JPH08200187A - Fuel injection valve - Google Patents

Abstract

PURPOSE: To provide a fuel injection valve to reduce the spread of fuel spray and to increase a fuel injection amount. CONSTITUTION: A disc 20 is welded to the outer wall of the tip of a nozzle body containing a needle valve, and fuel flowing in through a fuel pass hole formed in the nozzle body is injected in two directions through two injection nozzles 20a. The injection nozzle 20a is extended through the disc 20 and the two injection nozzles are formed in parallel in the disc 20. The shape in cross section of the flow passage of the injection nozzle 20a is straight and elongated and both ends are formed in an arcuate shape. By shortening the length a1 of the injection nozzle 20a, the angle on the spray side of fuel is reduced and by reducing the width (b) of the injection nozzle 20a, fuel spray is atomized. Since fuel is injected through the injection nozzle 20a of which a continuous flow passage consists, much quantities of fuel is injected at a reduced angle on the spray side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, a fuel injection type internal combustion engine (hereinafter, referred to as
In the "engine", fuel injection valves are installed in the intake passages connected to the respective cylinders, and fuel is supplied from the fuel injection valves to the respective cylinders. Generally, the combustion efficiency of a fuel injection type engine is affected by the air-fuel ratio and the size of particles of fuel injected from a fuel injection valve.
In order to increase the combustion efficiency, it is effective to atomize the fuel injected from the fuel injection valve and supply the atomized fuel. This is because when the fuel is atomized and injected, it is quickly ignited and the combustion is completed in a short time, so that the combustion efficiency is increased. Increasing the combustion efficiency reduces the exhaust gas, particularly the exhaust concentration of hydrocarbons HC. In recent years, particularly in automobiles, the exhaust gas regulations of automobiles have been tightened along with the heightened awareness of environmental protection, and therefore it is necessary to atomize the fuel injected from the fuel injection valve to improve the fuel efficiency.

In order to atomize the fuel injected from the fuel injection valve, the fuel injection pressure is increased, the number of injection holes and the direction of the injection holes are modified, and the fuel injected from the fuel injection valve is changed. Various means such as blowing air have been considered.
Since the cost of the means for blowing air to the fuel injected from the fuel injection valve is high, recently, the number of injection holes is increased and the diameter of the injection holes is reduced to the mainstream. If the fuel injection amount is the same, increasing the number of injection holes can reduce the injection hole diameter, which is advantageous for atomizing the fuel, but it is disadvantageous for spraying from the engine and clogging of injection holes due to poor fuel. is there. Therefore, the plate type with four injection holes is the mainstream. In particular, in order to deal with a high-performance engine having two intake valves, a two-way injection type in which fuel injected from a fuel injection valve is divided into two directions and injected is well known. As such a fuel injection valve, the one disclosed in Japanese Utility Model Laid-Open No. 2-1463 is known.

FIG. 9 shows a conventional two-way injection fuel injection valve in which a plate is provided with four injection holes, and two injection holes are paired to form one fuel spray. In this case, the pitch p of the injection holes 70a formed in the plate 70,
The diameter d ₁ of the injection hole 70a greatly affects the spray shape of the fuel injected from the fuel injection valve and the particle size of the fuel spray. For example, as shown in FIG. 10, the injection hole diameter d of the injection hole 70b
_The smaller the value of ₂ , the smaller the particle size of the fuel spray. Also,
In order to cope with an engine having a large displacement, it is necessary to increase the amount of fuel injected from the fuel injection valve, and as shown in FIG. 11, increasing the injection hole diameter d ₃ of the injection hole 70c increases the fuel injection amount. be able to.

[0005]

However, in the conventional two-way injection fuel injection valve shown in FIG. 9, the portion of the pitch p between the injection holes shown in FIG. 9A is a portion where fuel cannot be injected. The spray width at the spray start position is widened by this pitch p, and the spray side angle θ shown in FIG. 9C is widened. The spray side angle θ here is an angle formed between the spray center O of the plate 70 and both ends of the fuel spray width at a position separated from the spray center O in the spray shape of the fuel in each injection direction. means. Comparing the spray side angle of the fuel spray at a position separated from the spray center O by the same distance, the spread of the fuel spray increases as the spray side angle increases. Further, when the injection hole diameter d (subscripts are omitted) is determined by the amount of fuel required by the engine, the dimension e is restricted by the following equation (1) in view of the injection hole processing. The pitch p is set to a length equal to or larger than the injection hole diameter d.

E = 2d + p ≧ 3d (1) Therefore, as shown in FIG. 11, when the injection hole diameter d ₃ is increased to increase the fuel injection amount, the injection hole diameter d ₃ becomes Since it is necessary to set the pitch p of the injection holes to the same extent, the e dimension becomes long and the spray width at the spray start position widens, so the spray side angle becomes large. Since the intake pipe of recent high-performance engines has a narrow intake passage, atomized fuel adheres to the inner wall of the intake pipe and enters the cylinder when the side angle of fuel spray increases. That is, even if the particle size of the fuel spray is made small, if the spray side angle of the fuel becomes large, the fuel having a large particle size will enter the cylinder with a delay, resulting in a decrease in combustion efficiency and, as a result, carbonization in the exhaust gas. The concentration of hydrogen HC will increase.
As described above, in an engine with a large displacement, it is difficult to achieve both atomization of the fuel injected from the fuel injection valve and reduction of the spray side angle.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a fuel injection valve in which the spread of fuel spray is small and the fuel injection amount can be increased.

[0008]

A fuel injection valve according to claim 1 of the present invention for solving the above-mentioned problems is a fuel injection valve for an engine having a plurality of injection holes at its tip end, wherein The injection hole is characterized in that the cross-sectional flow path is formed in an elongated shape, and the axes of the plurality of injection holes intersect on the side opposite to the fuel injection direction.

A fuel injection valve according to a second aspect of the present invention is the fuel injection valve according to the first aspect, wherein a valve body having a fuel through hole at a tip thereof and a sliding hole formed in the valve body in an axial direction. And a needle valve capable of opening and closing the fuel passage, the injection hole being formed in a plate provided on the fuel injection downstream side of the fuel passage, The feature is that fuel flows into the injection holes.

A fuel injection valve according to a third aspect of the present invention is the fuel injection valve according to the second aspect, wherein the needle valve is biased in one direction and the biasing means is activated by energizing the needle valve. And a solenoid capable of moving the needle valve in the opposite direction to the biasing means.

[0011]

According to the fuel injection valve of the first aspect of the present invention, the cross-sectional flow passages of the plurality of injection holes are formed in an elongated shape, and the axis of the injection holes is opposite to the fuel injection direction. By intersecting with each other, the spread of the fuel spray can be made small and the fuel injection amount can be made large. For example, the two-way injection suitable for a high-performance engine having two intake valves is possible.

According to the fuel injection valve of the second aspect of the present invention, by forming the injection hole in the plate provided on the fuel downstream side of the valve body, for example, when the required amount of the fuel injection amount differs for each engine, The fuel injection amount can be easily adjusted without changing the other parts by simply selecting the plate having the injection holes corresponding to the required amount. Claim 3 of the present invention
According to the fuel injection valve described above, the injection timing control of the fuel injection valve can be performed with high accuracy by moving the needle valve with the current supplied to the solenoid.

[0013]

An embodiment of the present invention will be described with reference to the drawings.
An embodiment of the fuel injection valve according to the present invention is shown in FIGS. As shown in FIG. 4, the fuel injection valve 1 of the present invention is installed in a fuel distribution pipe 60 and injects fuel toward an intake valve 62 that opens and closes an intake port of a combustion chamber. Two intake valves 62 are provided for each cylinder, and the other intake valve is not shown in FIG. 4 because it overlaps the illustrated intake valve 62. The injected fuel is sent to the combustion chamber at the opening timing of the intake valve 62 together with the air taken into the intake pipe 61. Since the fuel injection valve 1 is installed inside the fuel distribution pipe 60, the rubber O-rings 51 and 52 that prevent fuel from leaking from the distribution pipe 60 to the outside are provided in the nozzle body 11.
And the outer peripheral wall of the housing 2 are fitted together.

As shown in FIG. 2, the fuel injection valve 1 is a bottom field type electromagnetic fuel injection valve and comprises a valve portion 10 and an actuator portion 30. The housing 2 is made of magnetic metal, and caulks and fixes the nozzle body 11 of the valve portion 10 and the fixed core 31 of the actuator portion 30. The needle valve 12 is accommodated in a sliding hole 11a formed in the inner wall of the nozzle body 11 so as to be capable of reciprocating. The plate 20 is welded to the outer wall of the tip of the nozzle body 11. Tip of nozzle body 11 and plate 2
A cap 21 is fitted to the outer peripheral wall of the nozzle body 11 so as to cover 0. The cap 21 is for preventing the O-ring 51 from falling off.

As shown in FIG. 3, a fuel through hole 11b is formed at the tip of the nozzle body 11. Needle valve 1
The seat portion 12a formed at the front end portion of the fuel cell 2
When seated on the valve seat 11c formed on the fuel upstream side of b, the fuel flow to the fuel passage hole 11b is shut off, and the seat portion 12a
When is separated from the valve seat 11c, the fuel flows into the fuel passage hole 11b. The fuel ejected from the fuel through hole 11b is the plate 2
When it passes through the injection hole 20a formed in 0, it is atomized and injected from the fuel passage hole 21a of the cap 21 toward the intake valve 62.

As shown in FIG. 1A, the injection hole 20a is
Through the plate 20, two parallel plates are formed.
Have been. The injection hole 20a has a straight cross-section with a straight passage shape.
It has a long shape and both ends are formed in an arc shape. Of FIG.
As shown in (B), the fuel is burned in two directions from the two injection holes 20a.
The charges are being sprayed. The plate thickness c of the plate 20 is 0.1
~ 1 mm. Length a of injection hole 20a₁Sucks the engine
Depending on the shape of the intake passage in the trachea, within approximately 1 mm
Is set to. The width b of the injection hole 20a depends on the engine demand.
Fuel amount and the length of the injection hole 20a set for the above reason
a₁It depends on the setting, but it is set within 0.1-0.3mm.
Have been. Is it the engine that does not make it smaller than 0.1 mm?
To prevent clogging of nozzle holes due to spraying of fuel and poor fuel
Is. Such a length a of the injection hole 20a₁And of width b
Within the formation range, the length a of the injection hole 20a₁ To shorten
The side angle of fuel spray can be made smaller, and the width b of the injection hole 20a can be reduced.
By making it small, the fuel spray is atomized. Of FIG.
As shown in (B), the injection hole 20a is
It is formed so that the axes intersect on the opposite side,
This gives a bidirectional spray profile. This tilt angle
x is determined by the shape of the intake passage of the intake pipe,
It is 10 ° to 45 °.

As shown in FIG. 2, the fuel passage 2a is formed in the side wall of the housing 2, and the fuel from which foreign substances have been removed by the fuel filter 22 attached to the outer wall of the housing 2 slides from the fuel passage 2a. It flows into the hole 11a. The actuator unit 30 includes a movable core 32 connected to the head 12b of the needle valve 12, a fixed core 31 caulked and fixed to the housing 2, and a fixed core 3 wound around a bobbin 33.
1 and a coil 34 installed on the outer circumference of the coil 1. A compression coil spring 35 that urges the movable core 32 toward the valve closing direction of the needle valve 12 is interposed between the movable core 32 and the fixed core 31. A through hole 37 communicating with the outside is formed in the fixed core 31, and the through hole 37 is formed.
An adjusting pipe 36 for adjusting the urging force of the compression coil spring 35 is inserted and fixed in. The rubber O-ring 38 is provided on the outer wall of the adjust pipe 36 and the fixed core 31.
The inner walls of the above are sealed to prevent the fuel from leaking to the outside from the through hole 37.

A power receiving pin 41 is attached to the bobbin 33, and the base end of the power receiving pin 41 is connected to the coil 34. The tip of the power receiving pin 41 is exposed inside the connector 40 made of an electrical insulator such as synthetic resin. When a current is supplied to the power receiving pin 41 from a power source (not shown), a current is supplied to the coil 34, an electromagnetic force is generated in the coil 34, and the movable core 32 is attracted to the fixed core 31 side against the biasing force of the compression spring coil 35. To do.

Next, the operation of the fuel injection valve 1 will be described. (1) When current is supplied from the power receiving pin 41 to the coil 34, the movable core 32 is attracted to the fixed core 31 against the biasing force of the compression coil spring 35 by the generated magnetic force. When the needle valve 12 is lifted together with the movable core 32, the seat portion 12a is separated from the valve seat 11c, so that the fuel flows into the fuel passage hole 11b. When the fuel flowing into the fuel through hole 11b passes through the injection hole 20a of the plate 20, it forms a predetermined spray side angle as shown in FIG. 1 (c), and is injected in two directions through the fuel through hole 21a. To be done. In the present embodiment, the fuel is injected in one direction of the two-way injection through the single injection hole 20a having the elongated cross-sectional flow path shape, so that the two-direction injection is performed by the two injection holes. As compared with a fuel injection valve that injects fuel in one direction, there is no wasteful portion between the injection holes. Therefore, the fuel can be injected from the injection hole 20a that forms one continuous flow path, so that a large amount of fuel can be injected with a small spray side angle.

(2) When the current supply to the coil 34 is cut off, the needle valve 12 is lowered by the urging force of the compression coil spring 35, and when the seat portion 12a is seated on the valve seat 11c, the fuel passage hole 11b is cut off. , Fuel injection ends. In the present embodiment, the flow path shape of the cross section is formed in an elongated shape,
The fuel was injected from the injection holes 20a having arcuate ends, but a modification of the injection hole shape will be described below.

(Modification 1) FIG. 5 shows a modification 1 of this embodiment. The plate 25 of the modification 1 has three holes 25 b whose cross-sectional flow path shape is circular and is formed by superimposing three holes 25 b on a straight line.
a. The diameter d of the holes 25b is larger than the pitch p ₁ between the centers of the holes 25b. In the modified example 1,
Since the flow passage area of the injection hole 25a can be easily adjusted by adjusting the pitch p ₁ , the fuel injection amount can be finely adjusted.

(Modification 2 and Modification 3) FIG. 6 shows a plate 26 of a modification 2 of this embodiment, and FIG. 7 shows a plate 27 of a modification 3. In the modified examples 2 and 3, the injection holes 26a,
The cross-sectional flow path shape of 27a is formed in an elongated arc shape. Therefore, when the fuel injection amount is the same, the injection hole length a ₂ becomes shorter than the injection hole length a ₁ of the first embodiment, so that the fuel spray side angle can be made smaller.

(Modification 4) FIG. 8 shows a plate 28 of Modification 4 of the present embodiment. Modification 4 is one in which the injection hole 28a is formed in a slit shape. In the embodiments of the present invention described above, various shapes of the injection holes are shown, but the shapes of the injection holes are not limited to these in the present invention, and the flow passage shape of the cross section is formed in an elongated shape. Any shape is possible.

[Brief description of drawings]

FIG. 1 is a plate of a fuel injection valve according to an embodiment of the present invention, (A) is a plan view, (B) is a view in the direction of arrow B of (A), and (C) is (A). ) Is a C direction arrow view of FIG.

FIG. 2 is a sectional view showing a fuel injection valve according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a tip portion of a fuel injection valve of this embodiment.

FIG. 4 is a cross-sectional view showing a state where the fuel injection valve of the present embodiment is attached to a fuel distribution pipe.

FIG. 5 is a plan view showing a plate according to a modified example 1 of the present embodiment.

FIG. 6 is a plan view showing a plate according to a modified example 2 of the present embodiment.

FIG. 7 is a plan view showing a plate according to a modified example 3 of the present embodiment.

FIG. 8 is a plan view showing a plate according to a modified example 4 of the present embodiment.

9A and 9B show a plate of a conventional example, FIG. 9A is a plan view, and FIG. 9B is a view in the direction B of FIG.
(C) is a C direction arrow view of (A).

10 shows the plate shown in FIG. 9 with a smaller injection hole diameter, (A) is a plan view, and (B) is B of (A).
It is a direction arrow view.

FIG. 11 shows the plate shown in FIG. 9 with a larger injection hole diameter, (A) is a plan view, and (B) is B of (A).
It is a direction arrow view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel injection valve 11 Nozzle body (valve body) 12 Needle valve 20, 25, 26, 27, 28 Plate 20a, 25a, 26a, 27a, 28a Injection hole 34 Coil (solenoid) 35 Compression coil spring (biasing means)

Claims (3)

[Claims] 1. A fuel injection valve for an internal combustion engine having a plurality of injection holes at a tip end thereof, wherein the plurality of injection holes are formed such that a flow passage shape of a transverse cross section is elongated, and a shaft of the plurality of injection holes is formed. Is a fuel injection valve characterized by intersecting with the fuel injection direction on the opposite side. 2. A valve body having a fuel passage hole at its tip, and a needle valve which is accommodated in a sliding hole formed in the valve body so as to be capable of reciprocating in the axial direction and which can open and close the fuel passage hole. The fuel injection valve according to claim 1, wherein the injection hole is formed in a plate provided on the fuel injection downstream side of the fuel communication hole, and the fuel flows from the fuel communication hole into the injection hole. 3. A biasing means for biasing the needle valve in one direction, and a solenoid capable of moving the needle valve in a direction opposite to the biasing means against the biasing means by energizing. The fuel injection valve according to claim 2, further comprising: