JPH08177689A - Fuel supply device for internal combustion engine - Google Patents

Abstract

PURPOSE: To eliminate sticking and dripping fuel so as to accelerate atomization, by arranging a valve opening/closing mechanism in a point end of an extension pipe, also arranging an atomization means opposed to a fuel injection hole, in an injection valve of using the extension pipe positioned to just under a head part of an intake valve. CONSTITUTION: In a solenoid operated fuel injection valve 20, fuel, successively from an upper part of a fixed core 21 passing through a filter 24, adjusting pipe 11, orifice 12 in a movable core 7, extension pipe 4 and a needle 1, is supplied to the upstream of a valve seat 4c. By carrying a current in an electromagnetic coil 33 through a terminal 34 of a connector 35a, electromagnetic force is generated in the electromagnetic coil 33, to lift the movable core 7 and the needle 1 integrally formed with this movable core till colliding against the fixed core 21 against a spring 13. Thereafter, fuel is made to pass through a fuel injection hole from a clearance between a seat part 14 and the valve seat 4c in the needle 1, to jet fuel from each hole 17a of a plate 17 atomized also injected to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for an internal combustion engine, and more particularly to a system for injecting and supplying fuel to an intake passage in a gasoline engine for automobiles.

[0002]

2. Description of the Related Art In order to stabilize the combustion of an internal combustion engine, a fuel supply device for ejecting fuel injected from an air assist fuel injection valve into a combustion chamber through an extension pipe is disclosed in Japanese Patent Laid-Open No. 6-108.
No. 06 publication. The fuel injection valve disclosed in the publication has an extension pipe connected to an injection hole at the tip of the fuel injection valve,
The tip nozzle is opened at a position directly above the umbrella of each intake valve, and the tip nozzle of the extension tube is integrally formed with a conical end-spreading cylinder whose diameter gradually increases from upstream to downstream. As a result, the fuel spray ejected from the tip injection port of the fuel injection valve at the opening timing of the intake valve is diffused into the combustion chamber through the extension pipe with an appropriate spread, and the mixing of the fuel spray and the intake air is promoted. Since the space floating ratio of the fuel flowing into the combustion chamber becomes high and a rich air-fuel mixture is formed, the combustion can be stabilized.

[0003]

In the above prior art, when the air pump for supplying the assist air is abolished in order to reduce the cost, or the air pump does not operate normally for some reason, the supply pressure of the assist air decreases. In this case, since the air assist action on the fuel injection valve disappears, the fuel adheres to the inner surface of the extension pipe and the flow velocity of the spray in the extension pipe decreases, so that the droplets of the spray become large and the fuel flows from the tip of the extension pipe. This causes the problem of the drooping.

In view of this problem in the prior art, the present invention has an object to solve the above problems in the prior art by improving the structure of the injection valve with extension pipe.

[0005]

Therefore, according to the present invention, the fuel injection hole at the tip of the fuel injection valve is provided directly above the umbrella portion of the intake valve through the extension pipe, and from that position to the combustion chamber. Is configured to inject fuel spray toward the extension pipe, and a valve opening / closing mechanism for opening / closing the fuel injection hole is provided at the tip end portion of the extension pipe to control injection and shutoff of fuel at the tip end portion of the extension pipe. A fuel supply device for an internal combustion engine is provided.

[0006]

[Function] Not only the tip of the extension pipe extends to a position directly above the intake valve, but also the fuel injection hole at the tip is opened and closed by the valve, so fuel is injected at the tip of the extension pipe. When jetted at high speed from the hole, it will be atomized. Therefore, unlike the conventional one in which the fuel spray is guided by the extension pipe, the adhesion of the fuel spray to the inner wall surface of the extension pipe and
It is possible to smoothly inject fuel without causing the problem of fuel dripping from the tip of the extension pipe.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the illustrated embodiment, the present invention is applied to a fuel injection valve of a fuel supply system for a gasoline engine. As shown in FIG. 1, the fuel injection valve 20 has a substantially cylindrical yoke 26 made of a plate-shaped magnetic material as a main component.
A fixed iron core 21, a movable core 7, a needle 1, an extension pipe 4, a magnetic pipe 8a, a non-magnetic pipe 8b, etc. are provided in the axial direction.

A spool 3 made of resin is provided on the inner circumference of the yoke 26.
2 is fixed. The spool 32 has an electromagnetic coil 33.
Is wound. The cylindrical fixed iron core 21 made of a magnetic material is inserted into the spool 32 so as to project from above the spool 32. And the fixed iron core 2
A non-magnetic pipe 8b is connected to the lower part of 1. The non-magnetic pipe 8b is formed in a stepped pipe shape including a large diameter portion 81 and a small diameter portion 82. The large-diameter portion 81 is connected to the lower portion of the fixed iron core 21 and is provided so as to partially project from the lower end of the fixed iron core 21. Further, at the lower end of the small diameter portion 82 of the non-magnetic pipe 8b, a magnetic pipe 8a made of a magnetic material and formed into a stepped pipe shape.
The small-diameter portion 83 of is connected. The inner diameter of the small diameter portion 82 of the non-magnetic pipe 8b is set to be slightly smaller than the inner diameter of the small diameter portion 83 of the magnetic pipe 8a. Inside the valve body 4b joined to the tip of the extension pipe 4, a cylindrical surface 4d on which a steel ball 1b of the needle 1 described later slides and a seat 14 on which the seat portion 14 of the steel ball 1b of the needle 1 is seated. 4c are formed. Further, a fuel injection hole 36 is formed at the center of the bottom.

Next, a cylindrical movable core 7 made of a magnetic material is provided in the space inside the non-magnetic pipe 8b and the magnetic pipe 8a. The outer diameter of the movable core 7 is set to be slightly smaller than the inner diameter of the small diameter portion 82 of the nonmagnetic pipe 8b, and the movable core 7 is slidably inserted into the nonmagnetic pipe 8b. The upper end surface of the movable core 7 is provided so as to face the lower end surface of the fixed iron core 21 with a predetermined gap. Further, the needle 1 is connected to the inner periphery of the lower end of the movable core 7.

The needle 1 is a hollow cylindrical relatively inexpensive pipe member 1a having a plurality of holes 5a for guiding the fuel to the injection hole 36 and for reducing the weight of the needle itself. As shown in FIGS. 2 and 3, the pipe material 1a
It is made up of steel balls 1b which are joined to the tip end of each of the steel balls 1 and are chamfered at four locations in order to guide the fuel to the injection holes 36. Then, the joint 1 and the inner peripheral surface of the movable core 7 are laser-welded, so that the needle 1 and the movable core 7 are connected as one body. The tip surface 1c of the pipe material 1a
Has a chamfered shape as shown in FIG. 5 for joining with the steel ball 1b. Further, instead of providing a plurality of holes 5a in the pipe material 1a, a plurality of slits 1d may be provided as shown in FIG. 6 for the same purpose. The extension pipe 4 is formed by joining a relatively inexpensive pipe material 4a having a hollow cylindrical shape and a valve body 4b that has been precision processed. Here, the pipe material 4a and the valve body 4 that form the extension pipe 4
b and the pipe material 1a used for the needle 1 are materials having different coefficients of thermal expansion, when the fuel injection valve is mounted on an internal combustion engine, the respective materials are deformed differently due to the shape change due to heat. Therefore, the dimension of the air gap 7b between the movable core 7 and the fixed iron core 21 is changed, and the lift amount of the needle 1 is changed, so that the fuel injection amount of the injection valve 20 is also changed. For this reason,
A pipe member 4a, a valve body 4b, which constitute the extension pipe 4,
The pipe material 1a of the needle 1 is made of a material having the same coefficient of thermal expansion.

On the upper end surface of the movable core 7, the needle 1 welded and fixed to the movable core 7 is urged downward in the figure, and the spring 13 for seating the seat portion 14 of the needle 1 on the valve seat 4c of the extension pipe 4 is provided. Is provided. The upper end of the spring 13 projects from the inside of the movable core 7 to the inside of the fixed iron core 21, and is supported by the lower end of the adjusting pipe 11 inserted and fixed in the fixed iron core 21. Then, the biasing force of the spring 13 is adjusted by adjusting the axial position of the adjusting pipe 11. Further, an orifice 12 for adjusting the static injection amount of the injection valve 20 is formed inside the movable core 7.

Above the fixed iron core 21, fuel is pumped from the fuel tank by a fuel pump or the like, and the fuel injection valve 20
A filter 24 for removing dust and the like in the fuel flowing into the inside is provided. Therefore, the fuel flowing into the fixed iron core 21 passes through the adjusting pipe 11, the orifice 12 of the movable core 7, the extension pipe 4 and the needle 1, and reaches the fuel injection hole 36.

Further, the substantially cylindrical outer peripheral portion 3 other than the extension pipe 4
5 is made of synthetic resin including the portion of the connector 35a. The terminal 34 electrically connected to the electromagnetic coil 33 is embedded in the connector 35a and the spool 32. The terminal 34 is connected to an electronic control unit (not shown) via a wire harness, and an exciting current flows through the electromagnetic coil 33 via the terminal 34 by the electronic control unit. As a result, the needle 1 and the movable core 7 are attracted toward the fixed iron core 21 against the biasing force of the spring 28.

Further, on the outer peripheral bottom of the extension pipe 4, as shown in FIG.
A disk-shaped plate 1 shown enlarged in (a) and (b)
7 is inset. A plurality of holes 17a are formed in the center of the plate 17. In the fuel injection valve 20 of the illustrated embodiment, the non-magnetic pipe 8b and the magnetic pipe 8 are
a, the extension tube 4 constitutes a housing. The operation of the electromagnetic fuel injection valve 20 having the above configuration will be described. The fuel pressurized to a constant pressure by a fuel pump and a pressure regulator (not shown) flows from the upper part of the fixed iron core 21 to the filter 24, the adjusting pipe 11, the orifice 12 inside the movable core 7, the extension pipe 4 and the inside of the needle 1. After passing through, it is supplied upstream of the valve seat 4c. When the electromagnetic coil 33 is energized by the electronic control unit (not shown) via the terminal 34 of the connector 35a, the electromagnetic coil 33 generates an electromagnetic force (in this case, an attractive force), and the electromagnetic force causes the movable core 7 to move. The needle 1 joined to and integrated with it rises to a position where the movable core 7 and the fixed iron core 21 collide against the biasing force of the spring 13. Then, the needle 1 and the movable core 7 are held at this position by the electromagnetic force of the electromagnetic coil 33. After that, when the injection signal to the electromagnetic coil 33 is no longer output and the electromagnetic force ceases to act, the needle 1 descends due to the urging force of the spring 13, and the seat portion 14 of the steel ball 1b at the tip ends the tip of the extension tube 4. It comes into contact with the valve seat 4c formed on the valve body 4b.

Therefore, the fuel passes through the fuel injection hole 36 from the gap between the seat portion 14 of the needle 1 and the valve seat 4c until the needle 1 ascends and descends, and a plurality of fuels are formed at the center of the plate 17. By ejecting from the holes 17a, the fuels collide with each other to be atomized, and the fuel spray is ejected toward the back surface of the intake valve of the internal combustion engine and as much as possible not to adhere to the inner wall surface of the intake manifold (not shown). Further, instead of using the plate 17 as the fuel atomizing means, as shown in FIG. 7, a hook 37 is attached to the tip of the extension pipe 4 so as to face the fuel injection hole 36, and the injection hole 3
It is also possible to collide the fuel spray discharged from 6 with the hook-shaped body 37 to atomize the fuel.

In the embodiment shown in FIGS. 1 to 8, the needle 1 is in the form of a ball valve using a steel ball 1b, but this is the case in the fuel injection valve 20 using the long extension pipe 4. Since the needle 1 longer than the normal one is used, the inclination of the needle when the seat portion at the tip of the needle 1 is seated on the valve seat becomes a problem, and as shown in FIGS. 8 (a) and 8 (b), In the valve using the needle 1'having a conical tip, the valve body 4b 'is formed by the inclination of the needle 1'.
The seating on the valve seat 4c 'may be incomplete, but as shown in FIGS. 8 (c) and 8 (d), if a ball valve is used, even if the pipe material 1a of the needle 1 is inclined, This is because the ball 1b can sit on the valve seat 4c.

Next, another embodiment of the fuel injection valve will be described. In the fuel injection valve 20b shown in FIG. 9, a substantially cylindrical yoke 26, an axial fixed iron core 21, a synthetic resin spool 32, an electromagnetic coil 33, a synthetic resin outer peripheral portion 35,
The connector 35a, the terminal 34, and the plate 17 may be substantially the same as the fuel injection valve 20 of the above-described embodiment, and the operation thereof is also the same.

The magnetic core 81 is fixed inside the fixed iron core 21, and is chamfered so that the fuel can pass therethrough. A spring receiving extension shaft 51 is fixed and connected to the lower portion of the magnetic core 81. The non-magnetic ring 85 is connected to the lower part of the fixed iron core 21, and the magnetic ring 86 is fixed to the lower part of the non-magnetic ring 85 inside the substantially cylindrical yoke 26. The inside of the magnetic ring 86 becomes a joint 90 with the extension pipe 71, and the extension pipe 71 is fixed at this portion.

The extension pipe 71 includes a hollow cylindrical pipe material 71a, which is relatively inexpensive, and a precision-machined valve body 7.
It is configured by coupling with 1b. However, in the same manner as in the above-mentioned embodiment, considering the shape change due to heat, the pipe material 7
1a and the valve body 71b are made of materials having the same coefficient of thermal expansion. The spring receiving extension shaft 51 is a rod-shaped magnetic iron core 51.
a and a non-magnetic spring receiving cylindrical rod 51b mounted so as to surround the magnetic iron core 51a in order to prevent the magnetic flux from leaking to the extension tube 71 when the magnetic flux passes through the magnetic iron core 51a. And, this spring receiving extension shaft 51
Further, the spring 61 and the plate-shaped magnetic plate 62 are integrated into one body, and are attached as shown in FIG.

The operation of the electromagnetic fuel injection valve having the above structure will be described. The fuel pressurized to a constant pressure by a fuel pump (not shown) and a pressure regulator flows from the hollow fixed iron core 21 through a gap formed in the chamfered portion of the magnetic core 81, and further passes through the inside of the extension pipe 71. The magnetic plate 62 is also supplied. When the electromagnetic coil 33 is energized by the electronic control unit (not shown) via the terminal 34 of the connector 35a, the electromagnetic coil 33 generates an electromagnetic force (in this case, an attractive force). Due to this electromagnetic force, the magnetic plate 62 rises up to a position where it collides with the lower end portion 71d of the extension pipe 71 against the biasing force of the spring 61. Then, it is held at that position by the electromagnetic force of the electromagnetic coil 33. After that, when the injection signal to the electromagnetic coil 33 is no longer output from the control device and the electromagnetic force does not act on the magnetic plate 62, the magnetic plate 62 descends due to the urging force of the spring 61 and the valve seat 71c of the valve body 71b. Abut.

Therefore, the fuel is supplied from the magnetic plate 62 and the valve seat 71c until the magnetic plate 62 rises and descends.
The fuel sprays passing through the fuel injection holes 36 through the gaps between and and further passing through the plurality of holes 17a formed in the center of the plate 17 collide with each other to be atomized and head toward the umbrella portion of the intake valve of the internal combustion engine. Further, the fuel is injected so as not to adhere to the inner wall surface of the intake manifold (not shown). Also,
In this case, the hook-like body 37 shown in FIG. 7 may be used instead of the plate 17 as the atomizing means, as in the previous embodiment.

FIG. 10 shows an example of mounting the fuel injection valve 20 (or 20b) according to the present invention on an internal combustion engine. 100 in the figure
Shows one of the cylinders of the internal combustion engine, 101 is an intake valve, 101a is its head, 102 is an exhaust valve, 103 is a cylinder, 104 is a piston, 105 is a combustion chamber, and 106 is an intake passage. As shown in this figure, the fuel injection valve 20
The fuel spray 40 injected from the tip of the extension pipe 4 (or 71) of the intake valve 101 is different from the conventional one.
It is directly supplied to the vicinity of 01a. Therefore fuel spray 4
Zero does not adhere to the wall surface of the intake passage 106. Further, the fuel spray 40 is generated by the fuel injection hole at the tip of the extension pipe 4 (or 71) and is atomized by the atomization means such as the plate 17, so that the extension pipe as in the conventional example. Fuel particles will not adhere to the inner surface of the.

11 and 12 show another example in which the atomizing means for the fuel spray 40 such as the plate 17 (see FIG. 2) is not provided at the tip of the extension pipe 4 (71). FIG.
In the example shown in FIG. 1, the umbrella portion 101a of the intake valve 101 is used as atomizing means for the fuel spray 40.
The fuel spray 40 injected from the fuel injection hole 36 opened at the tip of the extension pipe 4 (71) of 0 (20b) is the combustion chamber 10
The umbrella portion 101a of the intake valve 101 which is heated to a high temperature by receiving the heat of No. 5
Since the fuel spray 40 collides with the umbrella portion 101a to be atomized, the fuel spray 40 absorbs the heat and vaporizes a large part of the fuel spray 40, so that the fuel atomizes. Further promoted.

Further, in the example shown in FIG. 12, the fuel spray 40
As the atomizing means, a protrusion 41 that projects from the cylinder head 107 of the engine into the combustion chamber 105 and blocks the jet of the fuel spray 40 is formed. In this case, intake valve 1
When 01 is opened, when the fuel is injected from the fuel injection hole 36 at the tip of the fuel injection valve 20 (20b), the fuel spray 40
Passes through the valve opening and directly collides with the protrusion 41 in the combustion chamber 105, and since the protrusion 41 is heated to a high temperature by the combustion heat, it is atomized due to the collision and many parts are instantaneous. As a result, the fuel in the combustion chamber 105 is in a better vaporized state, and thus in a better combustion state. In either case, the fuel injection hole 36 is located near the intake valve 101
At the tip of (71), the injected fuel spray 40 collides from the closest distance toward the umbrella portion 101a and the projection portion 41, so that not only does it surely collide with the target location and do not wet the wall surface etc. Since the collision occurs before the ejection speed of the fuel spray 40 decreases, the atomization efficiency of the fuel spray 40 due to the collision increases.

[0025]

EFFECTS OF THE INVENTION The fuel injection valve of the present invention is an injection valve using an extension pipe extending to a position directly above the head portion of the intake valve.
A valve opening / closing mechanism is provided at the tip of the extension pipe, and further atomization means is provided facing the fuel injection hole so that fuel adheres to the inner surface of the extension pipe and the extension pipe does not have an air assist function. Since the atomization of the fuel flowing into the combustion chamber is promoted and the space floating ratio can be increased without the fuel dripping from the tip, the combustion can be more stabilized, and the fuel consumption and the exhaust emission can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a fuel injection valve to which the present invention is applied.

FIG. 2 is an enlarged cross-sectional view of an extension pipe tip portion of the fuel injection valve shown in FIG.

FIG. 3 is a cross-sectional view of a steel ball bonded to the tip of the needle.

FIG. 4A is a front view of a plate attached to the tip of the fuel injection valve, and FIG. 4B is a sectional view thereof.

5 is an enlarged cross-sectional view of a tip end portion of a pipe material used for the needle of the fuel injection valve shown in FIG.

6 (a) is a front view showing a modified example of the pipe material used for the needle of the fuel injection valve shown in FIG. 1, and FIG.
FIG. 7B is a sectional view taken along line BB in (a).

7 (a) is a cross-sectional view showing a modified example of the extension pipe tip portion of the fuel injection valve shown in FIG. 1, and FIG. 7 (b) shows it.
It is the figure seen from the direction.

8 (a) and (b) are the results of using a conical valve, FIG.
It is sectional drawing which compared the case where there is no needle inclination, and (c) and (d) are sectional drawings which compared the case where there is no needle inclination when using the ball valve of an Example. is there.

FIG. 9 is a sectional view of a fuel injection valve as another embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a mounting example of a fuel injection valve.

FIG. 11 is a cross-sectional view showing another mounting example of the fuel injection valve.

FIG. 12 is a cross-sectional view showing still another mounting example of the fuel injection valve.

[Explanation of symbols]

 1 ... Needle 1a ... Pipe material 1b ... Steel ball 1d ... Slit 4 ... Extension pipe 4a ... Pipe material 4b ... Valve body 4c ... Valve seat 5a ... Hole 7 ... Movable core 12 ... Orifice 13 ... Spring 17 ... Disc-shaped plate 17a ... Hole 20, 20b ... Fuel injection valve 21 ... Fixed iron core 32 ... Spool 33 ... Electromagnetic coil 34 ... Terminal 35a ... Connector 36 ... Fuel injection hole 37 ... Hook 40 ... Fuel spray 41 ... Projection 51 ... Spring receiving extension Shaft 51a ... Magnetic iron core 51b ... Spring receiving cylindrical rod 61 ... Spring 62 ... Magnetic plate 71 ... Extension pipe 71a ... Pipe material 71b ... Valve body 71c ... Valve seat 81 ... Magnetic core 100 ... Internal combustion engine 101 ... Intake valve 101a ... Umbrella part 105 ... Combustion chamber 106 ... Intake passage 107 ... Cylinder head

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02M 61/18 340 D B 69/00 310 P

Claims (5)

[Claims] 1. A fuel injection hole at a tip of a fuel injection valve is provided at a position directly above an umbrella portion of an intake valve via an extension pipe, and is configured to inject fuel spray toward the combustion chamber from that position. In addition, an opening / closing mechanism of a valve that opens and closes the fuel injection hole is provided at the tip of the extension pipe, and injection and cutoff of fuel are controlled at the tip of the extension pipe. Fuel supply system. 2. The fuel supply device for an internal combustion engine according to claim 1, wherein the atomizing means for fuel spray is provided at the tip of the extension pipe so as to face the fuel injection hole. 3. The fuel for an internal combustion engine according to claim 1, wherein materials having the same coefficient of thermal expansion are selected and used as materials of parts forming the opening / closing mechanism of the valve including the extension pipe and the needle. Supply device. 4. The valve opening / closing mechanism is configured by a spherical valve element attached to the tip of a needle and the fuel injection hole, according to any one of claims 1 to 3. Fuel supply device for internal combustion engine. 5. The valve opening / closing mechanism includes a magnetic plate for opening / closing the fuel injection hole by an electromagnetic force at a tip portion of the extension pipe, according to any one of claims 1 to 3. Fuel supply device for internal combustion engine.