JPH11200999A - Fuel injection valve for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the injection of fuel as a large lump remaining in the vicinity of a region where a valve element is seated on a seat face, suppress the generation of soot, etc., and stabilize the combustion. SOLUTION: This fuel injection valve is provided with a valve element 20 and a fuel passage formation member 30 forming a fuel passage 31 having an inlet part 31a at a predetermined position in a main body case 10 and an outlet part 31b at a position in the more upstream than a region where a contact part 20a comes into contact with a seat face 10b. In this case, a member like a flat plate 21 which is fixed on the valve element 20 integrally and opens and closes the inlet part 31a of the fuel passage formation member 30 in the direction of reciprocal movement of the valve element 20 is provided to shut off the communication between an internal space S of the main body case 10 and the fuel passage 31 in a condition in which the valve is closed and reduce a pressure in the fuel passage at least temporarily in accordance with the valve opening operation of the valve element 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel injection valve for an internal combustion engine, and more particularly, to a fuel injection valve for an internal combustion engine having a fuel passage for injecting fuel as a swirling flow.

[0002]

2. Description of the Related Art As a conventional fuel injection valve applied to an in-cylinder injection type internal combustion engine which injects fuel directly into a cylinder (combustion chamber), for example, JP-A-9-79106 and JP-A-9-79106 Japanese Patent Application Laid-Open No. 133061, JP-A-9-79108, and the like.

As shown in FIG. 14, the fuel injection valve disclosed in Japanese Patent Application Laid-Open No. 9-79106 has a body case 10 having a substantially cylindrical shape and having a fuel injection hole 100a at an end.
And a valve body 200 and the like, which is reciprocally housed inside the main body case 100 and opens and closes the injection hole 100a, and is formed at an end of the valve body 200 when not in operation. The conical tapered portion 200a is
b, the communication between the internal space S of the main body case 100 filled with fuel and the fuel injection holes 100a is cut off.

Here, when a fuel injection start signal is issued, an electromagnet (not shown) disposed above the valve body 200 is actuated to pull the valve body 200 upward (U direction).
As shown in FIG. 4, a fuel passage is formed between the tapered portion 200a of the valve body 200 and the seat surface 100b of the main body case 100, and the fuel pressurized to a predetermined value is applied to the outer peripheral surface of the valve body 200. The formed swirl flow path 200
b, the fuel is injected to the outside through the passage between the tapered portion 200a and the seat surface 100b and the fuel injection hole 100a.

At this time, a circumferential swirling force is applied to the fuel that has passed through the swirl flow forming passage 200b, so that the fuel injected from the fuel injection hole 100a is atomized and the spray shape is made uniform. become.

On the other hand, when the fuel injection stop signal is issued,
The electromagnet is in a non-operating state, and the valve body 200
0, the urging force of a return spring (not shown) and the pressure of the fuel cause the tapered portion 200a to move downward (in a direction opposite to the U direction), so that the tapered portion 200a
00b to shut off the fuel passage.

Further, as shown in FIG. 15, a fuel injection valve disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 9-133061 has a main body case 110 having a fuel injection hole 110a, a seat surface 110b, etc. A valve body 210 and the like, which are housed in a reciprocating manner in a reciprocating manner and have a substantially conical tapered portion 210a, a swirl flow forming passage 210b, and the like, are provided. Further, fuel is separately supplied to the main body case 110. A bypass passage 110c is formed.

In this fuel injection valve, when the valve element 210 is moved upward (U direction), the bypass passage 1
By supplying fuel from 10c, the characteristics of fuel spray,
The fuel spray angle and the like can be adjusted.

On the other hand, when not operating, the valve element 210
Moves downward (in the direction opposite to the U direction) so that the tapered portion 210a of the valve body 210
, And shut off the fuel passage.

Further, as shown in FIG. 16, the fuel injection valve disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 9-79108 has a fuel injection hole 120a having a substantially cylindrical shape and a tapered shape expanding outward at an end. And a valve housed in the main body case 120 and guided by the guide member 300 having a swirl (swirl) flow forming passage 300a so as to be reciprocally movable to open and close the fuel injection holes 120a. Body 220 etc., when not operating,
A substantially conical tapered portion 2 formed at the end of the valve body 220
20a is in direct contact with the fuel injection hole 120a as a seat surface to shut off the fuel passage.

[0011]

However, the above-mentioned conventional fuel injection valve has the following problems.

That is, in the fuel injection valve disclosed in Japanese Patent Application Laid-Open Nos. 9-79106 and 9-133061, the tapered portions 200a, 2
10a is the seat surface 100 of the main body cases 100 and 110
In the state where the fuel passage is shut off by sitting on the fuel injection holes 100a and 110b, the fuel is injected into the gap area A on the side of the fuel injection holes 100a and 110a, as shown in FIGS. The fuel that has lost the turning force is accumulated on the upstream side of the seating position and on the downstream side of the swirl flow forming passages 200b and 210b. At the time of the next fuel injection, the adhered or accumulated fuel is dispersed. There is a problem that the fuel particles are ejected as a lump of large-diameter particles, soot is generated due to an increase in penetration, or combustion becomes unstable.

Further, in the fuel injection valve disclosed in Japanese Patent Application Laid-Open No. 9-79108, since the valve body 220 is of an outward opening type, it is possible to prevent fuel from adhering to a region downstream from the above-described seating position. However, carbon or the like adheres to the outer edge region of the fuel injection hole 120a, and the carbon is caught in the sealing surface region by the upward and downward movement of the valve body 220, so that the taper portion 220a and the seat surface 120a adhere to each other. And the fuel leaks when the valve is closed. Further, the swirl flow forming passage 300 is located on the upstream side of the position where the tapered portion 220a of the valve element 220 is seated.
Similar to the above-described conventional technology, the fuel that has lost the turning force accumulates in the area B on the downstream side of a, and at the time of the next fuel injection, the accumulated fuel is ejected as a mass of fuel particles having a large particle diameter, Similarly, there is a problem in that soot is generated or combustion is destabilized due to an increase in penetration.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to prevent a lump of fuel particles from being ejected at an early stage of fuel injection, thereby providing a fuel. It is an object of the present invention to provide a fuel injection valve for an internal combustion engine capable of reducing the penetration of the fuel, suppressing the occurrence of soot, and stabilizing combustion.

[0015]

According to a first aspect of the present invention, there is provided a fuel injection valve for an internal combustion engine which has a substantially cylindrical shape to form an internal space for guiding fuel, and has a fuel injection hole and the fuel injection hole at one end. A main body case having a seat surface in an inner region following the hole, and a reciprocatingly disposed interior of the main body case and contacting the seat surface at one end to communicate the internal space of the main body case with the fuel injection hole. A valve body having a contact portion capable of shutting off, and a fuel having an inlet at a predetermined position in the main body case and an outlet at a position upstream of a region where the contact portion contacts the seat surface. A fuel passage forming member for forming a passage, wherein the abutting portion stops fuel injection from the fuel injection holes in a valve closed state in which the abutting portion abuts on the seat surface, and the abutting portion moves from the seat surface. In the opened valve state A fuel injection valve for an internal combustion engine that injects fuel from the fuel injection hole, wherein in the closed state, communication between the internal space of the main body case and the fuel passage is cut off, and the valve body is opened. The apparatus has a passage shut-off pressure reducing means for temporarily reducing at least the pressure in the fuel passage during operation.

A fuel injection valve for an internal combustion engine according to a second aspect of the present invention is the fuel injection valve for an internal combustion engine according to the first aspect, wherein the passage blocking pressure reducing means is integrally fixed to the valve body. Further, it is a flat plate-shaped member which comes into contact with and separates from the upper end surface of the fuel passage forming member in the reciprocating direction of the valve body to open and close the inlet of the fuel passage.

According to a third aspect of the present invention, there is provided a fuel injection valve for an internal combustion engine according to the first aspect, wherein the fuel passage forming member is in close contact with an outer peripheral surface of the valve body. A guide hole for reciprocatingly guiding the valve element, and the inlet formed to be open in a region radially outside the guide hole and upstream in the reciprocating direction of the valve element. The passage blocking pressure reducing means is integrally fixed to the valve body and extends to a region outside the inlet in the radial direction of the valve body, and the fuel passage extends in a reciprocating direction of the valve body. A substantially circular plate-shaped member that opens and closes an inlet portion of the valve body, and wherein the plate-shaped member and the fuel passage forming member are arranged to open the valve body in an entire circumferential area radially outside the inlet portion. In the radial direction throughout the specified travel distance Having a contact ring, such as remain in intimate contact with the stomach, has a configuration.

According to a fourth aspect of the present invention, there is provided the fuel injection valve for an internal combustion engine according to the first aspect, wherein the fuel passage forming member is in close contact with an outer peripheral surface of the valve body. A guide hole for reciprocatingly guiding the valve element, and the inlet formed to be open in a region radially outside the guide hole and upstream in the reciprocating direction of the valve element. The passage blocking pressure reducing means is integrally fixed to the valve body and extends to a region outside the inlet in the radial direction of the valve body, and the fuel passage extends in a reciprocating direction of the valve body. A substantially circular plate-shaped member that opens and closes an inlet portion of the valve body, and is positioned in a region outside the inlet portion in the radial direction of the valve element between the plate-shaped member and the fuel passage forming member. An annular elastic seal member, The seal member is disposed so as to keep in close contact with the lower surface of the flat member and the upper surface of the fuel passage forming member in the reciprocating direction of the valve during a predetermined movement distance due to the valve opening operation of the valve. It has a configuration.

The fuel injection valve for an internal combustion engine according to claim 5 of the present invention is the fuel injection valve for internal combustion engine according to claim 1, wherein the fuel passage forming member is in close contact with an outer peripheral surface of the valve body. A guide hole for reciprocatingly guiding the valve element, and the inlet formed to be open in a region radially outside the guide hole and upstream in the reciprocating direction of the valve element. The passage blocking and depressurizing means has a substantially central portion closely fixed to an outer peripheral portion of the valve body and a concave surface facing the fuel passage forming member, and an outer peripheral edge portion is radially larger than the inlet portion. A parabolic elastic seal member formed so as to be able to come into close contact with an upper end surface of the fuel passage forming member in an outer region; Change in the direction approaching the passage forming member And the outer peripheral edge portion is disposed so as to continue to be closely connected to the upper end surface of the fuel passage forming member during a predetermined movement distance due to the valve opening operation of the valve body. It has become.

[0020]

According to the fuel injection valve for an internal combustion engine according to the first aspect of the present invention, when the contact portion of the valve element is separated from the seat surface, that is, when the valve element starts the valve opening operation, Along with this valve opening operation, at least the pressure in the fuel passage is temporarily reduced by the passage blocking pressure reducing means.

At this time, in the valve-opened state, the abutting portion is attached to a region downstream of the seating region where the seating portion is seated on the seat surface (hereinafter referred to as “outside adhered fuel”) and upstream of the seating region. The fuel that has accumulated downstream of the outlet of the fuel passage (hereinafter referred to as the inner accumulated fuel) is temporarily sucked back into the fuel passage, that is, toward the upstream side by the above-described depressurizing action.

Thereafter, the internal space of the main body case filled with fuel is completely connected to the fuel passage, and at the same time, the high-pressure fuel is entrained by the sucked-back fuel and is injected at once from the fuel injection hole through the fuel passage. Will be done.

Accordingly, it is possible to prevent large lumps of fuel particles from being injected at the beginning of the injection. Thereby, the atomization of the injected fuel is promoted, and the variation in the amount of injected fuel is substantially suppressed, and the occurrence of soot and the like can be suppressed.
Further, stabilization of combustion, improvement of exhaust performance, and the like can be achieved.

According to the fuel injection valve for an internal combustion engine according to claim 2 of the present invention, when the contact portion of the valve element is separated from the seat surface, that is, when the valve element starts moving in the valve opening direction, The flat plate member closing the inlet of the fuel passage also starts to move together with the valve body. At this time, due to the movement of the flat plate member, the pressure in the fuel passage is temporarily reduced, and the outer adhering fuel and the seated region that have adhered to the passage downstream of the seated region communicating with the fuel passage are upstream of the seated region. Will be sucked back toward the upstream side.

After that, when the above-mentioned depressurizing action is weakened,
High-pressure fuel is injected at once from the fuel injection hole through the fuel passage.

Accordingly, it is possible to prevent large lumps of fuel particles from being injected at the beginning of the injection. As a result, atomization of the injected fuel, suppression of a substantial variation in the fuel injection amount, and the like are performed, and it is possible to achieve a reduction in the amount of soot and the like, a stable combustion, an improvement in exhaust performance, and the like.

Further, since a plate-like member which moves integrally with the valve element is adopted as the passage blocking pressure reducing means for generating the pressure reducing function, the structure is simplified and the valve opening operation of the valve element is reliably synchronized. A decompression effect can be produced. Thus, functional reliability can be ensured while achieving simplification of the device.

According to the fuel injection valve for an internal combustion engine according to the third aspect of the present invention, when the contact portion of the valve element is separated from the seat surface, that is, when the valve element starts moving in the valve opening direction, The plate-like member closing the inlet of the fuel passage also starts to move with this valve body to open the inlet.

During the movement of the plate member by a predetermined distance along with the movement of the valve body, the annular contact portion provides
The sealed space surrounded by the plate-shaped member, the fuel passage forming member, etc., increases in a state where the communication between the inner space of the main body case filled with fuel and the fuel passage is interrupted and the inlet portion communicates with the fuel passage. become.

By increasing the sealed space, the pressure reducing action in the fuel passage can be further increased, and the outer adhering fuel adhering downstream from the seating area and the inner pooled fuel accumulating upstream from the seating area can be removed. It can be sucked back more reliably.

Therefore, it is possible to more reliably prevent the injection of a large lump of fuel particles at the beginning of the injection. As a result, the atomization of the injected fuel, the suppression of the substantial variation in the fuel injection amount, etc., are performed more reliably, the generation amount of soot and the like is further reduced, the combustion is further stabilized, and the exhaust performance is improved. Further improvements and the like can be achieved.

According to the fuel injection valve for an internal combustion engine according to claim 4 of the present invention, when the contact portion of the valve element is separated from the seat surface, that is, when the valve element starts moving in the valve opening direction, The plate-like member closing the inlet of the fuel passage also starts to move with this valve body to open the inlet.

The annular elastic seal is in a state of being compressed while the flat member moves a predetermined distance with the movement of the valve body, that is, between the flat member and the fuel passage forming member. Until the member is completely elastically restored, the flat space member, the fuel passage forming member, the annular elastic seal member, etc. are kept in a state where the communication between the fuel passage and the inner space of the main body case filled with fuel is cut off. Is increased in a state where the closed space surrounded by is communicated with the entrance.

As described above, the pressure reduction action in the fuel passage can be further increased by the increase in the sealed space, and the fuel deposited outside the seating region and accumulated outside the seating region upstream from the seating region. The inner pool fuel can be sucked back more reliably.

Accordingly, in the early stage of the injection, it is possible to more reliably prevent the injection of a large lump of fuel particles as in the case described above. As a result, the atomization of the injected fuel, the suppression of the substantial variation in the fuel injection amount, etc., are performed more reliably, the generation amount of soot and the like is further reduced, the combustion is further stabilized, and the exhaust performance is improved. Further improvements and the like can be achieved.

According to the fuel injection valve for an internal combustion engine according to the fifth aspect of the present invention, when the contact portion of the valve element is separated from the seat surface, that is, when the valve element starts moving in the valve opening direction, The central portion of the parabolic elastic seal member positioned so that the outer peripheral edge portion contacts the upper end surface of the fuel passage forming member and covers the inlet portion of the fuel passage also starts to move together with the valve body.
At this time, since the central portion of the parabolic elastic seal member is elastically deformed in advance in the valve-closed state, the outer peripheral edge remains above the fuel passage forming member until the elastic deformation is completely restored. The parabolic elastic seal member and the fuel passage forming member are in close contact with the end face, and during this elastic return, the communication between the fuel passage and the internal space of the main body case filled with fuel is cut off. The enclosed space surrounded by the like increases in a state where it communicates with the entrance.

As described above, the pressure reduction effect in the fuel passage can be further increased by the increase in the sealed space, and the fuel deposited outside of the seating region and the fuel deposited outside and accumulated upstream of the seating region. The inner pool fuel can be sucked back more reliably.

Therefore, in the early stage of the injection, injection of a large lump of fuel particles can be more reliably prevented as in the case described above. As a result, the atomization of the injected fuel, the suppression of the substantial variation in the fuel injection amount, etc., are performed more reliably, the generation amount of soot and the like is further reduced, the combustion is further stabilized, and the exhaust performance is improved. Further improvements and the like can be achieved.

[0039]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 are schematic structural views showing a first embodiment of a fuel injection valve for an internal combustion engine according to the present invention. As shown in FIGS. 1 and 2, the fuel injection valve for an internal combustion engine according to the present embodiment has a substantially cylindrical shape, forms an internal space S for guiding fuel, and has a fuel injection hole 10a and a fuel injection hole 10 at one end. A main body case 10 having a substantially conical seat surface 10b in an inner region following the main surface 10a;
b, a contact portion 20 having a substantially frusto-conical shape capable of blocking communication between the internal space S of the main body case 10 and the fuel injection hole 10a.
a, and an inlet portion 31a at a predetermined position in the main body case 10 and the contact portion 20a is connected to the seat surface 10b.
, That is, a fuel passage forming member 30 forming a fuel passage 31 having an outlet portion 31b at a position upstream of the seating region M, and a main body case 10 in a valve closed state.
Of the fuel passage 31 and the valve body 20 as a passage blocking pressure reducing means for temporarily reducing at least the pressure in the fuel passage 31 with the valve opening operation of the valve body 20. Fixed plate member 21 and valve body 2
A stopper 11 for restricting the valve-opening movement of the valve body 20 to a predetermined range by contacting an umbrella portion 22 provided integrally with the stopper 11;
An electromagnetic coil and an armature (not shown) for moving the valve body 20 in the valve opening direction by energization when the valve is opened, and a return spring (not shown) for returning the valve body to the rest position when the valve is closed are provided as basic components. I have.

The fuel passage forming member 30 has a substantially cylindrical contour, and has a guide hole at a center portion thereof, which is in close contact with the outer peripheral surface of the valve body 20 and guides the valve body 20 to reciprocate in the axial direction thereof. 30b is formed, and on the end face 30a, an entrance portion 31a is opened at a position radially outside the guide hole 30b and at a position equivalent to the circumferential direction, and the guide hole 30b is formed.
b, four fuel passages 3 having an outlet portion 31b opened on the inner wall surface
1 is formed.

Further, the fuel passage 31 has a passage portion near the outlet portion 31b side extending in a tangential direction of the guide hole 30b, and the outlet portion 31b is provided with a contact portion 20a of the valve body 20. The opening is provided at a position upstream of the seating area M which is in contact with the seat surface 10b of the main body case 10.

Here, the fuel passage as described above is such that when the valve is opened, the fuel flowing through the fuel passage 31 forms a swirl flow when it is ejected from the outlet 31b. It is for.

The fuel passage forming member 30 is fixed in a state where its outer peripheral surface is in close contact with the inner peripheral surface of the main body case 10, so that fuel does not flow between the outer peripheral surface and the inner peripheral surface. It has become.

Although the fuel passage forming member 30 is formed separately from the main body case 10, it may be integrated with the main body case 10 as long as the fuel passage 31 and the like can be processed. .

Next, the operation of the fuel injection valve for an internal combustion engine according to this embodiment will be described.

In the closed state where fuel is not injected, that is, in the rest state, as shown in FIG. 3 (a), the outer peripheral surface of the contact portion 20a of the valve body 20 comes into close contact with the seat surface 10b.
The communication between the internal space S and the fuel injection hole 10a communicating with the outside is blocked. In this state, the downstream side of the seating region M where the abutting portion 20a abuts against the seat surface 10b, before adhering part of the fuel injected by the stroke as large lumps, to form an outer adhering fuel F ₁ ing. Further, on the downstream side of the outlet 31b of and the fuel passage 31 upstream of the seating region M is fuel that has lost the turning force is accumulated to form the inner reservoir fuel F _2.

Here, when the fuel injection start signal is issued, the valve body 2 is excited by the exciting action as shown in FIG.
0 starts moving in the valve opening direction (U direction). In synchronization with this, the flat plate-shaped member 21 which has been in close contact with the end face 30a of the fuel passage forming member 30 and has closed the inlet portion 31a also starts to move together with the valve body 20 and opens the inlet portion 31a. At this time, since the movement of the valve element 20, that is, the flat plate member 21 is performed instantaneously, the fuel passage 31 is moved from the end surface 21a of the flat plate member 21.
The space leading to the inside is temporarily decompressed by the suction action. At the same time, the contact portion 20a also has a seat surface 10b.
Disengaged from, since the gap is formed, the inner reservoir fuel F ₂ which has accumulated on the upstream side of the mass and the seating area of the outer adhering fuel F ₁ adhering to the downstream side of the seating area, generally Is sucked back into the fuel passage 31.

Thereafter, the valve element 20 stops and the above-mentioned suction or depressurizing action disappears, and at the same time, the high-pressure fuel filled in the internal space S passes through the fuel passage 31 and entrains the sucked-back fuel. At the outlet portion 31b as a swirl flow, and is injected at once from the fuel injection hole 10a.

Therefore, in the early stage of the injection, atomization of the injected fuel, suppression of substantial variation in the fuel injection amount, and the like are performed without injecting large lumps of fuel particles. In the case of an internal combustion engine that injects fuel into a cylinder, the amount of soot and the like is reduced, combustion is stabilized, and exhaust performance and the like are improved.

FIG. 4 is a schematic diagram showing a second embodiment of the fuel injection valve for an internal combustion engine according to the present invention. In the present embodiment, the first embodiment is the same as the first embodiment except that a part of the plate-shaped member 23 as the passage cut-off depressurization is configured to fit into the recess formed in the end face 30 a of the fuel passage forming member 30. Is the same as

That is, in this embodiment, the flat member 23 has a circular outer shape and the fuel passage forming member 30
Has a columnar convex portion 23a whose outer peripheral edge portion is reduced in diameter, while the fuel passage forming member 30
The end surface 30a has a columnar concave portion 32 that can fit the columnar convex portion 23a closely.
The inlet 31a of the fuel passage 31 is open on the bottom surface of the fuel passage 31. While the outer peripheral surface of the columnar convex portion 23a and the inner peripheral surface of the columnar concave portion 32 are moved by a predetermined distance in the valve opening direction in the entire peripheral region radially outside the inlet portion 31a of the fuel passage 31. It forms an annular contact portion that keeps in close contact with each other in the middle and radial directions.

Next, the operation of the fuel injection valve for an internal combustion engine according to this embodiment will be described. In the valve closed state in which fuel is not injected, that is, in the rest state, as shown in FIG. 5A, the outer peripheral surface of the contact portion 20a of the valve body 20 comes into close contact with the seat surface 10b, and The communication with the fuel injection hole 10a is cut off. In this state, the downstream side and the upstream side of the seating area M of contact portion 20a comes into contact with the seat surface 10b is outside deposition is part of the fuel injected in the pre-stroke fuel F ₁ and the inner reservoir fuel F ₂ Remains.

Here, when the fuel injection start signal is issued, the valve body 2 is excited by the exciting action as shown in FIG.
0 starts moving in the valve opening direction (U direction). In synchronization with this, the columnar projections 2 are
The plate-like member 23 into which the inlet 3a is tightly fitted and closes the inlet 31a also starts to move together with the valve element 20, and the inlet 31
Release a.

Until the plate member 23 moves a predetermined distance or more with the movement of the valve body 20, the outer peripheral surface of the columnar convex portion 23a, which is an annular contact portion, and the inner peripheral surface of the columnar concave portion 32. In close contact with the fuel passage 31 and the internal space S of the main body case 10 filled with fuel and the fuel passage 31 are closed. The sealed space V continues to increase while communicating with the entrance 31a.

At this time, the valve body 20, that is, the plate-like member 23
Is carried out instantaneously, so that the space in the fuel passage 31 is temporarily reduced in pressure by the suction action as long as the above-mentioned sealed space V continues to increase. At the same time, the contact portion 20a is also disengaged from the seat surface 10b, since the gap is formed, the outer remaining on the downstream side and the upstream side of the seating region M adhering fuel F ₁ and the inner reservoir fuel F ₂ Is temporarily more strongly sucked back into the fuel passage 31.

Thereafter, the columnar convex portion 23a separates from the columnar concave portion 32, and the above-mentioned suction action or decompression action disappears.
At the same time as the valve body 20 stops, the high-pressure fuel filled in the internal space S passes through the fuel passage 31 and is ejected as a swirl flow from the outlet portion 31b in a state in which the sucked back fuel F ₁ and F ₂ are involved. The fuel is injected at once from the fuel injection holes 10a.

Therefore, in the early stage of injection, atomization of the injected fuel and suppression of substantial variation in the fuel injection amount are performed without injecting large lumps of fuel particles. In the case of an internal combustion engine that injects fuel into a cylinder, the amount of soot and the like is reduced, combustion is stabilized, and exhaust performance and the like are improved.

FIG. 6 shows a third embodiment similar to the embodiment shown in FIG.
It is a schematic structure figure showing an example of. In the present embodiment, a part of the flat plate member 24 as the passage blocking and depressurizing means fits into the concave portion formed on the upper end surface of the fuel passage forming member 30 and the concave portion formed on the lower surface of the flat plate member 24. The configuration is the same as that of the first embodiment, except that a protrusion formed on the upper end surface of the fuel passage forming member 30 is fitted into the second embodiment.

That is, in this embodiment, the flat member 24 has a circular outer shape and the fuel passage forming member 30
Annular convex portion 24 whose outer peripheral edge protrudes on the side opposite to
On the other hand, the fuel passage forming member 30 has an annular concave portion 33 on the upper end surface 30a to which the annular convex portion 24a can be fitted tightly. The entrance 31a of the passage 31 is open. The outer peripheral surface of the annular convex portion 24a and the outer inner wall surface of the annular concave portion 33 move while the valve body 20 moves a predetermined distance in the valve opening direction in the entire radial region outside the inlet portion 31a of the fuel passage 31. It forms an annular contact portion that keeps in close contact with each other in the middle and radial directions.

In a region radially inside the inlet portion 31a of the fuel passage 31, the fuel passage forming member 30 is
It has a second annular projection 34 projecting from its upper end surface 30a, while the lower surface of the
Has a second annular concave portion 24b into which the annular convex portion 34 can be fitted.

Next, the operation of the fuel injection valve for an internal combustion engine according to this embodiment will be described. In the closed state where fuel is not injected, that is, in the rest state, as shown in FIG. 7A, the outer peripheral surface of the contact portion 20a of the valve body 20 comes into close contact with the seat surface 10b, and the internal space S and the outside are The communication with the fuel injection hole 10a is cut off. In this state, the downstream side and the upstream side of the seating area M of contact portion 20a comes into contact with the seat surface 10b is outside deposition is part of the fuel injected in the pre-stroke fuel F ₁ and the inner reservoir fuel F ₂ Remains.

Here, when the fuel injection start signal is issued, the valve body 2 is excited by the exciting action as shown in FIG.
0 starts moving in the valve opening direction (U direction). In synchronization with this, the plate-like member 24, whose annular protrusion 24 a has been tightly fitted into the annular recess 33 on the upper end surface of the fuel passage forming member 30 and closed the inlet 31 a, also starts moving together with the valve element 20. Then, the entrance 31a is opened.

Until the flat plate member 24 moves a predetermined distance or more along with the movement of the valve body 20, the outer peripheral surface of the annular convex portion 24 a which is the annular contact portion and the outer inner wall surface of the annular concave portion 33. And the second annular recess 24b on the lower surface of the plate-like member 24 while the communication between the fuel passage 31 and the internal space S of the main body case 10 filled with fuel is cut off. The closed space V surrounded by the second annular projection 34 and the like on the upper end surface of the passage forming member 30 forms the entrance portion 31a.
Continue to increase in communication with.

At this time, the valve body 20, that is, the plate-like member 24
Is carried out instantaneously, so that the space in the fuel passage 31 is temporarily reduced in pressure by the suction action as long as the above-mentioned sealed space V continues to increase. At the same time, the contact portion 20a is also disengaged from the seat surface 10b, since the gap is formed, the outer remaining on the downstream side and the upstream side of the seating region M adhering fuel F ₁ and the inner reservoir fuel F ₂ Is temporarily more strongly sucked back into the fuel passage 31.

Thereafter, the annular convex portion 24a separates from the annular concave portion 33, and the above-mentioned suction action or depressurization action disappears.
At the same time as the valve body 20 stops, the high-pressure fuel filled in the internal space S passes through the fuel passage 31 and is ejected as a swirl flow from the outlet portion 31b in a state in which the sucked back fuel F ₁ and F ₂ are involved. The fuel is injected at once from the fuel injection holes 10a.

Therefore, in the early stage of the injection, atomization of the injected fuel, suppression of substantial variation in the fuel injection amount, etc. are performed without injecting large lumps of fuel particles. In the case of an internal combustion engine that injects fuel into a cylinder, the amount of soot and the like is reduced, combustion is stabilized, and exhaust performance and the like are improved.

FIG. 8 is a schematic diagram showing a fourth embodiment of the fuel injection valve for an internal combustion engine according to the present invention. In the present embodiment, between the flat plate member 21 and the fuel passage forming member 30,
It is the same as the first embodiment except that an annular elastic seal member is provided.

That is, in the present embodiment, the annular groove 35 is provided on the upper end surface 30a of the fuel passage forming member 30 in a region outside the inlet 31a of the fuel passage 31 in the radial direction of the valve body 20. , For this annular groove 35,
A rubber ring 40 is disposed as an annular elastic seal member.

The rubber ring 40 is partially buried in the annular groove 35 in a state where the rubber ring 40 is not subjected to the compressive force by the flat plate member 21, and the other portion has a predetermined height from the upper end surface 30 a of the fuel passage forming member 30. It is formed so as to protrude.

When the valve is closed, the flat plate member 2
The first end surface 21a compresses and deforms the rubber ring 40 and abuts against the end surface 30a of the fuel passage forming member 30 to close the inlet portion 31a of the fuel passage 31.

Next, the operation of the fuel injection valve for an internal combustion engine according to this embodiment will be described. In the closed state in which fuel is not injected, that is, in the rest state, as shown in FIG. 9A, the outer peripheral surface of the contact portion 20a of the valve body 20 closely contacts the seat surface 10b, and The communication with the fuel injection hole 10a is cut off. In this state, the downstream side and the upstream side of the seating area M of contact portion 20a comes into contact with the seat surface 10b is outside deposition is part of the fuel injected in the pre-stroke fuel F ₁ and the inner reservoir fuel F ₂ Remains.

Here, when the fuel injection start signal is issued, the valve body 2 is excited by the exciting action as shown in FIG.
0 starts moving in the valve opening direction (U direction). In synchronization with this, the flat plate-shaped member 21 which has been in close contact with the end face 30a of the fuel passage forming member 30 and has closed the inlet portion 31a also starts to move together with the valve body 20 and opens the inlet portion 31a.

During the movement of the plate member 21 over a predetermined distance with the movement of the valve body, the compression is performed between the lower surface of the plate member 21 and the upper end surface of the fuel passage forming member 30. Until the rubber ring 40 which has been in the closed state is completely elastically restored, the flat plate-like member is kept in a state where the communication between the internal space S of the main body case 10 filled with fuel and the fuel passage 31 is cut off. 21, fuel passage forming member 3
0, the sealed space V surrounded by the rubber ring 40 and the like continues to increase while communicating with the inlet 31a.

At this time, the valve body 20, that is, the flat member 21
As the rubber ring 40 elastically returns following the movement of the closed space V, the space in the fuel passage 31 is temporarily reduced in pressure by the suction action as long as the above-mentioned sealed space V continues to increase. At the same time
Abutment 20a be separated from the seat surface 10b, since the gap is formed, the outer remaining on the downstream side and the upstream side of the seating region M adhering fuel F ₁ and the inner reservoir fuel F ₂
Is temporarily sucked back into the fuel passage 31.

Thereafter, the flat plate-like member 21 is
And the high-pressure fuel filled in the internal space S passes through the fuel passage 31 and the fuel F ₁ , F sucked back at the same time as the valve body 20 stops. ₂ is swirled out of the outlet 31b as a swirl flow, and is injected at once from the fuel injection holes 10a.

Therefore, in the initial stage of injection, atomization of the injected fuel and suppression of substantial variation in the fuel injection amount are performed without injecting large lumps of fuel particles. In the case of an internal combustion engine that injects fuel into a cylinder, the amount of soot and the like is reduced, combustion is stabilized, and exhaust performance and the like are improved.

FIG. 10 is a schematic diagram showing a fifth embodiment of the fuel injection valve for an internal combustion engine according to the present invention. This embodiment is the same as the first embodiment except that a parabolic elastic seal member that is elastically deformed is provided as the passage blocking pressure reducing means.

That is, in the present embodiment, as shown in FIG. 10, a circular rib 25 is formed on the valve body 20, and an approximately central portion 50 a
Are closely fixed, and a parabola-shaped elastic seal member 50 is formed, the concave surface of which is opposed to the fuel passage forming member 30.

The parabolic elastic sealing member 50
The outer peripheral edge portion 50b is in close contact with the upper end surface 30a of the fuel passage forming member 30 in a region radially outside the inlet portion 31a of the fuel passage 31 which is opened at the upper end surface 30a of the fuel passage forming member 30. Thus, it is formed so as to cover the inlet 31a.

The parabolic elastic sealing member 5
0 is held in a state where the substantially central portion 50a is deformed in a direction approaching the fuel passage forming member 30 in the valve closed state,
Further, while the valve body 20 moves a predetermined distance by the valve opening operation, the outer peripheral edge portion 50b is connected to the upper end surface 3 of the fuel passage forming member 30.
0a is kept in close contact.

Next, the operation of the fuel injection valve for an internal combustion engine according to this embodiment will be described.

In the closed state where fuel is not injected, that is, in the rest state, as shown in FIG. 11A, the outer peripheral surface of the contact portion 20a of the valve body 20 comes into close contact with the seat surface 10b, and the internal space S And the fuel injection hole 10a communicating with the outside is blocked. In this state, the downstream side and the upstream side of the seating area M of contact portion 20a comes into contact with the seat surface 10b is outside deposition is part of the fuel injected in the pre-stroke fuel F ₁ and the inner reservoir fuel F ₂ Remains.

Here, when the fuel injection start signal is issued, the valve element 20 starts to move in the valve opening direction (U direction) as shown in FIG. In synchronization with this, the substantially central portion 50a of the parabolic elastic seal member 50
Starts moving together with the valve element 20.

Since the central portion 50a of the parabolic elastic seal member 50 is elastically deformed in advance in the valve-closed state, the outer peripheral edge 50b is formed in the fuel passage until the elastic deformation is completely restored. Upper end surface 3 of member 30
While being in close contact with Oa, the elastic return continues from the central portion 50a outward. During this elastic return, the inner space S of the main body case 10 filled with fuel and the fuel passage 3
The airtight space V surrounded by the parabolic elastic seal member 50, the fuel passage forming member 30, and the like continues to increase in a state where the communication with the inlet portion 31a is communicated, while the communication with the first member 1 is interrupted.

At this time, with the movement of the valve body 20, the parabolic elastic seal member 50 elastically returns to the closed space V.
As long as the increase continues, the space in the fuel passage 31 is temporarily reduced in pressure by the suction action. At the same time, contact part 2
0a from the fact that the gap disengaged from the seat surface 10b is formed, the outer adhering fuel F ₁ and the inner reservoir fuel F ₂ remaining in the downstream and upstream side of the seating region M temporarily the fuel passage It is sucked back into 31.

Thereafter, the parabolic elastic seal member 50 is completely elastically restored, and its outer peripheral edge 50b is separated from the upper end surface 30a of the fuel passage forming member 30, so that the above-mentioned suction or depressurizing action is extinguished. At the same time when the body 20 stops, the high-pressure fuel filled in the internal space S is supplied to the fuel passage 3.
1, the fuel F ₁ , F ₂ , which has been sucked back, is ejected as a swirl flow from the outlet portion 31 b in a state where the fuel F ₁ , F ₂ is entrained, and is injected at once from the fuel injection hole 10 a.

Therefore, in the early stage of the injection, atomization of the injected fuel and suppression of a substantial variation in the fuel injection amount are performed without injecting large lumps of fuel particles. In the case of an internal combustion engine that injects fuel into a cylinder, the amount of soot and the like is reduced, combustion is stabilized, and exhaust performance and the like are improved.

In each of the embodiments described above, the valve 2
FIG. 12 shows the fuel pressure in the seating region where the zero contact portion 20a contacts the seat surface 10b in relation to the passage of time, that is, the movement amount (lift amount) of the valve body 20.

As shown in FIG. 12, the fuel pressure in the vicinity of the seating region temporarily decreases in the initial stage when the valve body 20 moves (lifts), and then rapidly as the valve body 20 moves. Reach the fuel pressure within.

FIG. 13 shows the spray form of the fuel injection valve for an internal combustion engine and the conventional fuel injection valve for an internal combustion engine in each embodiment according to the present invention.

That is, in the conventional device, FIG.
As shown in FIG. 13, a portion with a high fuel density is injected into a substantially central portion of the spray in a state in which the fuel density is long, but according to the present invention, as shown in FIG. The fuel is injected in a substantially uniform hollow cone shape, and the atomization of the fuel spray is promoted.

The fuel injection valve for an internal combustion engine described above is not only applied to an in-cylinder injection type internal combustion engine that directly injects fuel into a cylinder, but is applicable to an internal combustion engine that injects fuel into an intake pipe. Is also applicable.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a fuel injection valve for an internal combustion engine according to the present invention.

FIG. 2 is a sectional view taken along the line EE in FIG.

3A and 3B are diagrams for explaining the operation of the fuel injection valve for an internal combustion engine shown in FIG. 1, wherein FIG. 3A shows a valve closed state, and FIG. 3B shows a state during a valve opening operation.

FIG. 4 is a schematic configuration diagram showing a second embodiment of a fuel injection valve for an internal combustion engine according to the present invention.

5A and 5B are diagrams for explaining the operation of the fuel injection valve for an internal combustion engine shown in FIG. 4, in which FIG. 5A shows a valve closed state, and FIG. 5B shows a state during a valve opening operation.

FIG. 6 is a schematic configuration diagram showing a third embodiment of a fuel injection valve for an internal combustion engine according to the present invention.

7A and 7B are diagrams for explaining the operation of the fuel injection valve for an internal combustion engine shown in FIG. 6, wherein FIG. 7A shows a valve closed state, and FIG. 7B shows a state during a valve opening operation.

FIG. 8 is a schematic configuration diagram showing a fourth embodiment of the fuel injection valve for an internal combustion engine according to the present invention.

9A and 9B are diagrams for explaining the operation of the fuel injection valve for an internal combustion engine shown in FIG. 8, wherein FIG. 9A shows a valve closed state, and FIG. 9B shows a state during a valve opening operation.

FIG. 10 shows a fifth embodiment of the fuel injection valve for an internal combustion engine according to the present invention.
It is a schematic structure figure showing an example of.

11A and 11B are diagrams illustrating the operation of the fuel injection valve for an internal combustion engine shown in FIG. 10, in which FIG. 11A shows a valve closed state, and FIG. 11B shows a state during a valve opening operation.

FIG. 12 is a graph showing a change in fuel pressure in the vicinity of a seating area in the fuel injection valve for an internal combustion engine according to the present invention.

13A and 13B are diagrams showing a spray form injected from a fuel injection valve for an internal combustion engine, wherein FIG. 13A is a conventional spray form, and FIG.
Shows a spray form according to the present invention.

FIG. 14 is a schematic configuration diagram showing a conventional fuel injection valve for an internal combustion engine.

FIG. 15 is a schematic configuration diagram showing a conventional fuel injection valve for an internal combustion engine.

FIG. 16 is a schematic configuration diagram showing a conventional fuel injection valve for an internal combustion engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Main body case 10a Fuel injection hole 10b Seat surface 11 Stopper 20 Valve element 20a Contact portion 21 Flat member (passage depressurizing means) 21a End face (lower surface) 22 Head 23 Flat plate member (passage depressurizing means) 23a Column-shaped convex Portion (annular contact portion) 24 Flat member (passage blocking pressure reducing means) 24a Annular convex portion (annular contact portion) 24b Second annular concave portion 25 Circular rib 30 Fuel passage forming member 30a Upper end surface 30b Guide hole 31 Fuel passage 31a Inlet Portion 31b Outlet portion 32 Columnar concave portion (annular contact portion) 34 Second annular convex portion 35 Annular groove 40 Rubber ring (annular elastic seal member) 50 Parabolic elastic seal member (passage depressurizing means) 50a Central portion 50b Outer peripheral edge portion

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 61/12 F02M 61/12

Claims (5)

[Claims] 1. A main body case having a substantially cylindrical shape to form an internal space for guiding fuel and having a fuel injection hole at one end and a seat surface in an inner area following the fuel injection hole, and reciprocating in the main body case. A valve body movably disposed and having an abutting portion at one end which can abut on the seat surface to interrupt communication between the internal space of the main body case and the fuel injection hole; and a predetermined position in the main body case. A fuel passage forming member that forms a fuel passage having an outlet at a position upstream of a region where the abutting portion abuts the seat surface, wherein the abutting portion abuts the seat surface. Fuel injection for an internal combustion engine that stops injection of fuel from the fuel injection hole in a valve closed state in which the fuel injection hole is in contact with the fuel injection hole and injects fuel from the fuel injection hole in an open state in which the abutment portion is separated from the seat surface. With a valve In the closed state, the communication between the internal space of the main body case and the fuel passage is interrupted, and at least the pressure in the fuel passage is temporarily reduced with the opening operation of the valve body. A fuel injection valve for an internal combustion engine, comprising: a passage cut-off pressure reducing means for causing the fuel to flow. 2. The fuel supply system according to claim 2, wherein the passage blocking pressure reducing means is integrally fixed to the valve body and abuts on and separates from an upper end surface of the fuel passage forming member in a reciprocating direction of the valve body. A flat member that opens and closes the entrance of the passage,
The fuel injection valve for an internal combustion engine according to claim 1, wherein: 3. The fuel passage forming member includes a guide hole that closely contacts an outer peripheral surface of the valve body and guides the valve body in a reciprocating manner, and a region radially outside the guide hole and the valve. The inlet portion formed so as to open toward the upstream side in the reciprocating direction of the body, wherein the passage blocking and depressurizing means is integrally fixed to the valve body and in the radial direction of the valve body. And a substantially circular plate-shaped member that opens and closes an inlet of the fuel passage in a reciprocating direction of the valve body while extending to a region outside the inlet. Has an annular contact portion that keeps in close contact with each other in the radial direction during a predetermined movement distance due to the valve opening operation of the valve body in the entire peripheral region radially outside the inlet portion. The internal combustion engine according to claim 1, wherein Fuel injection valve. 4. The valve according to claim 1, wherein the fuel passage forming member includes a guide hole which closely contacts an outer peripheral surface of the valve body and guides the valve body in a reciprocating manner, and a region radially outside the guide hole and the valve. The inlet portion formed so as to open toward the upstream side in the reciprocating direction of the body, wherein the passage blocking and depressurizing means is integrally fixed to the valve body and in the radial direction of the valve body. And a substantially circular plate-shaped member that opens and closes an inlet of the fuel passage in a reciprocating direction of the valve body while extending to a region outside the inlet. And an annular elastic seal member positioned in a region outside the inlet portion in the radial direction of the valve body, wherein the annular elastic seal member moves a predetermined distance by a valve opening operation of the valve body. During the reciprocating direction of the valve 2. The fuel injection valve for an internal combustion engine according to claim 1, wherein the fuel injection valve is arranged so as to keep in close contact with the lower surface of the flat member and the upper surface of the fuel passage forming member. 5. The fuel passage forming member includes a guide hole that closely contacts an outer peripheral surface of the valve body and guides the valve body in a reciprocating manner, and a region radially outside the guide hole and the valve. The inlet portion formed so as to open toward the upstream side in the reciprocating direction of the body, wherein the passage blocking and depressurizing means has a substantially central portion closely fixed to an outer peripheral portion of the valve body and a concave surface. A parabolic elastic seal member formed so as to face the fuel passage forming member and to be able to come into intimate contact with the end face of the fuel passage forming member in a region whose outer peripheral edge is radially outside the inlet portion. The parabolic elastic seal member is held in a state where a substantially central portion is deformed in a direction approaching the fuel passage forming member in a valve closed state, and has a predetermined moving distance due to a valve opening operation of the valve body. All the way, the outer peripheral edge is Is arranged to remain closely connected to the upper end surface of the charge path forming member,
The fuel injection valve for an internal combustion engine according to claim 1, wherein: