment, x3-y3 constitutes a Cartesian coordinate system.

[0091] Referring to Figure 9, the swivel chamber center diameter, passage width, swivel chamber diameter, nozzle diameter, and passage rotation angle will be explained. The swivel chamber center diameter is RO2, which is the radial position of the center O2 of the swivel chamber 212. The flow path width is the width dimension W211 of the lateral passage 211. The swivel chamber diameter is the diameter φ212 of the swivel chamber 212. The passage rotation angle is the angle θ211Ax2 between the central axis 211Ax2 and the x3 axis of the outer linear section 2112 (see Figure 5) of the lateral passage 211. The nozzle diameter is the diameter φ220 of the fuel injection hole 220. The passage height is the height dimension H211 of the lateral passage 211, as shown in Figure 2.

[0092] In Figure 8, the reference values ​​for the swirling chamber center diameter, flow path width, swirling chamber diameter, nozzle diameter, passage height, and passage rotation angle are set as A1, A2, A3, A4, A5, and A6, respectively. Values ​​are then shifted before and after each reference value to show the sensitivity (dimensional sensitivity) to each dimension at the spray inclination angle θSPS. The horizontal axis of Figure 8 represents the reference values ​​A1 to A6 and the values ​​before and after each reference value for the swirling chamber center diameter, flow path width, swirling chamber diameter, nozzle diameter, passage height, and passage rotation angle, while the vertical axis represents the change in spray inclination angle [°] for each reference value A1 to A6.

[0093] As shown in Figure 8, the spray inclination angle θSPS has the highest dimensional sensitivity with respect to the nozzle diameter φ220. Here, the spray inclination angle θSPS is a factor that greatly affects the overlap of fuel spray SPS1 to SPS4, i.e., the peak distribution rate.

[0094] Figure 10 shows the change in fuel distribution rate at the fuel spray peak when the nozzle diameter φ220 is varied. In Figure 10, the horizontal axis represents the change from the reference nozzle diameter [mm], where 0 [mm] represents the reference nozzle diameter. The vertical axis represents the peak distribution rate [%].

[0095] Within the range below the reference nozzle diameter, the peak distribution ratio decreases at a high rate in response to changes in nozzle diameter, while within the range above the reference nozzle diameter, the peak distribution ratio does not change much. In other words, the change in peak distribution ratio corresponding to changes in nozzle diameter has a bend point P1. In Figure 10, the reference nozzle diameter is set at this bend point P1. Here, "bend" is used not only to mean bending, but also to mean that there is a change in state.

[0096] Within the range below the nozzle diameter corresponding to the bend point P1 (reference nozzle diameter), a high peak occurs in the center of the overall spray. This is thought to be because the fuel sprays SPS1 to SPS4 injected from multiple fuel injection holes 220-1 to 220-4 overlap in the center of the overall spray SPH, causing a peak to occur in the center of the spray.

[0097] On the other hand, in the range above the nozzle diameter corresponding to the bend point P1 (reference nozzle diameter), a high peak does not occur in the center of the overall spray, but rather a peak occurs at the periphery of the overall spray. This is thought to be because the fuel sprays SPS1 to SPS4 injected from multiple fuel injection holes 220-1 to 220-4 are suppressed from overlapping in the center of the overall spray SPH, causing a peak to occur at the periphery of the overall spray SPH.

[0098] Thus, at a certain nozzle diameter (reference nozzle diameter), the region where the peak occurs changes from the center of the spray to the periphery. Therefore, the characteristic change in the peak distribution rate corresponding to the change in nozzle diameter is considered to have a bend point P1. Furthermore, the peak that occurs at the periphery of the overall spray SPH is lower than the peak that occurs at the center of the overall spray SPH. This makes it possible to stably produce fuel injectors with highly homogeneous fuel spray characteristics.

[0099] In the production of fuel injector 1, it is necessary to suppress variations in the homogeneity of the fuel spray. As mentioned above, the nozzle diameter is highly sensitive to the spray inclination angle θSPS, i.e., the peak distribution rate, and variations in nozzle diameter during production lead to variations in the homogeneity of the fuel spray. As a result, the yield of fuel injectors decreases. On the other hand, the change characteristics of the peak distribution rate have a bend point P1, and the dimensional sensitivity of the change characteristics of the peak distribution rate to the nozzle diameter decreases in the range above the bend point P1.

[0100] Therefore, in this embodiment, by setting the nozzle diameter of the fuel injection hole 220 to a range greater than or equal to the bending point P1, variations in the overlap of fuel spray SPS1 to SPS4 are suppressed, and a highly homogeneous fuel spray can be injected.

[0101] In other words, the fuel injection valve 1 of this embodiment is A fuel injector 1 comprises fuel injection holes 220-1 to 220-4 and swirling passages 210-1 to 210-4 provided upstream of the fuel injection holes 220-1 to 220-4 for supplying swirling fuel to the fuel injection holes 220-1 to 220-4, and injects deflected spray SPS1 to SPS4 whose cross-sectional shape is deviated from a circle, The peak distribution rate, which is the fuel distribution rate of the fuel distribution peak in the fuel spray cross-section, has a change characteristic with respect to the nozzle diameter φ220 of fuel injection holes 220-1 to 220-4, with a bend point P1. The change characteristics are such that in the range where the nozzle diameter φ220 is below the bending point P1, it decreases at a first rate of change Rc1, and in the range where the nozzle diameter φ220 is above the bending point P1, it has a second rate of change Rc2 with an absolute value smaller than the absolute value of the first rate of change Rc1. The nozzle diameter φ220 is set to a size that is greater than or equal to the bending point P1.

[0102] As will be described later, the fuel injector 1 is a fuel injector that injects fuel into the intake passage of an internal combustion engine. If the diameter of the fuel injection hole 220 is made too large, a large amount of fuel spray will adhere to the intake port. For this reason, there is an upper limit to the diameter of the injection hole, and this upper limit is determined by the size of the intake port of the internal combustion engine, etc., and has a finite value.

[0103] In the configuration of the fuel injector 1 of this embodiment, the change characteristic of the peak distribution rate decreases at a first rate of change Rc1 in the range where the nozzle diameter is less than or equal to the bend point P1 (first range), and changes at a second rate of change Rc2 in the range where the nozzle diameter is greater than or equal to the bend point P1 (second range). In this case, the absolute value of the second rate of change Rc2 is smaller than the absolute value of the first rate of change Rc1 (|Rc2|<|Rc1|). Note that the bend point P1 is included in both the first and second ranges because it is the endpoint of the change characteristic that changes at the first rate of change Rc1 in the direction in which the nozzle diameter increases, and also the starting point of the change characteristic that changes at the second rate of change Rc2.

[0104] Furthermore, the first rate of change Rc1 has a constant value in the range where the nozzle diameter is less than or equal to the bending point P1, and the change characteristics (data) of the peak distribution rate are approximated by a straight line (first straight line) L1 with a negative slope. The second rate of change Rc2 has a constant value in the range where the nozzle diameter is greater than or equal to the bending point P1, and the change characteristics (data) of the peak distribution rate are approximated by a straight line (second straight line) L2. The first straight line L1 and the second straight line L2 intersect at the reference nozzle diameter, forming the bending point P1. In this case, the change characteristics of the peak distribution rate represented by the first straight line L1 and the second straight line L2 take on a bent shape at the bending point P1.

[0105] In other words, the change characteristics of the peak distribution rate with respect to the nozzle diameter φ220 are such that the first rate of change Rc1 and the second rate of change Rc2 have constant values. This change characteristic can be approximated by a first straight line L1 having the first rate of change Rc1 in the range where the nozzle diameter φ220 is less than or equal to the bend point P1, and can be approximated by a second straight line L2 having the second rate of change Rc2 in the range where the nozzle diameter φ220 is greater than or equal to the bend point P1, and the first straight line L1 and the second straight line L2 are connected at the bend point P1. In this case, the second rate of change Rc2 has a negative value whose absolute value is smaller than the absolute value of the first rate of change Rc1.

[0106] Referring to Figure 11, an internal combustion engine equipped with the fuel injection valve according to the present invention will be described. Figure 11 is a cross-sectional view of an internal combustion engine equipped with the fuel injection valve 1.

[0107] An engine block 101 of the internal combustion engine 100 has a cylinder 102 formed thereon, and an intake port 103 and an exhaust port 104 are provided at the top of the cylinder 102. An intake valve 105 that opens and closes the intake port 103 is provided in the intake port 103, and an exhaust valve 106 that opens and closes the exhaust port 104 is provided in the exhaust port 104. An intake pipe 108 is connected to the inlet end 107a of an intake passage 107 formed in the engine block 101 and communicating with the intake port 103.

[0108] A fuel pipe 110 is connected to the fuel supply port 2 (see Figure 1) of the fuel injection valve 1.

[0109] A mounting portion 109 for the fuel injector 1 is formed in the intake pipe 108, and an insertion port 109a for inserting the fuel injector 1 is formed in the mounting portion 109. The insertion port 109a penetrates to the inner wall surface (intake passage) of the intake pipe 108, and the fuel injected from the fuel injector 1 inserted into the insertion port 109a is injected into the intake passage. In the case of bidirectional spray, for an internal combustion engine in which two intake ports 103 are provided in the engine block 101, each fuel spray is directed towards each intake port 103 (intake valve 105) and injected.

[0110] It should be noted that the present invention is not limited to the embodiments or modifications described above, and it is possible to delete some components or add other components not described. It is also possible to combine the configurations of the nozzle plates 21n of Embodiments 1 to 7. [Explanation of Symbols]

[0111] 1...Fuel injection valve, 210, 210-1~210-4...Swivel passage, 211...Lateral passage, 212...Swivel chamber, 220, 220-1~220-4...Fuel injection port, 2111...Inner circumferential passage section, 2112...Outer circumferential passage section, 2113...Bend passage section, L1...First straight line, L2...Second straight line, P1...Bend point, Rc1...First rate of change, Rc2...Second rate of change, SPS1~SPS4...Declining spray, φ220...Injection port diameter.

Claims

1. A fuel injection valve comprising a fuel injection port and a swirling passage provided upstream of the fuel injection port for supplying swirling fuel to the fuel injection port, wherein the fuel injection valve injects a deflected spray having a cross-sectional shape that deviates from a circle, The peak distribution rate, which is the fuel distribution rate of the fuel distribution peak in the fuel spray cross-section, has a change characteristic with respect to the nozzle diameter of the fuel injection hole that has a bending point. The aforementioned change characteristic is such that the nozzle diameter decreases at a first rate of change in the range below the bending point, and has a second rate of change with an absolute value smaller than the absolute value of the first rate of change in the range above the bending point. The nozzle diameter of the fuel injection valve is set to be larger than or equal to the size of the bending point.

2. In the fuel injection valve according to claim 1, The aforementioned change characteristics are a fuel injection valve in which the first rate of change and the second rate of change have constant values.

3. In the fuel injection valve according to claim 2, The aforementioned change characteristic can be approximated by a first straight line having the first rate of change in the range where the nozzle diameter is below the bending point, and can be approximated by a second straight line having the second rate of change in the range where the nozzle diameter is above the bending point. The first straight line and the second straight line are connected at the bending point by a fuel injection valve.

4. In the fuel injection valve according to claim 3, The second rate of change is a fuel injection valve having a negative value whose absolute value is smaller than the absolute value of the first rate of change.

5. In the fuel injection valve according to any one of claims 1 to 4, The swirling passage comprises a swirling chamber provided upstream of the fuel injection port for swirling the fuel, and a lateral passage connected to the swirling chamber. The fuel injection valve comprises a lateral passage comprising: an inner circumferential passage portion arranged on the inner circumferential side and extending radially outward; an outer circumferential passage portion extending in a direction inclined with respect to the inner circumferential passage portion such that the connection portion with the swivel chamber is located radially inward compared to the case where the inner circumferential passage portion is extended radially outward; and a curved passage portion provided between the inner circumferential passage portion and the outer circumferential passage portion.

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