JP7113943B1 - fuel injector - Google Patents

Abstract

A fuel injection valve capable of adjusting the spray angle of a fuel spray while improving the atomization performance of the fuel spray is provided. A center of an injection hole (13b) is offset from a center axis of an introduction part (13b) in a direction in which a first side wall (13b1) exists, and is aligned with a center of a swirl chamber (13c). The swirling chamber (13c) has a curved wall portion (13c1) formed by a part of a virtual arc, and the curved wall portion (13c1) is connected to a linearly extending facing wall portion (13c2). The shortest distance between the central axis of the introduction part (13b) and the center of the injection hole (14) is T, the center of the injection hole (14) and the facing wall The facing wall portion (13c2) is arranged within a range that satisfies [0.8T≤G≤1.2T], where G is the shortest distance between the wall portion (13c2) fuel injection valve. [Selection drawing] Fig. 3

Description

The present application relates to fuel injection valves.

In recent years, as exhaust gas regulations for automobile internal combustion engines have been tightened, the fuel spray injected from the fuel injection valve has been designed to suppress the excessive spread of the spray angle in consideration of the adhesion to the intake pipe wall surface. However, there is a demand for sufficiently atomized fuel spray, and various studies have been made on methods utilizing swirl flow as one of atomization techniques.

For example, in Patent Literature 1, a valve seat having a valve seat opening through which fuel passes from the upstream side, a valve body for opening and closing the valve seat opening, and a fuel swirling flow forming valve provided downstream of the valve seat are disclosed. and a radial depression having a branching portion, an introduction portion, a cylindrical portion, and a turning portion is processed on the upstream side of the injection hole plate, and an injection hole portion is processed on the downstream side of the cylindrical portion. , and a fuel injection valve is disclosed in which further atomization of the spray is achieved by defining the dimensions of the flow passage including the swirling portion.

In Patent Document 1, the end surface of the turning portion of the nozzle hole plate is inclined at an angle θ with respect to the central axis of the introduction portion, and by setting the angle θ to be in the range of 0° or more and 45° or less, the cylindrical When the flow A flowing directly from the introduction portion and the flow B flowing into the cylindrical portion via the swirling portion are opposed to each other, and the width of the introducing portion is W1 and the width of the swirling portion is W2. , [0.3≤W2/W1≤0.7], the strengths of the flow A and the flow B are substantially equal. As a result, the swirl flow becomes homogeneous and the film thickness of the fuel liquid formed on the inner wall of the injection hole becomes uniform, so that the degree of atomization is improved.

On the other hand, in the above-described conventional fuel injection valve disclosed in Patent Document 1, in which the swirling flow thins the fuel and splits the liquid film to atomize it, the swirling force of the fuel is improved, which promotes the spread of the liquid film. It promotes atomization, but at the same time, the spray angle is greatly enlarged.

WO2017/060945

In the conventional fuel injection valve disclosed in Patent Document 1, as described above, the improvement in the turning force promotes the spread of the liquid film and promotes atomization, but at the same time, the problem is that the spray angle is greatly enlarged. was there.

There are various possible methods for adjusting the spray angle to obtain the desired spray angle. is turned into a swirl flow in the swirl chamber and injected from the nozzle hole. At this time, the fuel sufficiently rectified in the introduction portion becomes a uniform swirl flow in the swirl chamber, and becomes a fuel spray that is further thinned and atomized.

Therefore, the length of the introduction portion, which determines the degree of rectification, is an important parameter from the viewpoint of suppressing the spread of the spray by adjusting the turning force. By adjusting the length L of the first side wall portion of the fuel flow A and the length M of the second side wall portion of the flow B, the degree of rectification of each flow, that is, the swirling force of the flow A or the flow B can be adjusted.

Here, in the conventional fuel injection valve disclosed in Patent Document 1, the introduction portion is connected to the cylindrical portion and the swirl portion, and the swirl portion is formed so as to surround the cylindrical portion. The change in length means that the lengths of the first side wall portion and the second side wall portion are changed at the same time, and the swirling force of both the flow A and the flow B is changed, so the atomization of the fuel, the injection flow rate, etc. influence becomes greater. In addition, changes in the width of the introduction section and the amount of offset of the injection hole are accompanied by changes in the diameter of the swirl chamber, resulting in large changes in the swirl force, and not only in the atomization performance, but also in the injection flow rate. , the number of man-hours for designing to obtain the target spray angle while maintaining the required flow rate becomes enormous.

The present application discloses a technique for solving the above-described problems, and an object thereof is to provide a fuel injection valve having a desired spray angle of the fuel spray while improving the atomization performance of the fuel spray. and

The fuel injection valve disclosed in the present application is
a valve seat having a valve seat opening through which fuel flows out; a valve body that opens and closes the valve seat opening; and an injection hole plate having a plurality of injection hole portions for injecting into the valve seat opening portion by moving the valve body in the axial direction of the valve seat based on an operation signal from an external control device. A fuel injection valve that opens and closes to control injection of the fuel from the injection hole,
The injection hole plate is
a plurality of swirl chambers arranged radially outside the valve seat opening on the end surface on the upstream side of the flow of the fuel;
a central portion connected to the valve seat opening;
a plurality of introduction portions for guiding the fuel from the central portion to each of the swirl chambers;
with
The introduction portion has a first side wall portion and a second side wall portion facing each other across a central axis of the introduction portion,
The center of the nozzle hole is
provided so as to be offset in the direction in which the first side wall portion exists with respect to the central axis of the introduction portion and coincide with the center of the swirl chamber;
The swirl chamber has a curved wall portion formed by a part of a virtual arc,
The curved wall portion is connected to the first side wall portion via a linearly extending facing wall portion,
When the shortest distance between the central axis of the introduction portion and the center of the nozzle hole is T, and the shortest distance between the center of the nozzle hole and the facing wall is G,
The facing wall portion is arranged within a range that satisfies [0.8T≦G≦1.2T],
It is designed to

According to the fuel injection valve disclosed in the present application, it is possible to obtain a fuel injection valve having a desired spray angle of the fuel spray while improving the atomization performance of the fuel spray.

1 is a cross-sectional view showing a fuel injection valve according to Embodiment 1; FIG. 4 is an enlarged cross-sectional view showing the tip portion of the valve body, the valve seat, and the injection hole plate in the fuel injection valve according to Embodiment 1; FIG. FIG. 2B is a plan view of the nozzle hole plate in the fuel injection valve according to Embodiment 1 as viewed from the direction of arrow Z in FIG. 2A; FIG. 4 is an explanatory diagram showing the flow of fuel in an injection hole plate in the fuel injection valve according to Embodiment 1; FIG. 4 is an explanatory diagram showing the flow of fuel in an injection hole plate in the fuel injection valve according to Embodiment 1; FIG. 9 is an explanatory diagram showing the flow of fuel in an injection hole plate in a fuel injection valve according to Embodiment 2; FIG. 2 is an explanatory diagram for explaining the fuel injection valve according to Embodiment 1 based on experimental results; FIG. 2 is an explanatory diagram for explaining the fuel injection valve according to Embodiment 1 based on experimental results; FIG. 2 is an explanatory diagram for explaining the fuel injection valve according to Embodiment 1 based on experimental results;

Embodiment 1.
1 is a cross-sectional view showing a fuel injection valve according to Embodiment 1, and FIG. 2A is an enlarged cross-sectional view showing a tip portion of a valve element, a valve seat, and an injection hole plate in the fuel injection valve according to Embodiment 1; 2B is a plan view of the injection hole plate in the fuel injection valve according to Embodiment 1, viewed in the direction of arrow Z in FIG. 2A. 1, 2A, and 2B, the fuel injection valve 1 includes a solenoid device 4, a housing 5 as a yoke portion of a magnetic circuit, a core 6 as a fixed iron core portion of the magnetic circuit, a coil 7, and a magnetic circuit. and an armature 8 as a movable iron core portion, and a valve device 9. The valve device 9 is composed of a valve body 10 , a valve holder 11 and a valve seat 12 .

The valve holder 11 is welded and fixed to the core 6 after being press-fitted into the outer diameter portion of the core 6 . The armature 8 is welded and fixed to the valve body 10 after being press-fitted into the valve body 10 . On the downstream side of the valve seat 12, the nozzle hole plate 13 is welded to the valve seat 12 at the welding part 50, and the valve seat 12 and the nozzle hole plate 13 are attached to the inside of the valve holder 11 as an integral structure. there is The injection hole plate 13 is provided with a plurality of injection hole portions 14 penetrating in the plate thickness direction.

The valve element 10 is always biased away from the end surface of the core 6 toward the valve seat 12 by a compression spring 16 . The sliding portion 8a, which is the outer peripheral surface portion of the armature 8, is in contact with the inner peripheral surface portion of the guide portion 11a provided in the valve holder 11 so as to be slidable in the axial direction of the valve body 10, and is fixed to the armature 8. The valve body 10 can move axially together with the armature 8 .

The nozzle hole plate 13 includes a central portion 13a communicating with the valve seat opening 12d of the valve seat 12, four groove-shaped introduction portions 13b radially extending from the central portion 13a at angular intervals of 90 degrees, Four swirl chambers 13c coupled to the ends of the respective introduction portions 13b, and four injection hole portions 14 provided in the respective swirl chambers 13c and penetrating the injection hole plate 13 are provided. The bottom surface of the central portion 13a, the bottom surface of each introduction portion 13b, and the bottom surface of each swirl chamber 13c are configured to be aligned on the same plane. Each swirling chamber 13c communicates with each other via the introduction portion 13b and the central portion 13a.

Next, operation of the fuel injection valve 1 will be described. When an operation signal is sent from the control device of the internal combustion engine to the drive circuit of the fuel injection valve 1, current is applied to the coil 7 of the fuel injection valve 1, which is composed of an armature 8, a core 6, a housing 5 and a valve holder 11. A magnetic flux is generated in the magnetic circuit, the armature 8 is attracted toward the core 6 and moves, and the upper surface portion 8b of the armature 8 contacts the lower surface portion of the core 6 . When the valve body 10, which is integrated with the armature 8, separates from the valve seat portion 12a and a gap is formed between the valve body 10 and the valve seat portion 12a, the fuel flows into the tip portion of the valve body 10. From the chamfered portion 15 a of the welded ball 15 , it flows through the gap between the valve seat portion 12 a and the valve body 10 and into the central portion 13 a of the injection hole plate 13 from the valve seat opening 12 d of the valve seat 12 .

The fuel that has flowed into the central portion 13a of the injection hole plate 13 from the valve seat opening 12d of the valve seat 12 flows into the respective swirl chambers 13c through the respective introduction portions 13b. The fuel that has flowed into each swirl chamber 13c flows into each injection hole portion 14 while generating a swirling flow. A liquid film is formed. A thin liquid film formed along the inner walls of the injection holes is injected into the intake port of the internal combustion engine from each injection hole 14 in a hollow conical shape, promoting atomization of the fuel.

Next, when an operation stop signal is sent from the control device of the internal combustion engine to the drive circuit of the fuel injection valve 1, the current supply to the coil 7 is stopped and the magnetic flux in the magnetic circuit is reduced. As a result, the valve element 10 is moved toward the valve seat 12 by the pressing force of the compression spring 16, and the surface of the ball 15 is seated on the valve seat portion 12a of the valve seat 12, thereby moving the ball 15 and the valve seat. The gap between the portion 12a and the portion 12a is closed, and the fuel injection ends.

3 and 4 are explanatory diagrams showing the flow of fuel in the injection hole plate in the fuel injection valve according to Embodiment 1, and show the central portion 13a and the introduction portion 13b of the injection hole plate 13 shown in FIG. 2B. , the swirling chamber 13c, and the injection hole portion 14 are shown in an enlarged manner. In the following description, only one introduction portion 13b, one swirling chamber 13c, and one injection hole portion 14 will be explained based on FIG. The same is true for

In FIG. 3, the introduction portion 13b has a first side wall portion 13b1 and a second side wall portion 13b2 facing each other across the central axis X of the introduction portion 13b. The center 14a of the injection hole portion 14 is offset from the central axis X of the introduction portion 13b in the direction in which the first side wall portion 13b1 exists, and is provided so as to coincide with the center of the swirl chamber 13c. The swirl chamber 13c has a curved wall portion 13c1 formed by a portion of an imaginary arc. The curved wall portion 13c1 is connected to the first side wall portion 13b1 of the introduction portion 13b via a straight wall portion 13c2.

Here, when the shortest distance between the central axis X of the introduction portion 13b and the center 14a of the injection hole portion 14 is T, the shortest distance G between the center 14a of the injection hole portion 14 and the facing wall portion 13c2 is , is set so as to satisfy the following formula (1).

0.8T≦G≦1.2T Expression (1)

That is, the facing wall portion 13c2 of the swirl chamber 13c is arranged at a position that satisfies the formula (1).

The shortest distance T between the central axis X of the introduction portion 13b and the center 14a of the injection hole portion 14 indicates the amount of offset of the center 14a of the injection hole portion 14 with respect to the central axis X of the introduction portion 13b.

As described above, the first side wall portion 13b1 and the facing wall portion 13c2 are directly connected to each other, and the facing wall portion 13c2 is installed at a position that satisfies the above formula (1). The cross-sectional area of the flow path when the flow B in which the fuel flows into the injection hole portion 14 reaches the vicinity of the injection hole portion 14 via the swirl chamber 13c, and the fuel directly flows into the injection hole portion 14 from the introduction portion 13b. The difference between the cross-sectional area of the flow path when the flow A reaches the vicinity of the injection hole portion 14 is within a certain range.

As a result, the length L of the first side wall portion 13b1, which greatly affects the degree of rectification of the flow A, can be freely set while suppressing the balance between the strengths of the swirling forces of the flow A and the flow B from significantly collapsing. This makes it possible to adjust the strength of the swirling force of the flow A that directly flows into the injection hole portion 14 . Also, the angle of the facing wall portion 13c2 with respect to the central axis X of the introduction portion 13b can be adjusted, and the direction of the flow B flowing into the injection hole portion 14 can be adjusted.

Therefore, the diameter of the swirl chamber 13c, the shortest distance T between the central axis X of the introduction portion 13b and the center 14a of the injection hole portion 14 as the injection hole offset amount, the length M of the second side wall portion 13b2, Without changing the parameters such as, the influence on the fuel flow rate, atomization performance, etc. is minimized, and the balance of the strength of the swirling force between the flow A and the flow B facing each other in the injection hole portion 14 collapses significantly. It is possible to adjust the strength of the swirling force of the flow A and the direction in which the flow B flows into the injection hole portion 14 while maintaining the flow within a range where no flow is possible. That is, the fuel spray angle can be adjusted, and the number of man-hours for adjusting the fuel spray angle can be reduced compared to the conventional fuel injection valve.

A cavity surrounded by the tip of the ball 15 in the valve body 10, the valve seat 12, and the nozzle hole plate 13 constitutes a fuel cavity. It is a factor that is greatly affected by the dynamic flow rate as a change in the fuel flow rate when the atmosphere of the fuel, etc., changes. That is, for example, when injecting fuel into a negative pressure atmosphere, after the fuel injection valve 1 is completely closed, part of the fuel present inside the fuel cavity is sucked into the intake pipe of the engine from the injection hole portion 14 by the negative pressure. Therefore, the change in the flow rate of fuel becomes large. Since the flow rate of the fuel sucked into the engine intake pipe from the inside of the fuel cavity is small, fuel having a large particle size and poor quality is injected into the engine intake pipe immediately after the fuel injection valve 1 is closed. end up

Therefore, when considering the shape of the valve seat 12 and the injection hole plate 13, it is one of the important factors for improving the characteristics of the fuel injection valve 1 to consider the volume of the fuel cavity. In view of this point, the connecting portion b between the curved wall portion 13c1 and the facing wall portion 13c2 of the swirl chamber 13c may be a curved surface Rb (not shown). By forming the connection portion b into the curved surface Rb, the volume of the swirl chamber 13c formed by the curved wall portion 13c1 and the facing wall portion 13c2 is reduced, promoting the atomization of the fuel spray, and reducing the temperature, atmosphere, etc. described above. The flow rate change due to the change in is suppressed.

Further, by forming the connection portion b as the curved surface Rb, the flow B that has passed through the swirl chamber 13c smoothly turns toward the facing wall portion 13c2 by the curved surface Rb when reaching the facing wall portion 13c2. , the pressure loss of the stream B is reduced and the atomization performance is improved. Further, by forming the connecting portion b into the curved surface Rb, the workability of the swirl chamber 13c in the nozzle hole plate 13 is improved. , and the central portion 13a of the injection hole plate 13 by press working, the durability of the mold can be improved.

In addition to forming the connecting portion b into the curved surface Rb, the connecting portion between the facing wall portion 13c2 of the swirl chamber 13c and the first side wall portion 13b1 of the introduction portion 13b may be formed into a curved surface. In this case, the workability of the swirl chamber 13c and the introduction portion 13b is improved, and the durability of the metal mold for the press working described above can be further improved.

FIG. 6 is an explanatory diagram for explaining the fuel injection valve according to Embodiment 1 based on experimental results, in which the vertical axis indicates particle size and the horizontal axis indicates G/T. Here, G/T is the shortest distance T between the central axis X of the introduction portion 13b and the center of the injection hole portion 14, the shortest distance G between the center of the injection hole portion 14 and the facing wall portion 13c2, indicates the percentage of As is clear from FIG. 6, the shortest distance T between the central axis X of the introduction portion 13b and the center of the injection hole portion 14 and the shortest distance G between the center of the injection hole portion 14 and the facing wall portion 13c2 are , in the range that satisfies the relationship of [0.8T≤G≤1.2T] in the above-described formula (1), that is, when G/T is [0.8≤G/T≤1.2] It can be seen that within this range, good fuel injection can be obtained in which the fuel spray particles are relatively small and the change in particle size is small.

Furthermore, as shown in FIG. 4, when the shortest distance between the central axis X of the introduction portion 13b and the first side wall portion 13b1 is w, and the diameter of the injection hole is φDf, the central axis X of the introduction portion 13b and When the shortest distance T of the center 14a of the injection hole portion 14 is arranged in a range that satisfies the following formula (2), that is, a virtual extension line extending the first side wall portion 13b1 in the direction of the injection hole portion 14 When the nozzle holes 14 are arranged at the intersecting positions, the flow A directly flowing into the nozzle holes 14 flows out directly from the nozzle holes 14 without swirling while suppressing excessive spread of the spray. The offset amount of the injection hole portion 14 is set within a range in which the components are suppressed and the atomization performance is maintained.

w<T≦w+φDf/2 Expression (2)

Here, since the degree of rectification of each of the flow A and the flow B is greatly affected by the length L of the first side wall portion 13b1 and the length M of the second side wall portion 13b2, the length L and the length M By setting the value of to a value that satisfies the following formula (3), the difference in the degree of rectification between the flow A and the flow B, that is, the balance of the swirl strength of each of the flows A and B significantly changes. is suppressed.

0.1M≦L Expression (3)

FIG. 7 is an explanatory diagram for explaining the fuel injection valve according to Embodiment 1 based on experimental results, in which the vertical axis is the particle size, and the horizontal axis is the length L of the first side wall portion 13b1 and the second side wall portion 13b1. The length M of the side wall portion 13b2 and the ratio L/M are shown. As is clear from FIG. 7, the relationship between the length L of the first side wall portion 13b1 and the length M of the second side wall portion 13b2 is [0.1≦L/M], that is, [0.1M≦L]. Within the range that satisfies the relationship, significant changes in the balance of the swirl strength of each of the flows A and B are suppressed, and the particle size of the fuel spray becomes a favorable value.

Also, the shortest distance T between the central axis X of the introduction portion 13b and the center of the injection hole portion 14, that is, T as an offset amount of the center 14a of the injection hole portion 14 with respect to the central axis X of the introduction portion 13b, and the injection hole portion 14 and the ratio G/T of the shortest distance G between the center 14a of 14 and the facing wall portion 13c2 is in the range [0.8≦G/T≦1.2] as described above, and the first The relationship between the length L of the side wall portion 13b1 and the length M of the second side wall portion 13b2 is set within a range that satisfies [0.1≦L/M], that is, [0.1M≦L]. It is In this case, if the angle s formed between the first side wall portion 13b1 and the facing wall portion 13c2 becomes small, the difference [M− L] also becomes smaller.

When the shortest distance T between the central axis X of the introduction portion 13b and the center of the injection hole portion 14, that is, the offset amount T of the center 14a of the injection hole portion 14 with respect to the central axis X of the introduction portion 13b, becomes smaller, the injection hole portion In the flow A that directly flows into 14, the component of the flow that directly flows out of nozzle hole 14 without swirling increases. Therefore, the length L of the first side wall portion 13b1 and the length M of the second side wall portion 13b2 are values satisfying the range of [ML≧0.18], that is, [L≦M−0.18]. As a result, significant deterioration in the atomization of the flow A can be suppressed.

FIG. 8 is an explanatory diagram for explaining the fuel injection valve according to Embodiment 1 based on experimental results, in which the vertical axis is the particle size, and the horizontal axis is the length M of the second side wall portion 13b2 and the first first side wall portion 13b2. It shows the difference [ML] between the length L of the side wall portion 13b1. As shown in FIG. 8, the length L of the first side wall portion 13b1 and the length M of the second side wall portion 13b2 are [0.18≦ML], that is, [L≦M−0.18]. When the value satisfies the range, the atomization of the flow A that directly flows into the injection hole portion 14 is suppressed from significantly deteriorating, and the particle size is maintained in a favorable state.

As described above, by setting the length L of the first side wall portion 13b1 and the length M of the second side wall portion 13b2 within the range of [0.1M≤L≤M-0.18], the fuel Significant deterioration of spray fines can be prevented.

式（４）
を満たす形状としている。 Further, as shown in FIG. 4, when considering the virtual circumscribed circle Y of the four swirl chambers 13c in the first embodiment, the radius r of the virtual circumscribed circle Y of the swirl chamber 13c is given by the following equation (4): In order to satisfy the second The length M of the side wall portion 13b2 and the shortest distance w between the central axis X of the introduction portion 13b and the first side wall portion 13b1 are set respectively.

Formula (4)
It has a shape that satisfies

Here, the radius r of the imaginary circumscribed circle Y is the offset amount T of the center 14a of the injection hole portion 14, the shortest distance w between the central axis X of the introduction portion 13b and the first side wall portion 13b1, and the The length M of the two side wall portions 13b2 is a function having parameters, and an increase in the radius r of the imaginary circumscribed circle Y leads to an expansion of the entire lead-in portion 13b, that is, an increase in the machining volume of the lead-in portion 13b. For example, when forming the introduction portion 13b by press molding, when considering a shape that does not protrude to the opposite side of the molding surface, it is difficult to satisfy the required dimensional accuracy of the introduction portion 13b due to a large increase in processing volume. Become. Deterioration of the dimensional accuracy of the introduction portion 13b is a factor that affects the deterioration of variations in the desired flow rate, spray characteristics, etc. Therefore, in order to increase the accuracy of the desired flow rate, spray characteristics, etc., the radius r of the imaginary circumscribed circle Y is set to , [r≤1.315].

As a result, the dimensional accuracy of the introduction part 13b can be maintained satisfactorily by suppressing an excessive increase in the processing volume of the introduction part 13b, and the desired variation level of flow rate, spray characteristics, etc. can be satisfied. . In addition, by suppressing an excessive increase in the volume of the introduction portion 13b, a change in the flow rate when the temperature, atmosphere, etc. change is suppressed. .315].

According to the fuel injection valve according to Embodiment 1 described above, the curved wall portion is connected to the first side wall portion via the facing wall portion extending linearly, and the central axis of the introduction portion and the center of the injection hole portion are aligned. When the shortest distance between the Therefore, when considering a flow A in which the fuel directly flows from the introduction portion to the nozzle hole and a flow B in which the fuel flows into the nozzle hole via the swirl chamber, the flow B passes through the swirl chamber and is injected. By setting the difference between the channel cross-sectional area when reaching the vicinity of the hole and the channel cross-sectional area when the flow A reaches the vicinity of the injection hole within a certain range, the flow A and the flow B It is possible to freely set the length of the first side wall portion, which greatly affects the degree of rectification of the flow A, while suppressing the significant collapse of the balance of the strength of the swirling force. It becomes possible to adjust the turning force strength of.

At the same time, since the angle of the facing wall can be adjusted, the direction in which the flow B flows into the injection hole can be adjusted. Therefore, without changing the parameters such as the diameter of the swirl chamber, the offset amount of the center of the injection hole, and the length of the second side wall, the influence on the flow rate and atomization performance is minimized. It is possible to adjust the swirl strength of the flow A and the direction of the flow B flowing into the nozzle hole while maintaining the balance between the swirl strength of the flow A and the flow B within a range that does not significantly collapse. It is possible to adjust the spray angle, and it is possible to reduce the man-hours for adjusting the spray angle compared to the conventional fuel injection valve.

Further, according to the fuel injection valve according to Embodiment 1, when the shortest distance between the central axis of the introduction portion and the first side wall portion is w, and the diameter of the injection hole portion is φDf, the central axis of the introduction portion and the injection hole The shortest distance T between the center of the nozzle hole and the center of the nozzle is set to a value that satisfies [w<T≤w+φDf/2]. The flow component directly flowing out from the injection hole is suppressed, and the atomization performance is maintained.

Furthermore, according to the fuel injection valve according to Embodiment 1, when the length of the first side wall portion is L and the length of the second side wall portion is M, the first side wall portion and the second side wall portion are separated from each other by [ 0.1M≤L≤M-0.18]. Here, first, for [0.1M≦L], the rectification degree of each of the fuel flow A and the fuel flow B is increased by the length L of the first side wall and the length M of the second side wall. Therefore, by setting the length M and the length L in the range of [0.1M ≤ L], the difference in the degree of rectification between the flows A and B, that is, the strength of the swirling force of each flow Remarkable changes in balance are suppressed.

Next, for [L≦M−0.18], the difference between the length M of the second side wall portion and the length L of the first side wall portion indicated by [ML] is the side wall portion of the facing wall portion. , the shortest distance G between the center of the injection hole and the facing wall, and T as the offset of the center of the injection hole. The difference between the length M of the portion and the length L of the first sidewall portion is also reduced. A decrease in T as an offset amount leads to an increase in the flow component that directly flows out of the nozzle hole without swirling with respect to the flow A that directly flows into the nozzle hole, so [ML≧0.18], that is, By setting the range of [L≦M−0.18], it is possible to suppress significant deterioration of the atomization of the flow A.

From the above, the length L of the first side wall and the length M of the second side wall are in the range of [0.1M ≤ L ≤ M-0.18]. It is desirable from the viewpoint of preventing

を満たす値を有する。仮想外接円の半径ｒは、噴孔部の中心のオフセット量、導入部の幅、第２側壁部の長さＭ、をパラメータに持つ関数となっており、仮想外接円の半径ｒの増加は導入部全体の拡大、すなわち導入部の加工体積の増加につながる。ここで、例えば導入部をプレス成型する際に、成型面と反対側に突出しない形状を検討する場合には、加工体積の大幅な増加により求める導入部の寸法精度を満たすことが困難となる。導入部の寸法精度の悪化は、求める流量、噴霧特性などのばらつきが生じる要素であるため、求める流量、噴霧特性の精度とするために［ｒ≦１．３１５］の範囲内とすることが望ましい。 Further, according to the fuel injection valve according to Embodiment 1, assuming that the length of the second side wall portion is M, and considering the virtual circumscribed circle of the plurality of swirling chambers, the radius r of the virtual circumscribed circle is

has a value that satisfies The radius r of the imaginary circumscribed circle is a function having as parameters the amount of offset of the center of the nozzle hole, the width of the introduction part, and the length M of the second side wall. This leads to enlargement of the entire lead-in portion, that is, increase in processing volume of the lead-in portion. Here, for example, when the introduction portion is press-molded, if a shape that does not protrude to the side opposite to the molding surface is considered, it becomes difficult to satisfy the required dimensional accuracy of the introduction portion due to a large increase in processing volume. Deterioration of the dimensional accuracy of the introduction part is a factor that causes variations in the desired flow rate and spray characteristics, so it is desirable to keep it within the range [r ≤ 1.315] in order to obtain the accuracy of the desired flow rate and spray characteristics. .

That is, by suppressing an excessive increase in the processing volume of the introduction section, it is possible to maintain good dimensional accuracy of the introduction section, and it is possible to obtain values that satisfy the required degree of variation in flow rate and spray characteristics. In addition, by suppressing an excessive increase in the volume of the groove, a change in the flow rate when the temperature, atmosphere, or the like changes is suppressed. From this point of view as well, the range [r≦1.315] is desirable.

Embodiment 2.
Next, a fuel injection valve according to Embodiment 2 will be described. FIG. 5 is an explanatory diagram showing the flow of fuel in the injection hole plate in the fuel injection valve according to Embodiment 2. FIG. As shown in FIG. 5, the facing wall portion 13c2 of the swirling chamber 13c has a radius equal to the shortest distance T between the center axis X of the introduction portion 13b and the center 14a of the injection hole portion 14, and the center of the injection hole portion 14 is the center. It is provided in the vicinity of the tangent line circumscribing the imaginary circle Z coinciding with 14a or at a position overlapping the tangent line. Other configurations are the same as those of the fuel injection valve according to the first embodiment.

According to the fuel injection valve according to Embodiment 2, the first side wall portion 13b1 of the introduction portion 13b and the facing wall portion 13c2 of the swirling chamber 13c are directly connected, and the facing wall portion 13c2 is formed on the tangent line circumscribing the virtual circle Z. By providing it in the vicinity or at a position overlapping with the tangent line, the cross-sectional area of the flow path when the flow B reaches the vicinity of the nozzle hole 14 via the swirl chamber 13c and the flow A reaches the vicinity of the nozzle hole 14 The difference between the cross-sectional area of the flow passage at the time of injection is reduced, the balance between the swirl strength of the flow A and the flow B is further improved, the uniformity of the liquid film thickness in the injection hole portion 14 is improved, and the fuel Atomization of the spray is improved.

Furthermore, in addition to the above, by adjusting the angle of the facing wall portion 13c2 with respect to the central axis X of the introduction portion 13b, it becomes possible to adjust the direction in which the flow B flows into the injection hole portion 14, and at the same time, the first side wall Since the length L of the portion 13b1 can also be adjusted, parameters such as the diameter of the swirl chamber 13c, T as the offset amount of the center 14a of the injection hole portion 14, and the length M of the second side wall portion 13b2 can be adjusted. Without modification, it is possible to balance the strength of the opposing streams A and B at the orifice 14 with minimal impact on fuel flow rate, atomization performance, etc., thus atomizing The angle can be adjusted, and the man-hours for adjusting the spray angle can be reduced compared to the conventional fuel injection valve.

Although this application has described exemplary embodiments, the various features, aspects, and functions described in these embodiments are not limited to application of particular embodiments, but are solely , or in various combinations applicable to the embodiments. Therefore, countless modifications not illustrated are envisioned within the scope of the technology disclosed in the present application. For example, modification, addition or omission of at least one component, extraction of at least one component, and combination with components of other embodiments shall be included. In the present application, the unit of length is [mm], but the unit is omitted in order to avoid complication of notation.

1 fuel injection valve, 4 solenoid device, 5 housing, 6 core, 7 coil, 8 armature, 8a sliding portion, 8b upper surface portion, 9 valve device, 10 valve body, 11 valve holder, 11a guide portion, 12 valve seat, 12a valve seat portion 12d valve seat opening portion 13 nozzle hole plate 13a center portion 13b introduction portion 13b1 first side wall portion 13b2 second side wall portion 13c turning chamber 13c1 curved wall portion 13c2 facing wall portion , 14 injection hole portion, 14a center of injection hole portion, 15 ball, 15a chamfered portion, 16 compression spring,

Claims (5)

a valve seat having a valve seat opening through which fuel flows out; a valve body that opens and closes the valve seat opening; and an injection hole plate having a plurality of injection hole portions for injecting into the valve seat opening portion by moving the valve body in the axial direction of the valve seat based on an operation signal from an external control device. A fuel injection valve that opens and closes to control injection of the fuel from the injection hole,
The injection hole plate is
a plurality of swirl chambers arranged radially outside the valve seat opening on the end surface on the upstream side of the flow of the fuel;
a central portion connected to the valve seat opening;
a plurality of introduction portions for guiding the fuel from the central portion to each of the swirl chambers;
with
The introduction portion has a first side wall portion and a second side wall portion facing each other across a central axis of the introduction portion,
The center of the nozzle hole is
provided so as to be offset in the direction in which the first side wall portion exists with respect to the central axis of the introduction portion and coincide with the center of the swirl chamber;
The swirl chamber has a curved wall portion formed by a part of a virtual arc,
The curved wall portion is connected to the first side wall portion via a linearly extending facing wall portion,
When the shortest distance between the central axis of the introduction portion and the center of the nozzle hole is T, and the shortest distance between the center of the nozzle hole and the facing wall is G,
The facing wall portion is arranged within a range that satisfies [0.8T≦G≦1.2T].
A fuel injection valve characterized by: When the shortest distance between the central axis of the introduction portion and the first side wall portion is w, and the diameter of the injection hole portion is φDf,
The shortest distance T between the central axis of the introduction portion and the center of the injection hole portion is
is set to a value that satisfies [w<T≤w+φDf/2],
2. The fuel injection valve according to claim 1, characterized in that: When the length of the first side wall portion is L and the length of the second side wall portion is M,
The first sidewall portion and the second sidewall portion are configured to satisfy [0.1M ≤ L ≤ M-0.18],
3. The fuel injection valve according to claim 1 or 2, characterized in that: When the length of the second side wall portion is M and the radius of a virtual circumscribed circle that circumscribes the plurality of swirling chambers is r, the radius of the virtual circumscribed circle is

has a value that satisfies
4. The fuel injection valve according to any one of claims 1 to 3, characterized in that: The facing wall portion
provided at a position overlapping a tangent line circumscribing an imaginary circle whose radius is the shortest distance between the central axis of the introduction portion and the center of the injection hole and whose center coincides with the center of the injection hole;
5. The fuel injection valve according to any one of claims 2 to 4, characterized in that:

Images