Fuel injection valve

Abstract

One or more of the plurality of injection holes is a flat injection hole having a long axis (Ha) and a short axis (Hb), and the flat injection hole further includes one or more "specific flat injection holes" (131) whose long axis (Ha) is orthogonal to a plane (Sh) that includes the injection hole axis (Ho) connecting the center of the inlet opening (14) and the center of the outlet opening (15) and is parallel to the valve axis (Z), and has flat portions (157, 158) on the inner wall that face each other across the long axis (Ha), and in the inner wall on one side along which fuel flows with respect to the long axis (Ha) at the time of injection, the radius of curvature of the long axis direction end portion of the inlet opening (14) is set to a first radius of curvature (R1), the radius of curvature of the long axis direction end portion of the outlet opening (15) is set to a second radius of curvature (R2), and the ratio of the second radius of curvature (R2) to the first radius of curvature (R1), that is, the radius of curvature ratio, is in the range of 40% to 100%.

Description

[0001] Cross-referencing of related applications

[0002] This application is based on Japanese Patent Application No. 2020-120814, filed on July 14, 2020, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to fuel injection valves. Background Technology

[0004] Previously, techniques for improving spray by carefully designing the nozzle shape of a fuel injection valve were known. For example, the fuel injection valve disclosed in Patent Document 1 reduces the area of ​​the portion of the nozzle inner wall where no fuel is flowing by making the nozzle cross-section flat, thereby suppressing the accumulation of deposits on the nozzle inner wall. Furthermore, Patent Document 2 describes how making the nozzle flat promotes the thinning of the liquid film, enabling atomization and low permeability.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2017-2876

[0008] Patent Document 2: Japanese Patent Application Publication No. 2020-8013 Summary of the Invention

[0009] In the field of vehicle engine technology, the requirements for fuel injection systems have been increasing in recent years due to the stricter control of PM (particulate matter) at low temperatures. As the cause of cold PM, it is known that the wet (fuel film) adhering to the piston surface does not vaporize, and large-diameter PM particles are generated during combustion due to the luminous flame.

[0010] In previous technologies, atomization and low permeability were achieved by promoting the thinning of the liquid film by making the fuel flow along the inner wall of the flat nozzle. While atomization and low permeability can reduce the total amount of Wet on the wall, they completely ignore the relationship between the adhesion state of Wet on the wall and permeability.

[0011] Furthermore, considering a different approach than reducing the total amount of wall-mounted Wet due to low permeability, reducing permeability can be achieved by rapidly evaporating the attached fuel, thereby reducing residual fuel on the wall and suppressing the flame. To achieve rapid evaporation and reduce residual fuel, a thin and wide wall-mounted Wet adhesion is required. Therefore, it is necessary to improve the spray dispersion to reduce deviations in fuel concentration and particle size.

[0012] The purpose of this disclosure is to provide a fuel injection valve that achieves highly dispersed and highly homogeneous spray.

[0013] The fuel injection valve disclosed herein includes a nozzle, a needle, and a drive unit. The nozzle is arranged centered on a valve shaft and includes: a nozzle barrel portion forming a fuel passage on its inner side; a nozzle bottom portion sealing one end of the nozzle barrel portion; a plurality of injection holes connecting the "surface of the nozzle bottom portion on the nozzle barrel portion side" and the "surface opposite to the nozzle barrel portion side" to inject fuel in the fuel passage; and an annular valve seat formed in the "surface of the nozzle bottom portion on the nozzle barrel portion side" around the injection holes.

[0014] The needle is configured to reciprocate along the valve shaft inside the nozzle, closing the nozzle when it abuts against the valve seat and opening the nozzle when it moves away from the valve seat. The drive unit can move the needle in the valve opening or valve closing direction.

[0015] The nozzle orifice has an inlet opening formed on the "surface of the nozzle bottom on the nozzle barrel side" and an outlet opening formed on the "surface of the nozzle bottom opposite to the nozzle barrel side" with an area larger than the inlet opening. One or more of the multiple nozzle orifices are "flat nozzle orifices" with an outlet opening having a long axis and a short axis. Flat nozzle orifices also include one or more "specific flat nozzle orifices".

[0016] The long axis of a certain flat nozzle is orthogonal to a plane that includes the nozzle axis connecting the center of the inlet opening and the center of the outlet opening and is parallel to the valve axis. In addition, the certain flat nozzle has a planar portion on its inner wall that is opposed to the long axis.

[0017] During injection, the fuel flows along the inner wall of one side relative to its long axis. The radius of curvature at the long-axis end of the inlet opening is defined as the first radius of curvature, and the radius of curvature at the long-axis end of the outlet opening is defined as the second radius of curvature. The ratio of the second radius of curvature to the first radius of curvature is defined as the radius of curvature ratio. The radius of curvature ratio is in the range of 40% to 100%, more preferably in the range of 50% to 90%.

[0018] In this disclosure, by setting the radius of curvature of the outlet opening relative to the inlet opening in a flat nozzle with a flat outlet opening to a range of 40% to 100%, the liquid film forming the spray within the nozzle can be made homogeneous. Therefore, a highly dispersed and highly homogeneous spray can be achieved.

[0019] For example, multiple nozzles are symmetrically arranged with respect to a reference plane containing the valve shaft, and at least one pair of nozzles with the largest nozzle angle relative to the valve shaft constitutes a specific flat nozzle. Attached Figure Description

[0020] The foregoing and other objects, features and advantages of this disclosure will become more apparent from the following detailed description with reference to the accompanying drawings.

[0021] Figure 1 This is a cross-sectional view showing the overall structure of the fuel injection valve in this embodiment.

[0022] Figure 2 This is a schematic diagram of a side-mounted engine equipped with the fuel injection valves of embodiments 1, 6 to 9.

[0023] Figure 3 Viewed from the direction of arrow III Figure 2 The resulting image.

[0024] Figure 4 yes Figure 1 Enlarged sectional view of section IV (axial sectional view of the nozzle).

[0025] Figure 5 This is a schematic three-view diagram showing the nozzle shape (conical nozzle) of the comparative example.

[0026] Figure 6 This is a schematic three-view view showing the nozzle shape (flat nozzle) of this embodiment.

[0027] Figure 7 This is a schematic diagram showing the nozzle configuration (5 holes) of the fuel injection valve in the first embodiment.

[0028] Figure 8 yes Figure 7 Enlarged view of section VIII.

[0029] Figure 9 It is an axial cross-sectional view of the nozzle on the inner wall of one side along which the fuel is injected.

[0030] Figure 10 This is a schematic diagram showing the shape of the nozzle in the first embodiment.

[0031] Figure 11 This is a graph illustrating the homogeneity of the liquid film.

[0032] Figure 12 This is a graph showing the relationship between the radius of curvature ratio and the homogeneity of the liquid film.

[0033] Figure 13 This is a schematic diagram showing the shape of the nozzle in the second embodiment.

[0034] Figure 14 This is a schematic diagram showing the shape of the nozzle in the third embodiment.

[0035] Figure 15 This is a schematic diagram showing the nozzle shape of the fourth embodiment.

[0036] Figure 16 This is a schematic diagram showing the nozzle shape of the fifth embodiment.

[0037] Figure 17 This is a schematic diagram showing the nozzle configuration (5 holes) of the fuel injection valve in the sixth embodiment.

[0038] Figure 18 This is a schematic diagram showing the nozzle configuration (6 holes) of the fuel injection valve in the seventh embodiment.

[0039] Figure 19 This is a schematic diagram showing the nozzle configuration (6 holes) of the fuel injection valve in the eighth embodiment.

[0040] Figure 20 This is a schematic diagram showing the nozzle configuration (6 holes) of the fuel injection valve in the 9th embodiment.

[0041] Figure 21 This is a schematic diagram of a mid-mounted engine equipped with the fuel injection valves of embodiments 10 and 11.

[0042] Figure 22 This is a schematic diagram showing the nozzle configuration (5 holes) of the fuel injection valve in the 10th embodiment.

[0043] Figure 23 This is a schematic diagram showing the nozzle configuration (6 holes) of the fuel injection valve in the 11th embodiment. Detailed Implementation

[0044] Hereinafter, several embodiments of the fuel injection valve of this disclosure will be described based on the accompanying drawings. In the various embodiments, substantially the same structures will be given the same reference numerals and descriptions will be omitted. Furthermore, the embodiments including No. 1 to No. 11 will be referred to as "this embodiment". The fuel injection valve of this embodiment is mounted in an engine such as a gasoline engine and injects fuel into the combustion chamber of the engine.

[0045] [Overall structure of the fuel injection valve]

[0046] First, refer to Figures 1-4 This describes the overall structure of the fuel injection valve and the general structure of a side-mounted engine equipped with the fuel injection valves of embodiments 1 to 9. Additionally, in Figure 21 The diagram shows the structure of a mid-mounted engine equipped with the fuel injection valves of embodiments 10 and 11. These aspects are common to prior art such as Patent Documents 1 and 2, and detailed descriptions have been appropriately omitted.

[0047] Figure 2 , Figure 3The side-mounted engine 801 shown includes a cylinder block 81, a piston 82, a cylinder head 90, an intake valve 95, and an exhaust valve 96. A combustion chamber 83 is formed between the inner wall of the cylinder block 81, the wall of the cylinder head 90, and the piston 82. The volume of the combustion chamber 83 increases or decreases as the piston 82 reciprocates.

[0048] The cylinder head 90 has an intake manifold 91 and an exhaust manifold 93. An intake passage 92 is formed in the intake manifold 91 to guide intake air into the combustion chamber 83. An exhaust passage 94 is formed in the exhaust manifold 93 to guide exhaust gas generated in the combustion chamber 83 towards the atmosphere. An intake valve 95 can open and close the connection between the combustion chamber 83 and the intake passage 92. An exhaust valve 96 can open and close the connection between the combustion chamber 83 and the exhaust passage 94.

[0049] In the side-mounted engine 801, the fuel injection valve 70 is obliquely disposed on the side of the intake passage 92, on the cylinder block 81 side, i.e., on the side of the combustion chamber 83. Furthermore, a spark plug 97 is disposed between the intake valve 95 and the exhaust valve 96 on the cylinder head 90, corresponding to the center of the combustion chamber 83. The spark plug 97 is positioned so that the fuel injected from the fuel injection valve 70 does not directly adhere to it and can ignite the fuel-air mixture. Thus, engine 801 is a direct-injection gasoline engine.

[0050] The fuel injection valve 70 is configured such that a plurality of nozzles 13 are partially exposed radially outward from the combustion chamber 83. Fuel pressurized by a fuel pump (not shown) is supplied to the fuel injection valve 70. A conical fuel spray Fo is injected into the combustion chamber 83 from the plurality of nozzles 13 of the fuel injection valve 70.

[0051] The engine 801 is equipped with two intake valves 95 and two exhaust valves 96. The two intake valves 95 are respectively located at the two ends of the branches of the intake manifold 91 on the cylinder block 81 side. The two exhaust valves 96 are respectively located at the two ends of the branches of the exhaust manifold 93 on the cylinder block 81 side. The fuel injection valve 70 is mounted with its valve shaft Z along the axis including the cylinder block 81 and passing through the central section Se between the two intake valves 95 and the two exhaust valves 96.

[0052] Next, based on Figure 1 The basic structure of the fuel injection valve 70 is described below. The fuel injection valve 70 includes a nozzle 10, a housing 20, a needle 30, a movable core 37, a fixed core 41, a coil 45, and springs 42 and 43. The movable core 37, the fixed core 41, and the coil 45 function as a "drive unit" that enables the needle 30 to move in the valve opening or closing direction.

[0053] The nozzle 10 is positioned centered on the valve shaft Z and includes a nozzle barrel 11, a nozzle bottom 12, multiple nozzle holes 13, and a valve seat 17. The generally cylindrical nozzle barrel 11 forms a fuel passage 100 on its inner side. The nozzle bottom 12 seals one end of the nozzle barrel 11. The multiple nozzle holes 13 formed on the nozzle bottom 12 inject fuel into the fuel passage 100. The valve seat 17 is formed in a ring around the nozzle holes 13 on the side of the nozzle barrel 11 of the nozzle bottom 12. Details regarding the nozzle holes 13 will be described later.

[0054] The housing 20 includes a first cylindrical component 21, a second cylindrical component 22, a third cylindrical component 23, and an inlet 24. The first cylindrical component 21, the second cylindrical component 22, and the third cylindrical component 23 are all generally cylindrical components, arranged coaxially and interconnected in the order of first cylindrical component 21, second cylindrical component 22, and third cylindrical component 23. One end of the inlet 24 is connected to the end of the third cylindrical component 23, and the other end is connected to a pipe (not shown). Inside the inlet 24, a filter 25 is provided to capture foreign matter in the fuel.

[0055] A fuel passage 100 is formed inside the housing 20. Fuel flowing in from the inlet 24 passes through the fuel passage 100, through the inside of the nozzle barrel 11, and is injected from the nozzle hole 13. When the fuel injection valve 70 of this embodiment is used, the pressure of the fuel in the fuel passage 100 is assumed to be, for example, about 20 MPa.

[0056] The needle 30 is configured to reciprocate along the valve shaft Z inside the nozzle 10. The needle 30 has a needle body 301 formed in the shape of a rod, a seat portion 31, a large diameter portion 32, a protruding edge portion 34, etc. The seat portion 31 is formed at the end of the needle body 301 on the nozzle 10 side and can abut against the valve seat 17.

[0057] A large-diameter portion 32 is formed near the seat portion 31 at the end of the needle body 301 on the valve seat 17 side. The outer diameter of the large-diameter portion 32 is set to be larger than the outer diameter of the end of the needle body 301 on the valve seat 17 side. The large-diameter portion 32 is formed such that its outer wall slides against the inner wall of the nozzle barrel portion 11 of the nozzle 10. Fuel can flow through multiple circumferential notches 33 formed on the outer wall of the large-diameter portion 32. A protruding edge portion 34 is formed to protrude radially outward from the end of the needle body 301 opposite to the seat portion 31.

[0058] When the needle 30 abuts against the valve seat 17 at the seat 31, it closes the nozzle 13; when the seat 31 moves away from the valve seat 17, it opens the nozzle 13. Hereinafter, the direction in which the needle 30 moves away from the valve seat 17 is called the valve opening direction, and the direction in which the needle 30 abuts against the valve seat 17 is called the valve closing direction.

[0059] The movable core 37 is formed in a generally cylindrical shape from a magnetic material such as ferritic stainless steel that has undergone magnetic stabilization treatment. The movable core 37 is configured to be able to move axially relative to the needle body 301 inside the first cylindrical member 21 and the second cylindrical member 22 of the housing 20.

[0060] The fixed core 41 is formed into a generally cylindrical shape from a magnetic material such as ferritic stainless steel that has undergone magnetic stabilization treatment. The fixed core 41 is disposed on the inner side of the second cylindrical component 22 and the third cylindrical component 23 of the housing 20 on the inlet 24 side, relative to the movable core 37.

[0061] A cylindrical adjusting tube 54 is pressed into the inside of the fixed core 41. A spring 42, such as a helical spring, is disposed between the adjusting tube 54 inside the fixed core 41 and the protruding edge 34 of the needle 30. The spring 42, together with the needle 30, applies force to the movable core 37 in the direction of valve closure.

[0062] The coil 45 is formed in a generally cylindrical shape and is configured to surround the radially outer sides of the housing 20, particularly the second cylindrical member 22 and the third cylindrical member 23. Furthermore, a cylindrical retainer 26 is provided on the radially outer side of the coil 45 in such a way as to cover the coil 45.

[0063] When the coil 45 is energized from an external control device via terminal 48 of connector 47, a magnetic circuit is formed between the movable core 37, the first cylinder member 21, the cage 26, the third cylinder member 23, and the fixed core 41, bypassing the second cylinder member 22 which acts as a magnetic throttling section. Therefore, a magnetic attraction is generated between the fixed core 41 and the movable core 37, and the movable core 37, along with the needle 30, is attracted towards the fixed core 41. Consequently, the needle 30 moves in the valve-opening direction, and the seat 31 moves away from the valve seat 17, opening the valve. As a result, the nozzle 13 is opened, and fuel is injected from the nozzle 13. Thus, the coil 45, by being energized, attracts the movable core 37 towards the fixed core 41, causing the needle 30 to move in the valve-opening direction.

[0064] When the energization of the coil 45 is stopped while the movable core 37 is being attracted towards the fixed core 41, the needle 30 and the movable core 37 are forced towards the valve seat 17 by the force of the spring 42. As a result, the needle 30 moves towards the valve closing direction, and the seat 31 abuts against the valve seat 17 to close the valve. Consequently, the nozzle 13 is sealed.

[0065] Spring 43, for example, is a helical spring, which applies force to the movable core 37 towards the fixed core 41, i.e., in the valve opening direction. The force of spring 43 is smaller than that of spring 42. Therefore, when the coil 45 is not energized, the needle 30 is pressed against the valve seat 17 by the spring 42 and the seat 31, resulting in a closed valve state.

[0066] Fuel flowing in from the inlet 24 is guided to the nozzle 13 through the fuel passage 100 between the inner side of the fixed core 41 and the regulating pipe 54, the inner wall of the needle 30 and the housing 20, and the inner wall of the cylinder 11. In addition, when the fuel injection valve 70 is in operation, since the movable core 37 and the needle 30 are surrounded by fuel, the movable core 37 and the needle 30 can smoothly reciprocate axially inside the housing 20.

[0067] exist Figure 4 The middle represents equivalent to Figure 1 The axial section of nozzle 13 in section IV is enlarged. Additionally, in... Figure 4 The needle 30 is omitted from the illustration. The nozzle 10 has a valve seat 17 and a bag wall surface 180 on the inlet side of the nozzle orifice 13, i.e., the "surface 121 on the nozzle barrel 11 side of the nozzle bottom 12".

[0068] The valve seat 17 is formed in an annular shape around the bag wall surface 180. The valve seat 17 is formed in a conical shape as it approaches the valve shaft Z from the nozzle barrel 11 side toward the bag wall surface 180 side. The bag wall surface 180 is recessed from the center of the "face 121 on the nozzle barrel 11 side of the nozzle bottom 12" toward the side opposite to the nozzle barrel 11, forming a bag chamber 18 on the inner side. The bag chamber 18 is formed between the bag wall surface 180 and the seat portion 31 of the needle 30.

[0069] The nozzle 13 connects the bag wall surface 180, which is part of the "surface 121 on the nozzle barrel 11 side of the nozzle bottom 12", and the "surface 122 on the opposite side of the nozzle barrel 11 of the nozzle bottom 12", to inject fuel into the fuel passage 100. In addition, the bag wall surface 180 and the "surface 122 on the opposite side of the nozzle barrel 11 of the nozzle bottom 12" are formed into curved surfaces.

[0070] The nozzle 13 has an inlet opening 14 formed on the bag wall surface 180 of the side of the nozzle barrel 11 that serves as the nozzle bottom 12, and an outlet opening 15 formed on the side 122 of the nozzle bottom 12 opposite to the nozzle barrel 11. The area of ​​the outlet opening 15 is larger than the area of ​​the inlet opening 14.

[0071] The straight line connecting the center Ci of the inlet opening 14 and the center Co of the outlet opening 15 is defined as the "nozzle axis Ho". The nozzle axis Ho does not necessarily intersect the valve axis Z. Therefore, an imaginary axis Zv is imagined to intersect the nozzle axis Ho and be parallel to the valve axis Z, and the angle between the nozzle axis Ho and the imaginary axis Zv is defined as the "nozzle angle γ". Figure 4 The distance between the center Ci of the inlet opening 14 and the center Co of the outlet opening 15, as viewed in direction VII (i.e., the direction of the valve axis Z), is defined as the "inter-center projection distance P". If the nozzle length L is approximately constant, the larger the inter-center projection distance P is, the larger the nozzle angle γ is.

[0072] Furthermore, assuming the inlet opening 14 is a perfect circle, let its diameter be D. The ratio (L / D) of the nozzle length L to the inlet opening diameter D is set to 2.0 to 3.0. If (L / D) is less than 2.0, the injection direction is unstable. Furthermore, if (L / D) is greater than 3.0, the injection velocity decreases due to friction with the inner wall of the nozzle, resulting in deteriorated atomization performance.

[0073] The above is a brief description of the fuel injection valve 70 and the nozzle 13. Furthermore, ways to reduce wall wet, which is a cause of cold PM generation in the engine, include (1) reducing the amount of adhering fuel and (2) increasing the amount of evaporated fuel after adhering. Conventionally, focusing on (1) reducing the amount of adhering fuel, the nozzle shape of the fuel injection valve has been carefully designed to achieve low spray penetration. In contrast, in this embodiment, focusing on (2) increasing the amount of evaporated fuel after adhering, a preferred nozzle shape is proposed with the goal of achieving highly dispersed, highly homogeneous spray resulting in atomization and wide-angle injection.

[0074] From a broader perspective, increasing the spray diffusion rate is effective. Regarding high atomization, based on Fraser's liquid film splitting theory disclosed in Japanese Patent Application Publication No. 2002-168163, since the volume average particle size is proportional to the (1 / 3)th power of the liquid film thickness, the focus is on fuel thin film formation. Therefore, in this embodiment, the nozzle shape of the fuel injection valve is specified to increase the spray diffusion rate and achieve fuel thin film formation.

[0075] Hereinafter, the nozzle shape that satisfies the preferred conditions in this embodiment will be defined as a "specific flat nozzle". A "specific flat nozzle" refers to a nozzle among "flat nozzles" with a long axis and a short axis at the outlet opening that satisfies the specific requirements described later. In the fuel injection valve 70 of this embodiment, at least a portion of the plurality of nozzles 13 constitutes a specific flat nozzle, or all of the nozzles 13 constitute a specific flat nozzle. Next, the structure of the fuel injection valve 70 that achieves the above-mentioned objective will be described in detail according to each embodiment.

[0076] The structure of each embodiment is defined by the arrangement of multiple nozzles and the combination of the shapes of each specific flat nozzle. Regarding the various shapes of the specific flat nozzles in embodiments 1 to 5, the nozzle designation is obtained by assigning the embodiment number to the third digit after "13". Regarding the fuel injection valves with various nozzle arrangements in embodiments 1, 6 to 11, the fuel injection valve designation is obtained by assigning the embodiment number to the third digit after "70".

[0077] (First Embodiment)

[0078] Reference Figures 5-12The structure and function of the fuel injection valve 701 of the first embodiment will be explained. First, the term "flat nozzle" as a general concept of "specific flat nozzle" refers to a flat nozzle whose outlet opening is not a perfect circle but has a major axis and a minor axis. Generally, the shape of the outlet opening of a flat nozzle includes elliptical, oval, and oblong shapes as disclosed in Patent Document 2. Among them, the outlet opening 15 of the flat nozzle 131 of the first embodiment is oblong, i.e., runway-shaped, and in this specification, the nozzle with this shape is referred to as a "runway-shaped nozzle".

[0079] The antonym of "flat nozzle" is "circular nozzle" (with a perfectly round outlet opening) or "conical nozzle" (with a conical shape where the inlet and outlet openings are coaxial). Here, refer to... Figure 5 , Figure 6 The three-dimensional shapes of the conical nozzle 130 of the comparative example and the flat nozzle 131 of the first embodiment are compared and explained. Figure 5 In the conical nozzle 130 shown, the inlet opening 14 and the outlet opening 15 are circular and formed on the same axis. The expansion angle θ of the inner wall of the nozzle 130 in the cross-section including the nozzle axis Ho is constant in the circumferential direction.

[0080] exist Figure 6 The text refers to a flat nozzle, specifically a runway-shaped nozzle with an exit opening 15. Other common shapes for the exit opening of flat nozzles include, besides the oblong runway-shaped nozzle, elliptical nozzles or oval nozzles. The inlet opening 14 of the flat nozzle 131, which is a runway-shaped nozzle, is a perfect circle with a radius of R1. The exit opening 15 of the flat nozzle 131 has a major axis Ha and a minor axis Hb, and the endpoints of the arcuate portions with a radius R2 at both ends along the major axis are connected by parallel straight lines.

[0081] In the cross-section along the major axis Ha, the inner walls along the opposing minor axes expand from the inlet opening 14 toward the outlet opening 15 at an expansion angle θ. Conversely, in the cross-section along the minor axis Hb, the distance between the inner walls along the opposing major axes is constant. In other words, the expansion angle θ of the inner walls along the opposing major axes is set to 0°. This is also a specification based on the laser machinability requirements of the nozzle.

[0082] In this specification, the radius R1 of the inlet opening 14 is generally referred to as the radius of curvature of a curve other than a perfect circle, and is called the "first radius of curvature R1". Similarly, the radius R2 of the arcuate portions at both ends of the outlet opening 15 along its major axis is generally referred to as the "second radius of curvature R2". Furthermore, the ratio of the second radius of curvature R2 to the first radius of curvature R1 is defined as the radius of curvature ratio ρ (=R2 / R1). Figure 6The lower part shows shape examples of (A) ρ = 100%, (B) ρ = 50%, and (C) ρ = 0% as examples of the radius of curvature ratio ρ.

[0083] Next, refer to Figure 7 ,right Figure 4 The nozzle configuration of the fuel injection valve 701 in the first embodiment, viewed from direction VII, will be described. Figure 7 As shown, the fuel injection valve 701 of the first embodiment has five specific flat nozzles 511-515 arranged around the valve shaft Z. In the side-mounted fuel injection valve, the direction of each nozzle shaft Ho is offset to one side (lower part of the figure) relative to the valve shaft Z.

[0084] In the following diagrams illustrating the nozzle configuration, identification references, different from the general reference numeral "131" used for the nozzles in the first embodiment, are used to distinguish each nozzle according to its position. For example, reference numeral "511" refers to nozzle number 1 of the first pattern of the 5-hole specification. Furthermore, for example... Figure 23 The designation "634" refers to nozzle number 4 of style 3 in the 6-hole specification. Additionally, "No. 1," "No. 4," etc., are numbers assigned for convenience in this instruction manual.

[0085] In this specification, general reference numerals such as "131" are used when describing the shape of various parts of a nozzle with regard to a specific flat nozzle, and identification reference numerals such as "511-515" are used when describing the arrangement of multiple nozzles in the nozzle bottom 12 as a whole. Furthermore, only general reference numerals are used in the reference numerals of the claims, without specifying identification reference numerals. Figure 7 In the diagram, for the five specific flat nozzles 511-515, the nozzle axis Ho and the major axis Ha are represented, respectively. The minor axis Hb overlaps with the nozzle axis Ho. Figure 8 The enlarged view of nozzle 4 514 is shown as a representative view of the specific flat nozzle 131 in the first embodiment.

[0086] exist Figure 7 In the paper, the plane containing the valve shaft Z and represented by a single-dotted line in the vertical direction is designated as the reference plane Sy, and the plane containing the valve shaft Z and represented by a single-dotted line in the horizontal direction is designated as the reference orthogonal plane Sx. Of the five specific flat nozzles 511-515, nozzle 1 511 is positioned on the reference plane Sy, and nozzles 2 and 3 512, 513 and nozzles 4 and 514, 515 are symmetrically positioned relative to the reference plane Sy. No. 2 and 3 nozzles 512, 513 and nozzles 4 and 514, 515 are configured such that their major axis Ha extends from the opposite side of nozzle 1 511 toward the side of nozzle 1 511 and exits from the reference plane Sy.

[0087] The purpose of this nozzle configuration is to increase the spray occupancy of the target cylinder space by utilizing the coanda effect generated between the sprays from nozzles 511-515. Specifically, in the space surrounded by nozzles 511, 512, and 513 (numbers 1, 2, and 3), a negative pressure is generated in the closed space formed by the three adjacent spray chambers, and this negative pressure causes spray interference. On the other hand, in the two spray chambers, even if spray interference occurs, a closed space is not formed. Therefore, to avoid spray interference from the three spray chambers, a nozzle configuration is designed to actively cause interference between the two spray chambers, rather than the three, by utilizing the coanda effect between the two spray chambers.

[0088] The center of the inlet opening 14 of each nozzle 511-515 is arranged on a concentric circle φi centered on the valve shaft Z. Although in Figure 7 There is no direct illustration, but the nozzle angle γ of each nozzle 511-515 is as described above, and its distance from the center projection P (refer to...) Figure 4 Therefore, the nozzle angle γ of nozzle 1 (511) is the smallest, followed by nozzles 2 and 3 (512 and 513) with relatively small nozzle angle γ. Furthermore, nozzles 4 and 5 (514 and 515) have the largest nozzle angle γ.

[0089] Taking nozzle 4 (514) as an example, refer to Figure 8 The requirements for a “specific flat nozzle” will be explained. The specific flat nozzle 131 is based on the premise that it is a flat nozzle having a long axis Ha and a short axis Hb, and also has three other requirements.

[0090] As a first requirement, the major axis Ha of the specific flat nozzle 131 is orthogonal to the plane Sh, which contains the nozzle axis Ho and is parallel to the valve axis. The plane Sh is perpendicular to... Figure 7 , Figure 8 The planes are orthogonal to the paper surface. As a second requirement, the specific flat nozzle 131 has planar portions 157 and 158 on its inner wall that are opposed to each other across the long axis Ha. Figure 8 In the diagram, the area enclosed by two straight lines represents the planar portion. Additionally, in each figure, only a portion of the nozzles are shown with straight lines representing the boundaries of the planar portion.

[0091] A liquid film LF is illustrated on the inner wall of the planar portion 157 on the side separated from the major axis Ha, but not on the inner wall of the planar portion 158 on the side separated from the major axis Ha. (See reference...) Figure 9 As will be described later, the liquid film LF is the fuel injected along the inner wall. Figure 7In the nozzle configuration, for nozzle 1 511 and nozzles 4 and 5 514 and 515, which are inclined in a radial direction outward from the valve shaft Z, the inner wall on the valve shaft Z side is "the inner wall on the side along which the fuel is injected". Furthermore, for nozzles 2 and 3 512 and 513, which are inclined in a direction away from the reference plane Sy, the inner wall on the reference plane Sy side is "the inner wall on the side along which the fuel is injected".

[0092] The third requirement for a specific flat nozzle is that "the radius of curvature ratio ρ is in the range of 40% to 100%". Semantically, "40% to 100%" is interpreted as "more than 40% and less than 100%". Figure 7 , Figure 8 The radius of curvature ratio ρ of the specific flat nozzle 131 represented in the figure is equivalent to 100%. Here, the second radius of curvature R2 used in the calculation of the radius of curvature ratio ρ is defined as the radius of curvature of the end of the outlet opening 15 in the long axis direction of the inner wall on the side along which the fuel is injected relative to the long axis Ha. However, in Figure 7 , Figure 8 In the shape, since the radius of curvature on both sides relative to the major axis Ha is R2, the radius of curvature on either side can be used.

[0093] Reference Figure 9 , Figure 10 The nozzle shape of the specific flat nozzle 131 in the first embodiment will be described. Figure 9 In, it is shown that in Figure 4 The diagram shows the state of the fuel film LF along the inner wall of the nozzle 13 during injection in the axial section of the nozzle shaft Ho. The depth direction of the paper corresponds to the major axis direction. In this example, the fuel flows along the inner wall closer to the valve shaft Z, while the fuel does not flow along the inner wall farther from the valve shaft Z. Hereinafter, the plane portion of the inner wall along the side of the major axis will be designated "157", and the plane portion of the inner wall not along the side of the fuel will be designated "158". Furthermore, regarding the "side along which the fuel does not flow during injection", for the sake of clarity, it will be designated "the opposite side of the side along which the fuel flows during injection".

[0094] Figure 10 yes Figure 9 The projected view in the X direction, i.e., the direction of the nozzle axis Ho. (Compared to...) Figure 9 The section orthogonal to the nozzle axis Ho, represented by the dashed line, is in... Figure 10The inlet opening 14 and outlet opening 15 are referred to as such. The inlet opening 14 is a perfect circle with a radius of the first radius of curvature R1. The outlet opening 15 has a semi-circular end along its major axis with a radius of the second radius of curvature R2. In the first embodiment, during injection, the inner wall shape of the fuel on the side along its major axis Ha (i.e., the side of the planar portion 157) and the inner wall shape on the opposite side (i.e., the side of the planar portion 158) are symmetrical.

[0095] Furthermore, since the expansion angle of the inner wall in the cross-section along the short axis Hb is 0°, the length of the short axis Hb of the outlet opening 15 is equal to the diameter of the inlet opening 14 (=2×R1). Therefore, in the specific flat nozzle 131 of the first embodiment, "R1=R2". By minimizing the outlet opening area on the opposite side of the side along which the fuel is injected relative to the long axis Ha, according to the understanding of Patent Document 1, it is difficult for incomplete combustion products (deposits) to accumulate on the inner wall.

[0096] Next, refer to Figure 11 , Figure 12 The concept of "liquid film homogeneity" will be explained. Figure 11 The diagram schematically illustrates the fluctuation (deviation) in the thickness of the liquid film LF along the inner wall of a specific flat nozzle 131, depending on its position along the long axis. Let the average liquid film thickness be Lave, and let ΔL be the difference between the liquid film thickness at each location and the average liquid film thickness Lave. For example, the value obtained by dividing the standard deviation σ of the liquid film thickness by the average liquid film thickness Lave (σ / Lave) is defined as "liquid film homogeneity." The smaller the value of liquid film homogeneity, the higher the spray dispersion, and the greater the reduction in wall wet.

[0097] exist Figure 12 The table shows the analytical results regarding the relationship between the radius of curvature ratio ρ of a flat nozzle and the homogeneity of the liquid film. In the region where the radius of curvature ratio ρ ranges from 0% to approximately 70%, the value of liquid film homogeneity decreases as the radius of curvature ratio ρ increases. In the region where the radius of curvature ratio ρ ranges from approximately 70% to 100%, the value of liquid film homogeneity increases as the radius of curvature ratio ρ increases. That is, at a radius of curvature ratio ρ of approximately 70%, the value of liquid film homogeneity becomes minimal.

[0098] When setting the target value tgt1 of the liquid film homogeneity as indicated by the single-dot dash line, when the curvature radius ratio ρ is 40% or more and 100% or less, the value of the liquid film homogeneity becomes below the target value tgt1. This is the basis for stipulating the "curvature radius ratio ρ in the range of 40% to 100%" as the third requirement for a specific flat nozzle. Since "R1 = R2" for the specific flat nozzle 131 of the first embodiment, the curvature radius ratio ρ is 100%, and thus it is included in this range. Thereby, the fuel injection valve 701 of the first embodiment can achieve highly dispersed and highly homogeneous spraying. Thereby, the fuel after attachment can be evaporated quickly, achieving a reduction in wall wetting.

[0099] In addition, when setting the target value tgt2 of the liquid film homogeneity as indicated by the double-dot dash line, when the curvature radius ratio ρ is 50% or more and 90% or less, the value of the liquid film homogeneity becomes below the target value tgt2. Therefore, in order to achieve better liquid film homogeneity, it is preferable that the curvature radius ratio ρ of the specific flat nozzle is in the range of 50% to 90%. In this case, since it is set as "R1 > R2", it is preferable to adopt the structures such as the second to fifth embodiments described below.

[0100] [Deformation of nozzle shape]

[0101] Next, referring to Figures 13-17 , as the second to fifth embodiments, deformations of the shape of the specific flat nozzle different from the first embodiment will be described. The shapes of the specific flat nozzles 132 to 135 of each embodiment are represented by the projection views in the direction of the nozzle axis Ho, which correspond to those of the first embodiment. In each figure, the liquid film LF of the fuel along the inner wall during injection is illustrated in the same way as Figure 10 . Figure 10

[0102] In the second to fourth embodiments, the inlet opening 14 is a perfect circle, and its radius is the first curvature radius R1. In addition, in the second to fifth embodiments, commonly, the curvature radius at the long-axis end of the outlet opening 15 in the inner wall on the side where the fuel is along the long axis Ha during injection (i.e., the plane portion 157 side) is the second curvature radius R2. In the second and third embodiments, the length of the short axis Hb of the outlet opening 15 is equal to the diameter of the inlet opening 14 ( = 2×R1).

[0103] (Second embodiment)

[0104] Figure 13 For the specific flat nozzle 132 of the second embodiment shown, the second curvature radius R2 at the long-axis end of the outlet opening 15 is set smaller than the first curvature radius R1 of the inlet opening 14 on the inner walls on both sides with respect to the long axis Ha. That is, the relationship of "R2 < R1" holds.

[0105] A straight portion 159 is formed on the inner wall in the minor axis direction of the outlet opening 15. That is, the outlet opening 15 is formed in a substantially rectangular shape with arcs at the four corners having a second curvature radius R2. In the second embodiment, the relationship of "R2 < R1" can be achieved with a simple shape according to the target value of the curvature radius ratio ρ.

[0106] (Third Embodiment)

[0107] Figure 14 In the specific flat nozzle hole 133 of the third embodiment shown, in the inner wall on the side (i.e., the flat portion 157 side) along which the fuel travels with respect to the long axis Ha during injection, the second curvature radius R2 at the long axis direction end of the outlet opening 15 is set smaller than the first curvature radius R1 of the inlet opening 14. Further, in the inner wall on the opposite side (i.e., the flat portion 158 side) to the side along which the fuel travels with respect to the long axis Ha during injection, a third curvature radius R3, which is the curvature radius at the long axis direction end of the outlet opening 15, is set larger than the first curvature radius R1 of the inlet opening 14. That is, the relationship of "R2 < R1 < R3" holds.

[0108] In Figure 14 the example is illustrated as "R2 + R3 = 2 × R1", and no straight portion is provided on the inner wall in the minor axis direction. In the case of "R2 + R3 < 2 × R1", a straight portion can also be provided on the inner wall in the minor axis direction. In the third embodiment, it is possible to reduce the outlet opening area on the opposite side to the side along which the fuel travels with respect to the long axis Ha during injection. Thus, based on the recognition in Patent Document 1, it is difficult for incomplete combustion products (deposits) to accumulate on the inner wall.

[0109] (Fourth Embodiment)

[0110] Figure 15 In the specific flat nozzle hole 134 of the fourth embodiment shown, the length (2 × R2) of the minor axis Hb is set smaller than the diameter (2 × R1) of the inlet opening 14 with respect to the specific flat nozzle hole 131 of the first embodiment. That is, the relationship of "R2 < R1" holds. Here, on the side (i.e., the flat portion 157 side) along which the fuel travels with respect to the long axis Ha during injection, the positions of the inner walls of the inlet opening 14 and the outlet opening 15 with respect to the nozzle hole axis Ho are the same.

[0111] On the other hand, on the opposite side (i.e., the flat portion 158 side) to the side along which the fuel travels with respect to the long axis Ha during injection, a part of the inner wall is formed such that it gets closer to the nozzle hole axis Ho as it goes from the inlet opening 14 towards the outlet opening 15. That is, a surface is formed with an inclination opposite to that of a normal conical nozzle hole. In such a structure, the relationship of "R2 < R1" can also be achieved.

[0112] (Fifth Embodiment)

[0113] Figure 16 For the specific flat injection hole 135 of the fifth embodiment shown, the inlet opening 14 is not a perfect circle as compared with the specific flat injection hole 131 of the first embodiment. When injecting fuel, on the side along the major axis Ha (i.e., the plane portion 157 side), the first curvature radius R1 of the inlet opening 14 is set to be larger than the second curvature radius R2 of the end portion in the major axis direction of the outlet opening 15. On the other hand, on the side opposite to the side along the major axis Ha of the fuel during injection (i.e., the plane portion 158 side), the fourth curvature radius R4 of the inlet opening 14 is set to be smaller than the second curvature radius R2 of the end portion in the major axis direction of the outlet opening 15. That is, the relationship of "R4 < R2 < R1" holds.

[0114] In this way, the inlet opening 14 may not be a perfect circle. For example, by performing additional processing on the product processed in the shape of the specific flat injection hole 131 of the first embodiment in the shape of the specific flat injection hole 135 of the fifth embodiment, it is possible to correct in the direction of reducing the curvature radius ratio ρ.

[0115] [Variations in the number of injection holes and the configuration of injection holes]

[0116] Next, referring to Figures 17-23 , as the sixth to eleventh embodiments, variations in which the number or configuration of multiple injection holes is different from that of the first embodiment will be described. Among them, the sixth to ninth embodiments are the same as the first embodiment and are specifications for the side-mounted engine 801 shown in Figure 2 , Figure 3 . The tenth and eleventh embodiments are specifications for the mid-mounted engine 802 shown in Figure 21 .

[0117] The injection hole configurations of the sixth to eleventh embodiments are represented by the projection views in the valve shaft Z direction corresponding to Figure 7 of the first embodiment. In common among the embodiments, the center of the inlet opening 14 is arranged on the concentric circle centered on the valve shaft Z. In addition, as described above, in the projection in the valve shaft Z direction, the farther the center of the inlet opening 14 is from the center of the outlet opening 15, the larger the injection hole angle γ referred to in Figure 4 , Figure 10 .

[0118] In the embodiments other than the ninth embodiment, all the injection holes form specific flat injection holes. That is, the major axis Ha is orthogonal to the plane Sh that includes the injection hole axis Ho and is parallel to the valve shaft, and the inner wall has plane portions that face each other across the major axis Ha. As Figure 8As shown, since the plane Sh is represented by the same line as the nozzle axis Ho, the description of "Sh" in the figure is omitted. The radius of curvature ratio ρ is in the range of 40% to 100%. In addition, in the 9th embodiment, a portion of the nozzles constitutes a specific flat nozzle.

[0119] Furthermore, in embodiments 6 to 11, the description of "utilizing the wall-attachment effect between two sprays to avoid spray interference caused by negative pressure generated in the closed space formed by the three adjacent sprays" mentioned above in embodiment 1 is also cited.

[0120] (Sixth Embodiment)

[0121] Figure 17 The fuel injection valve 706 of the sixth embodiment shown is similar to the fuel injection valve 701 of the first embodiment, with five specific flat nozzles 521-525 arranged around the valve shaft Z. Compared with the first embodiment, the diameter of the inlet opening 14 is larger in the sixth embodiment. Furthermore, the ratio of the length of the major axis Ha to the length of the minor axis Hb of nozzles 2-5 is greater than that of nozzle 1 521. That is, nozzles 2-5 522-525 are formed as flat nozzles with a greater degree of flatness. In addition, the nozzle angle γ of nozzles 2 and 3 522 and 523 is the largest.

[0122] In this way, even with the same side-mounted 5-hole specification, the size and shape of each nozzle, as well as the detailed configuration, can be appropriately designed. Basically, regardless of the specification of the specific flat nozzle used, a highly dispersed and homogeneous spray can be achieved.

[0123] (Seventh Embodiment)

[0124] Figure 18 The fuel injection valve 707 of the seventh embodiment shown has six specific flat injection holes 611-616 arranged around the valve shaft Z. Injection hole 1 611 and injection hole 616 are arranged on the reference plane Sy, and injection holes 2 and 3 612, 613 and injection holes 4 and 5 614, 615 are arranged symmetrically with respect to the reference plane Sy. Injection holes 2 and 3 612, 613 and injection holes 4 and 5 614, 615 are arranged such that their major axis Ha extends from the side of injection hole 616 toward the side of injection hole 1 611 and away from the reference plane Sy.

[0125] If we focus on the nozzle angle γ, nozzle 1 (611) has the smallest nozzle angle γ, followed by nozzles 2 and 3 (612 and 613) and nozzle 6 (616) with relatively small nozzle angle γ. Furthermore, nozzles 4 and 5 (614 and 615) have the largest nozzle angle γ.

[0126] For nozzles 611 (No. 1), 614 (No. 4), 615 (No. 5), and 616 (No. 6), whose nozzle shaft Ho is inclined in a radially outward direction toward the valve shaft Z, the inner wall on the valve shaft Z side is defined as "the inner wall on the side along which the fuel is injected". Furthermore, for nozzles 612 (No. 2) and 613 (No. 3), whose nozzle shaft Ho is inclined in a direction away from the reference plane Sy, the inner wall on the reference plane Sy side is defined as "the inner wall on the side along which the fuel is injected".

[0127] In the seventh embodiment, where all six nozzles form a specific flat nozzle, highly dispersed and homogeneous spray can also be achieved. Furthermore, in the six-hole configuration, besides nozzles 1, 2, and 3 (611, 612, 613), nozzles 2, 4, and 6 (612, 614, 616) and nozzles 3, 5, and 6 (613, 615, 616) also generate negative pressure in the closed space formed between adjacent three spray holes, contributing to spray interference. Therefore, the avoidance of spray interference achieved through the wall-attachment effect between two spray holes becomes more effective.

[0128] (Eighth Embodiment)

[0129] Figure 19 The fuel injection valve 708 of the eighth embodiment shown is a variation of the fuel injection valve 707 of the seventh embodiment in terms of nozzle configuration, except that the configuration of nozzle 621 is different from that of the fuel injection valve 707. That is, the nozzle axis Ho of nozzle 621 is inclined radially inward from the inlet opening 14 toward the outlet opening 15 toward the valve axis Z side, that is, in relation to the valve axis Z. In this structure, regarding nozzle 621, unlike the other nozzles 612-616, the inner wall on the side opposite to the valve axis Z, that is, the inner wall on the radially outer side relative to the valve axis Z, is the "inner wall along which the fuel is injected".

[0130] Thus, the "inner wall along the side where the fuel is injected" is not always the inner wall on the Z side of the valve shaft. Regarding nozzle 621, in the projection of the valve shaft in the Z direction, viewed from the outlet opening 15, the inner wall on the side of the inlet opening 14 is the "inner wall along the side where the fuel is injected". With this structure, highly dispersed and highly homogeneous spray can also be achieved.

[0131] (9th embodiment)

[0132] Figure 20The fuel injection valve 709 of the ninth embodiment shown is another variation of the fuel injection valve 707 of the seventh embodiment regarding the nozzle configuration. In the fuel injection valve 709, only nozzles 4 and 5, 614 and 615, are specific flat nozzles common to the fuel injection valve 707; the other four nozzles 601, 602, 603, and 606 are circular nozzles. No. 4 and 5 nozzles 614 and 615 correspond to the pair of nozzles with the largest nozzle angle γ among the six nozzles. It is conceivable that the high dispersion and high homogeneity of the spray achieved by adopting the shape of the specific flat nozzles is maximized.

[0133] Thus, it is not necessary for all the nozzles to constitute a specific flat nozzle; rather, a portion of the nozzles may constitute a specific flat nozzle, while the remaining nozzles are either circular nozzles or flat nozzles that are not specific flat nozzles. In this case, among the multiple nozzles arranged symmetrically with respect to the reference plane Sy, it is preferable that at least the pair of nozzles with the largest nozzle angle γ constitutes a specific flat nozzle. For example, in the fuel injection valve 701 of the first embodiment with a 5-hole configuration, it is preferable that at least nozzles 4 and 514, 515 constitute a specific flat nozzle.

[0134] (10th and 11th embodiments)

[0135] Next, refer to Figures 21-23 The fuel injection valves of embodiments 10 and 11 will be described. The fuel injection valves of embodiments 10 and 11... Figure 21 The mid-mounted engine 802 shown is mounted in the center of the cylinder head, injecting multiple cone-shaped fuel sprays Fo into the combustion chamber 83. For example, in Japanese Patent Application Publication No. 2018-31275... Figure 11 The engine was revealed to be mid-mounted. Figure 21 The fuel injection valves in the diagram are labeled with "70" as a general term.

[0136] Figure 22 The fuel injection valve 710 of the tenth embodiment shown has five specific flat injection holes 531-535 arranged in a generally radial pattern around the valve shaft Z. Injection hole 531 is located on the reference plane Sy on the side opposite to the spark plug 97, and the other four injection holes 532-535 are arranged symmetrically with respect to the reference plane Sy. The injection hole axis Ho of each injection hole 531-535 is inclined toward the radial direction outward from the valve shaft Z, and the inner wall of the valve shaft Z side is the inner wall of the side along which the fuel is injected.

[0137] Figure 23The fuel injection valve 711 of the 11th embodiment shown has six specific flat nozzles 631-636 arranged symmetrically around the valve shaft Z relative to the reference plane Sy. The nozzle angle γ of nozzles 3 and 4 (633, 634) is larger than that of nozzles 1 and 2 (631, 632), and the nozzle angle γ of nozzles 5 and 6 (635, 636) is set to be relatively large. Therefore, the nozzles 631-636 are not evenly radial, but nozzles 3 and 4 (633, 634) are offset towards the spark plug 97 side relative to the reference orthogonal plane Sx. The nozzle shaft Ho of each nozzle 631-636 is inclined approximately outward from the valve shaft Z, and the inner wall on the valve shaft Z side becomes the "inner wall along the side along which the fuel is injected".

[0138] Thus, by making one or more nozzles specific flat nozzles in the fuel injection valves 710 and 711 mounted on the mid-mounted engine 802, highly dispersed and highly homogeneous spray can also be achieved.

[0139] (Other implementation methods)

[0140] (a) It is also possible that not all of the flat nozzles are specific flat nozzles. That is, it is also possible to include in part "flat nozzles whose major axis Ha is not orthogonal to the plane Sh containing the nozzle axis Ho and parallel to the valve axis Z", or "flat nozzles that do not have a flat portion on the inner wall", or "flat nozzles with a radius of curvature ratio of less than 40%".

[0141] (b) Alternatively, a surface 122 on the side opposite to the nozzle barrel 11 of the nozzle bottom 12 may be formed around the opening of the nozzle orifice 13, for example, in Patent Document 2. Figure 22 The recess is as shown. In this structure, the opening formed on the bottom surface of the recess is considered as the outlet opening 15, and the axis passing through the center of the outlet opening 15 is defined as the nozzle axis Ho. By forming the recess, the length of the nozzle axis can be adjusted to be shorter.

[0142] (c) The structure of the components in the fuel injection valve is not limited to... Figure 1 The structure shown can also be modified to achieve the same function. For example, adjacent components of the same material can be formed separately or as a single piece.

[0143] (d) The fuel injection valve disclosed herein is not limited to direct injection gasoline engines, but can also be applied to diesel engines or intake manifold fuel injection gasoline engines, etc.

[0144] The present disclosure is not limited to such implementation methods and can be implemented in various forms without departing from its spirit.

[0145] This disclosure has been described based on embodiments. However, this disclosure is not limited to these embodiments and structures. This disclosure also includes various modifications and equivalent variations. Furthermore, various combinations and forms, and even combinations and forms that include only one element, or include more or less of it, also fall within the scope and spirit of this disclosure.

Claims

1. A fuel injection valve, comprising: a nozzle, provided centered on a valve shaft, having: a nozzle barrel portion that forms a fuel passage inside; a nozzle bottom portion that closes one end of the nozzle barrel portion; a plurality of spray holes that connect the surface of the nozzle barrel portion side of the nozzle bottom portion and the surface opposite to the nozzle barrel portion, and spray the fuel in the fuel passage; and an annular valve seat that is formed in the surface of the nozzle barrel portion side of the nozzle bottom portion around the spray holes; a needle, arranged to be reciprocally movable along the valve shaft inside the nozzle, closing the spray holes when abutting against the valve seat and opening the spray holes when departing from the valve seat; and a drive portion, capable of moving the needle in the valve-opening direction or the valve-closing direction, the spray holes having: an inlet opening portion, formed in the surface of the nozzle barrel portion side of the nozzle bottom portion; and an outlet opening portion, formed in the surface opposite to the nozzle barrel portion of the nozzle bottom portion, and having an area larger than the area of the inlet opening portion, one or more of the plurality of spray holes are flat spray holes having a long axis and a short axis for the outlet opening portion, and the flat spray holes further include one or more specific flat spray holes; the specific flat spray holes, the long axis of which is orthogonal to a plane that includes the spray hole axis connecting the center of the inlet opening portion and the center of the outlet opening portion and is parallel to the valve shaft; having plane portions opposed to each other across the long axis on the inner wall; in the inner wall on the side where the fuel runs along with respect to the long axis during injection, if the curvature radius of the end portion in the long axis direction of the inlet opening portion is defined as the first curvature radius, and the curvature radius of the end portion in the long axis direction of the outlet opening portion is defined as the second curvature radius, and the ratio of the second curvature radius to the first curvature radius is defined as the curvature radius ratio, then the curvature radius ratio is in the range of 40% to 100%, the plurality of spray holes are symmetrically arranged with respect to a reference plane including the valve shaft, at least a pair of spray holes with the largest spray hole angle constitute the specific flat spray holes, and the spray hole angle is the angle of the spray hole axis with respect to a hypothetical axis parallel to the valve shaft, the specific flat spray holes, ​ ​ ​ ​ ​ ​ ​ ​ ​

Images