JPS61272460A - Electromagnetic type fuel injection valve - Google Patents

Abstract

PURPOSE:To reduce the formation of vapor and permit the superior injection by setting the ratio between the sum of the flow passage areas of two holes as the branched flow passages of a branched-flow member and the flow passage area of an injection hole into the range of a specific value. CONSTITUTION:A branched-stream member 8 onto which the flow passages for allowing the flow of fuel jetted from an injection hole 62 to branch-flow are formed is installed at the edge part of a body 6. The flow passage of the branched-flow member 8 is formed at the position corresponding to the injection hole 62, and the inlet for the fuel flow supplied from the injection hole 62 is formed in the form in which each part of two circles are superposed each other. The flow passage is branched as two holes 81 having each certain diameter, in a prescribed angle from the inlet in the branched-flow member 8, and opened at two positions at the edge part for the outer space. When the flow passage area of the injection hole is set S1, and the sum of the flow passage areas of two holes as the flow passages of the branched-flow member is set S2, the following relation between the surface areas S2/S1 is satisfied: 6<=S2/S1<=8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic fuel injection valve that mainly injects and supplies fuel to a four-valve automobile engine having two intake valves per cylinder. It is.

[Conventional technology]

Conventionally known electromagnetic fuel injection valves have an internal electromagnetic coil, and by supplying an electric signal to this electromagnetic coil, a valve body such as a needle valve is actuated, and fuel is injected into the engine from the injection hole. It was something. Such a fuel injection valve can realize optimal fuel supply corresponding to the operating state of the engine by controlling an electric signal to the electromagnetic coil by an engine control unit.

Incidentally, in recent years, attempts have been made to provide two intake valves in each cylinder of an engine to reduce intake resistance especially at high speed rotation and to maintain high engine output. In such an engine, the intake pipe branches into a plurality of pipes corresponding to each cylinder, and further branches into two directions corresponding to each intake valve, and usually, the fuel injection valve branches into two directions corresponding to each cylinder. It is installed upstream of the section.

However, when a conventional fuel injector, which only injects fuel in one direction, is installed in the above position, fuel adheres to the wall of the intake pipe in the middle, resulting in poor mixing of air and fuel, which affects the transient characteristics of the engine. This caused delays.

In order to prevent fuel from adhering to the wall surface of the intake pipe in the middle, and to improve the transient characteristics of the engine, the electromagnetic type is configured to split the fuel injection direction into two directions toward the intake valve. The fuel injector is made by Nippondenso, serial number 33-0.
65.

[Problem that the invention seeks to solve]

Conventionally, fuel leakage occurs when the inside of the intake pipe to which the fuel injection valve is attached is exposed to negative pressure, such as when the engine is idling or decelerating, or when there is a dead soak such as when restarting after high-speed operation. When the injection valve or fuel is exposed to high temperatures, paper tends to form in the fuel. And in the fuel injection valve shown in the public branch axis above,
The fuel flow injected from the injection hole to the downstream side of the injection hole is
It is equipped with a plate (flow diversion member) in which a hole is formed to divide the flow in the direction, and the valve body is equipped with a plate (flow diversion member) in which the flow is divided into two directions.
Many step-shaped parts are formed in the fuel flow path to the hole portion, which obstructs the smooth flow of the fuel flow, and even if the two holes have a passage area that does not restrict the flow rate of the fuel flow, the smooth flow of the fuel can be prevented. As a result, the generation of paper is promoted in that area, and as described above, under negative pressure or high temperature conditions, paper is generated, and the amount of fuel injected from the fuel injection valve is reduced to the desired amount. There is a problem in that the amount decreases further, making it impossible to measure with high precision.

Therefore, an object of the present invention is to allow the fuel flow from the injection hole to smoothly flow into the two holes of the flow dividing member, to minimize the factors that promote paper generation, and to reduce the amount of fuel under negative pressure and high temperature conditions. It is an object of the present invention to provide an electromagnetic fuel injection valve that is capable of metering with sufficiently high accuracy even in the case of the present invention.

[Means to “solve” the problem]

In order to solve the above problems, in the present invention, an electromagnetic coil is provided inside a housing, and an electromagnetic coil is slidably disposed within a body connected to the housing.
A needle valve that fluctuates by supplying an electric signal to an electromagnetic coil, an injection hole that is formed at the end of the body and injects fuel in response to fluctuations in the needle valve, and an end of the body where the injection hole is formed. The flow path of the flow dividing member is formed at a position corresponding to the injection hole, and the flow path of the flow dividing member is formed at a position corresponding to the injection hole. The inlet of the fuel flow from the inlet opens in the shape of two circles partially overlapping each other, and the center of the outlet of the injection hole corresponds to the center of the part of the two circles of this inlet partially overlapping each other. , this inlet corresponds to the outlet of the injection hole and has a size that can accommodate the opening range of the outlet of the injection hole, and two holes each having a constant diameter are formed at a predetermined angle from this inlet in the flow dividing member. It is branched and opens to the external space at two places at the end, and the flow path area of the injection hole is S1, and the sum of the flow path areas of the two branched holes, which are the flow paths of the flow dividing member, is 82. In this case, the area ratio S2/S+ satisfies the following: 6≦Sz/S+≦8.

[For production]

According to the above configuration, the fuel flow flowing from the injection hole into the flow path of the flow dividing member flows smoothly because the inlet of the flow path reliably covers the outlet of the injection hole. In addition, since the ratio of the flow path area of the injection hole to the sum of the flow path area of the flow path of the flow dividing member is between the above values, the flow is not restricted, and even better spraying is achieved through the flow dividing member. It is injected from two outlet side openings.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, a housing 1 of an electromagnetic fuel injection valve 100 has a stepped cylindrical shape, and an electromagnetic coil 3 is arranged around a spool 2 in a large diameter portion of the housing 1. A cylindrical iron core 4 extends through the spool 2 from above.
The upper end serves as a connection part for a fuel supply pipe, and the flange part protruding from the cylinder wall is caulked and fixed to the upper opening edge of the △Uji puffer 1. A filter 41 is disposed at the upper opening of the iron core 4, and an adjustment pipe 42 forming a fuel flow path is fixed inside the cylinder. A power supply connector 5 is integrally molded with resin on the top surface of the housing 1.
The electromagnetic coil 3 is connected to a connector pin 51.

A body 6 is caulked and fixed to the small diameter portion of the housing l via a spacer 61, and an injection hole 62 is formed in the end surface of the body 6 that projects downward. A needle valve 7 is slidably inserted into the body 6 from above, and the tip of the needle valve 7 is formed into a conical shape. A stopper 71 is formed. A movable core 72 is connected to the upper end of the needle valve 7 facing the iron core 4, and the movable core 72 is connected to a coil spring 73 disposed between the movable core 72 and the adjustment pipe 42.
is urged downward by.

A flow dividing member 8 is press-fitted into the end of the body 6 where the injection hole 62 is formed, and the flow dividing member 8 divides the fuel flow from the injection hole 62 into a predetermined 2 points corresponding to the injection hole 62. Two holes 81 are formed to separate the flow in the direction.

When an electric signal is supplied to the electromagnetic coil 3 of the fuel injection valve 100, the movable core 72 is attracted toward the iron core 4 against the spring force, and as a result, the needle valve 7 is moved until the space 61 and the stopper 71 come into contact with each other. The fuel that has moved upward and reached the outer periphery of the needle valve 7 from the adjustment pipe 42 via the movable core 72 is injected from the injection hole 62 and is
The two holes 81 separate the flow.

FIG. 2 shows an enlarged sectional view of the injection hole 62 portion.

The injection holes 62 of the body 6 are formed with high precision, and the fuel passing through the body 6 is narrowed down to a predetermined amount by the injection holes 62. As shown in FIG. Parts of the circles overlap each other.The center of the outlet of the injection hole 62 and the part of the circle at the entrance to the two holes 81 overlap each other, that is, the fuel flow is split into two directions. The two holes 81 are arranged so as to substantially coincide with the center of the tip of the partition wall 83, and from the entrance portion to the two holes 81, the two holes 81 are formed with the injection hole 62 as the center line and are opened by an angle θ. The two holes 81 are branched within the flow dividing member 8, and the exits of the two holes 81 each open into the external space in a circular shape.The diameter of the holes 81 is not constant. Both have the same diameter d, which is larger than the diameter of the injection hole 62.

Furthermore, the length of the overlapping portion on the inlet side of the two holes 81 is longer than the diameter of the injection hole 62.

This is to prevent the fuel flow from the injection hole 62 from colliding with the inlet side end 84 of the flow dividing member 8, so that the fuel flow from the injection hole 62 is directed toward the inlet side of the two holes 81. becomes extremely smooth. For example, when the center distance of each diameter 81 on the inlet side is set to X, the length P of the overlapping portion is, and the length P of this overlapping portion is larger than the diameter of the injection hole 62. In other words, the condition D≦dt-)(!) is satisfied.

Further, the flow path area S1 of the injection hole 62 and the sum S2 of the flow path area of the two holes 81 of the flow dividing member 8 satisfy the following relationship.

6≦St/St≦8 In other words, 6≦2・(d/D>”≦8 This means that according to the experiments conducted by the present inventors, as shown in FIG. 4, the channel area ratio S!/Sl is 6 If it is less than twice that, under negative pressure or high temperature, the fuel metered by the injection hole 62 is squeezed by the two diameters 81, which tends to generate paper, which causes pressure loss and lowers the flow rate than the desired flow rate. However, if it is 6 times or more, the generation of paper can be suppressed,
In addition, even if it occurs, there is a sufficient flow path, so the pressure loss is small, so it will not drop, and if it is made 8 times or more, it will be too wide, causing turbulence in the spray from the exits of the two holes 81, and reducing the particle size. This is because it has been confirmed that substantially good spraying can be obtained at 8 times or more, although it becomes coarser.

By satisfying each of the above conditions, the fuel injected from the spray holes 62 smoothly flows into the two holes 81 of the flow dividing member 8 without colliding with the inlet side end surface 84 at the inlets of the two holes 81. Since the flow path area of the injection hole 6"2 is sufficiently large compared to the flow path area of the injection hole 6"2, the generation of paper can be suppressed, and even if paper is generated in the area of the two holes 81, the flow path area of the hole 81
Since the flow path area of S is sufficiently larger than the flow path area of the injection hole 62, pressure loss is small, and metering with high precision is possible even under negative pressure or high temperature conditions, and the area ratio S! / S l
By making the amount 8 times or less, good atomization can also be obtained.

Furthermore, the following conditions may be added in addition to the above conditions.

(1) When the length of the hole 81 is L, its slenderness ratio L
/d is 1≦L/d≦2.

(2) If the distance of the gap 82 is M, then 0.2 m
+*≦M≦1. Onum.

According to the experiments conducted by the present inventors, the condition (1) is such that the two holes 81 are widened so that the spreading angle of the fuel flow injected from the two holes 81 is θ, as shown in FIG. While the angle is set to θ, if the slenderness ratio L/d<l, the fuel flow injected from the two holes 81 will have an angle smaller than θ, but if L/d≧1 Set spread angle θ
In addition, if L/d>2, under negative pressure or high temperature conditions, paper is likely to be generated inside the hole 81 because it is too long for the diameter, and paper generation causes pressure loss and two pieces. Although the flow rate of fuel from the hole 81 of L decreases,
This is because if /d≦2, it is confirmed that there is almost no decrease in the fuel flow rate.

According to the experiments conducted by the present inventors, the condition (2) is as shown in FIG. 6. When M<0.2m+n, the outlet of the injection hole 62 and the two holes 81 Since the distance to the partition wall 83 that branches the fuel in two directions is too close, paper is likely to be generated in this area, and the paper generation causes pressure loss, and the flow rate of fuel from the two holes 81 is - However, by setting M≧0.2mm, there is almost no decrease in the fuel flow rate (and approximately M > 1
It has been confirmed that if the volume from the seat surface of the 21-dollar valve 7 to the outlet of the two holes 81, that is, the dead volume, increases, fuel drips from the tips of the two holes 81. Because there is.

Note that in the above configuration, the diameters of the two holes 81 are the same, but they may have different diameters, but it is not preferable to drastically change the sizes.

〔Effect of the invention〕

As described above, according to the present invention, the electromagnetic coil is provided inside the housing, and the electromagnetic coil is slidably disposed within the body connected to the housing, and supplies an electric signal to the electromagnetic coil. A needle valve that fluctuates depending on the movement of the needle valve, an injection hole that is formed at the end of the body and injects fuel according to the fluctuation of the needle valve, and an injection hole that is provided at the end of the body where the injection hole is formed and that injects fuel from the injection hole. The flow path of this flow dividing member is formed at a position corresponding to the injection hole, and the inlet of the fuel flow from the injection hole is formed in two directions. The openings are formed in such a way that parts of the circles overlap each other, and the exit center of the injection hole is located at the two entrances.
This inlet corresponds to the center of the part where some of the circles overlap each other, and this inlet corresponds to the outlet of the injection hole, and is large enough to accommodate the opening range of the outlet of the injection hole, and is located at a predetermined angle from this inlet. The flow path area of the injection hole is Sl, and the flow path of the flow path of the flow dividing member is divided into two holes with a constant diameter. When the sum of the flow path areas of two branched holes is 82, the area ratio St/St is 6≦32/St≦8. , factors that promote paper formation in the fuel flow between the injection hole and the outlet of the two holes in the flow dividing member are sufficiently suppressed, and pressure loss under negative pressure and high temperature conditions is reduced. Therefore, metering can be achieved with sufficient precision, and by maintaining the area ratio as described above, good spraying can be achieved.
It has the excellent effect of being sprayed from several holes.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the electromagnetic fuel injection valve of the present invention, FIG. 2 is a partial sectional view of the electromagnetic fuel injection valve shown in FIG. The figure showing the inlet side of the two holes in the cross section, and FIGS. 4 to 6 are graphs showing the experimental results of the present inventors. DESCRIPTION OF SYMBOLS 1... Housing, 3... Electromagnetic coil, 6... Body, 7... Needle valve, 8... Diversion member, 62...
...Injection hole, 81...hole, 82...gap, 84...
・Inlet side end face, 1°O...Electromagnetic fuel injection valve. Representative Patent Attorney Takashi Okabe Figure 1

Claims (1)

[Claims] (1) An electromagnetic coil provided inside a housing and a body connected to the housing so as to be slidable and fluctuate by supplying an electric signal to the electromagnetic coil. A needle valve, an injection hole that is formed at the end of the body and injects fuel according to fluctuations in the needle valve, and a fuel flow injected from the injection hole that is provided at the end of the body where the injection hole is formed. The flow path of this flow dividing member is formed at a position corresponding to the injection hole, and the inlet of the fuel flow from the injection hole is located at one of the two circles. The exit center of the injection hole corresponds to the center of the part where the two circles of this inlet overlap each other, and the injection hole is opened at the part corresponding to the exit of the injection hole. The size is large enough to accommodate the opening range of the hole exit, and two holes of a constant diameter are formed at a predetermined angle from the entrance.
The holes are branched within the flow dividing member and open to the external space at two locations at the ends, making the flow path area of the injection hole S_
1. An electromagnetic device characterized in that, when the sum of the flow path areas of two branched holes, which are flow paths of the flow dividing member, is S_2, the area ratio S_2/S_1 is 6≦S_2/S_1≦8. type fuel injection valve. (2) The electromagnetic fuel injection valve according to claim 1, wherein the flow path of the flow dividing member is constituted by a combination of two holes having the same diameter. (3) A patent characterized in that when the diameter of the hole forming the flow path of the flow dividing member is d and the length of the hole is L, the slenderness ratio L/d is 1≦L/d≦2. An electromagnetic fuel injection valve according to claim 1 or 2. (4) A gap is formed between the outlet side of the injection hole and the flow path inlet of the flow dividing member, and the distance of this gap is M
The electromagnetic fuel injection valve according to claim 1, 2, or 3, wherein: 0.2 mm≦M≦1.0 mm.