JPS62131969A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To reduce the generation of vapor even under negative pressure or high temperature by making the sum of the sectional areas of two injected flow passages sufficiently larger than the area of a fuel flow passage in a gap part of an injection port toward a pintle. CONSTITUTION:In an electromagnetic fuel injection valve 100, a pintle housing part 81 for housing the end of a pintle which is projected out from an injection port 62, and two injected flow passages 82 which connect the pintle housing part to an outer space while which branch a jet injected form the injection port 62 in two directions, are formed opposite to the injection port 62, in a sleeve 8 which is set on the outside end part of a body 6. In this case, the ratio of the diameter of the pintle housing part 81 to the diameter of the injection port 62 is set 3 or more. Also, the sum of the sectional areas of the two injected flow passages 82 is made sufficiently larger than the area of a fuel flow passage of the gap part of the injection port 62 toward the pintle 71. Thereby, the flows of jet at the pintle housing part 81 and the injected flow passage 82 can be made smooth, reducing a principal cause for promoting the generation of vapor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention mainly relates to an electromagnetically operated fuel injection valve for injecting and supplying fuel to an automobile engine having two intake valves per cylinder. It is related to.

[Conventional technology]

Conventionally known electromagnetically operated 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 through the injection hole. It was supplied by injection. 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.

By the way, in recent years, many automobile engines have been equipped with two intake valves in each cylinder of the engine, which reduces intake resistance especially at high speeds and makes it possible to maintain high engine output. has been done. In such an engine, the intake pipe branches into two directions corresponding to each cylinder, and the fuel injection valve is usually installed at a position upstream of the part where the intake pipe branches into two directions corresponding to each cylinder.

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 air-fuel mixing (and transient characteristics of the engine). This caused delays.

In order to prevent fuel from adhering to the wall 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. Various fuel injection valves have been proposed.

For example, Nippondenso Publication Technical Report No. 31-223 discloses a device in which an adapter is provided to achieve a desired direction of fuel injection from the injection hole.

[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 above technical report,
An adapter is set on the downstream side of the injection hole to direct the injection direction of the fuel injected from the injection hole to the desired direction, but simply setting up such an adapter will cause the fuel to be injected from the injection hole. In order to change the flow of fuel in the desired direction, the smooth flow of fuel is obstructed, and paper formation is promoted in that area. There is a problem in that paper is generated and the amount of fuel injected from the fuel injection valve is reduced from the desired amount, making highly accurate metering impossible.

Therefore, an object of the present invention is to atomize a jet of fuel from an injection hole by a pintle in a pintle storage part, and to inject this atomized jet of fuel into an external space through each jet path. The shape of the pintle storage part and each jet flow path is set so that the flow of the jet flow is sufficiently smooth in the flow path up to the flow path, and the factors that promote paper generation in this pintle storage part and each jet flow path are set. It is an object of the present invention to provide a fuel injection valve which is capable of metering with sufficiently high accuracy even under negative pressure and high temperature conditions by minimizing the amount of fuel.

[Means for solving problems]

In order to solve the above problems, the present invention includes: a needle valve disposed in a movable state along a sliding space formed inside a body; a needle valve formed at one end of the body; an injection hole that is opened and closed by a valve and injects fuel when the valve is opened; and an injection hole that is formed at the tip of the needle valve and protrudes through the injection hole through a small gap with the injection hole, and that is configured to prevent movement of the needle valve. a pintle that moves within the injection hole in accordance with the injection hole and is provided with an atomization means for atomizing the fuel injected from the injection hole at its tip; and a tip of the pintle that protrudes from the injection hole. Store and
A pintle storage section consisting of a cylindrical space portion having a diameter sufficiently larger than the passage diameter of the injection hole, and the pintle storage section is communicated with an external space, so that the jet flow injected from the injection hole is divided into two directions. Two jet flow passages are formed corresponding to the injection holes and include a sleeve set at an outer end of the body, a diameter D+ of the pintle storage portion and a passage diameter D of the injection hole.
The ratio DI/DZ with t is DI/D! ≧ 3, and the sum S2 of each flow passage cross-sectional area of the two jet flow passages is larger than the fuel flow passage area S1 of the gap between the injection hole and the pintle.
The fuel injection valve is characterized by being sufficiently large.

[Effect]

With the above configuration, the flow of the jet is not restricted in the flow path from the injection hole to the external space (and is smoothly ejected to the external space via the pintle storage part and each jet flow path). .

〔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 10. 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 cylindrical wall is caulked and fixed to the upper opening edge of the housing 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 from resin on the upper surface of the housing 1, and 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 1 via a spacer 61, and an injection hole 62 is formed in the end surface of the body 6 that projects downward. A sliding space 63 in which the needle valve 7 slides is formed in the body 6, and the needle valve 7 is slidably inserted into the sliding space 63 from above. A pin lure 1 is formed at the tip of the needle valve 7, and a stopper 72 is formed substantially at the center of the needle valve, facing the spacer 61. A movable core 73 is connected to the upper end of the needle valve 7 so as to face the iron core 4, and the movable core 73 is urged downward by a coil spring 74 disposed between the movable core 73 and the adjustment pipe 42.

A sleeve 8 is press-fitted into the end surface of the body 6 where the injection hole 62 is formed, and a pintle storage portion 81 is provided in the sleeve 8 in correspondence with the injection hole 62 and the pintle 1.
Two jet flow passages 82 are formed to divide the fuel flow from the injection holes 62 into two desired directions.

FIG. 2 shows the main parts of the electromagnetic fuel injection valve 100 of FIG. 1 according to this embodiment, and the structure of the main parts will be explained based on the figure. The pin lure 1 formed at the tip of the needle valve 7 has a cylindrical cylindrical portion 71), a tapered tapered portion 712 that becomes thinner toward the tip, and a thick tapered portion 713 that becomes thicker toward the tip. and a conical tip 7
14, and this pin lure 1 penetrates an injection hole 62 formed in the body 6 and projects to the outside thereof. The tip of the pintle 1 that protrudes from the injection hole 62 is located in a pintle accommodating portion 81 formed in the sleeve 8. The pintle housing part 81 is made up of a substantially cylindrical space, and there is a sufficient distance between the inner circumferential wall surface of the pintle housing part 81 and the pintle 1 so as not to obstruct the flow of the jet of fuel injected from the injection hole 62. It is set.

The pintle storage portion 81 and the external space, that is, the intake passage where the air-fuel mixture is generated, are communicated through two jet passages 82 having the same diameter, and these two jet passages 82 connect the injection holes 62
The jet stream from is diverted. Note that a conical tapered surface 83 is formed at the connecting portion between the pintle storage portion 81 and each jet flow path 82, and the shape of the connecting portion is smooth.

Further, the sum of the flow passage cross-sectional areas of both jet flow passages 82 is sufficiently larger than the fuel flow passage area of the gap between the injection hole 62 and the pin lure 1, that is, the metering portion of the injected fuel.
The size is set so that the flow of the jet is not obstructed by each of the jet channels 82 when the fuel jet is injected from the pintle storage portion 81 and each jet channel 82 and reaches the external space.

Further, each jet flow path 82 is formed symmetrically with respect to the central axis ζ of the pin lure 1 and opened by a predetermined widening angle.

Note that this spread angle is set depending on the mounting position of the intake pipe of this fuel injection valve 100 and the position of each intake valve of the engine.

When an electric signal is supplied to the electromagnetic coil 3 of the fuel injection valve 100, the movable core 73 is attracted toward the iron core 4 against the spring force, and as a result, the needle valve 7 is moved until the spacer 61 and the stopper 72 come into contact with each other. Moving upward, the injection hole 62 is opened, and the pressurized fuel that has reached the outer periphery of the needle valve 7 via the movable core 73 by the adjustment pipe 42 is transferred to the injection hole 62.
More sprayed. Then, this injected fuel is atomized by the pintle 1 in the pintle storage part 81, and the jet of this atomized fuel is guided to the inlet side of each jet flow path 82,
The fuel is injected through each jet flow path 82 toward each intake valve of the engine.

By the way, in order to ensure sufficiently high metering performance even when the fuel injection valve 100 is in the above-mentioned negative pressure or high temperature state, the jet of fuel injected from the injection hole 62 must be directed to the outside as described above. It is necessary for the fluid to flow smoothly until it reaches the space.

According to the present inventors, as shown in FIG.
It has been experimentally confirmed that if +/D2 satisfies D+/Dt≧3, the flow rate does not decrease even under negative pressure or high temperature conditions.

If DI/D2<3, the distance between the pintle 1 and the inner circumferential wall surface of the pintle storage part 81 is narrow, and the bulge of the jet of fuel injected from the injection hole 62 flowing along the pintle 1 is caused by the bulge in the pintle storage part. Due to this contact, the flow of the jet between the pintle 1 and the pintle storage part 81 is poor, and if this part is under negative pressure or high temperature, the generation of paper will be promoted. hand,
This is because the flow of the jet is extremely deteriorated due to vapor generation. However, if D1/D2≧3, pintle lure 1
The bulge of the jet along the line does not come into contact with the inner circumferential wall surface of the pintle storage portion 81, and even if it does, it will hardly affect the flow of the jet, so the flow of the jet in this part is smooth. This is because.

In addition, in each jet flow path 82, in order to allow the jet of fuel atomized in the pintle storage portion 81 to reach the external space without causing a decrease in flow rate, the pintle 1 of the injection hole 62 is connected as described above. The sum of the flow passage cross-sectional areas of the jet flow passages 82 is set to be sufficiently larger than the flow passage area of the gap portion, and by setting the pintle storage portion 81 and each jet flow passage 82 as described above, , high precision metering pressure is guaranteed.

Furthermore, according to the present inventors, as shown in FIG. 4, the fuel flow path area S of the gap between the injection hole 62 and the pin lure 1
and the sum of the flow passage cross-sectional area S2 of each jet flow passage 82: the area ratio St/
It has been confirmed through experiments that if S+ is St/St ≧5.5, the flow rate does not decrease even under negative pressure or high temperature conditions.

If Sz /S+ <5.5, the jet flow path 82 guided to each jet flow path 82 via the pintle storage section 81 will be throttled and the flow will be poor, and under negative pressure or high temperature conditions, this This is because the generation of paper is promoted in some areas, and the flow of the jet stream is extremely deteriorated due to the generation of paper. However, if St/S+≧5.5, the jet flow in each jet flow path 82 will not be restricted and will be smooth.

Further, according to the present inventors, as shown in FIG.
It has also been confirmed through experiments that if the slenderness ratio L/d between the diameter d of 2 and the length L of the jet flow path 82 is L/d≦2, the flow rate does not decrease even under negative pressure or high temperature conditions. are doing.

This is because when L/d>2, the length is too long relative to the diameter d, so a large amount of fuel will adhere to the inner circumferential wall surface of the jet flow path 82, and this adhesion will cause a large amount of fuel to adhere to the inner peripheral wall of the jet flow path 82. This is because the flow of the jet becomes poor, and under negative pressure or high temperature conditions, the generation of paper is promoted in this area, and the flow of the jet becomes extremely poor due to paper generation. However, L/
When d≦2, there is little fuel adhering to the inner peripheral wall surface of the jet flow path 82, and the influence of the adhered fuel on the flow of the jet flow is small, so that the flow of the jet flow within the jet flow path 82 becomes smooth. It is from.

Therefore, when directing the fuel injected from the injection hole 62 in a desired injection direction via the pintle storage portion 81 and each jet flow path 82, by satisfying the conditions in the above embodiment, the pintle storage portion 81 and The jet flow in each jet flow path 82 becomes smooth, so that even if there is a negative pressure or high temperature state, the pintle storage portion 81 and each jet flow path 8
Since the factors that promote paper generation in step 2 are sufficiently reduced, sufficiently high precision metering performance can be guaranteed.

In addition, although the diameter of each jet flow path 82 was made the same in the said structure, it does not matter if it is a different diameter. However, it is not preferable to drastically change the size.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a needle valve that is movably disposed along a sliding space formed inside a body, and a needle valve that is formed at one end of the body and that is opened and closed by the needle valve. an injection hole through which fuel is injected when the valve is opened; the injection hole is formed at the tip of the needle valve and protrudes through the injection hole through a small gap with the injection hole, and the A pintle that moves within the injection hole and is provided with an atomization means for atomizing the fuel injected from the injection hole at its tip; and a tip of the pintle that protrudes from the injection hole is housed;
A pintle storage section consisting of a cylindrical space portion having a diameter sufficiently larger than the passage diameter of the injection hole, and the pintle storage section is communicated with an external space, so that the jet flow injected from the injection hole is divided into two directions. Two jet flow passages are formed corresponding to the injection holes, and a sleeve is provided at the outer end of the body, a diameter D1 of the pintle storage portion and a passage diameter oi of the injection holes.
and the ratio D + / D 2 is Dr / D t≧ 3, and each flow path of the two jet flow paths is smaller than the fuel flow path area S of the gap between the injection hole and the pintle. Sum of cross-sectional areas St
Since the fuel injection valve is characterized by being sufficiently large, the flow of the jet flow is as follows:
Since the jet is smoothly injected into the external space without being constricted, factors that promote vapor generation in the flow path of this jet are sufficiently suppressed.
Even under negative pressure or high temperature conditions, there is very little paper formation, which has the excellent effect of ensuring sufficiently high metering accuracy.

Further, since the fuel atomized by the pintle is injected from each jet flow path, the mixture with air is sufficiently good.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an electromagnetic fuel injection valve which is an embodiment of the fuel injection valve of the present invention, FIG. 2 is a partial sectional view showing main parts of the electromagnetic fuel injection valve shown in FIG. 3 to 5 are graphs showing the experimental results of the present inventors. 1... Housing, 3... Electromagnetic coil, 6... Body. 7... Needle valve, 8... Sleeve, 62... Injection hole. 63...Sliding space, 71...Pintle, 81...
Pintle storage part, 82... Jet flow path, 100... Electromagnetic fuel injection valve. Representative Patent Attorney Takashi Okabe Figure 1 Figure 2 Figure 1--This is a strange DL. Fig. 3 11 → i, It ratio S2/s1 Fig. 4 1). 5225 - Axial lengthening 1A Figure 5

Claims (2)

[Claims] (1) A needle valve movably disposed along a sliding space formed inside the body, and a needle valve formed at one end of the body, opened and closed by the needle valve, and fuel injected when the valve is opened. an injection hole formed at the tip of the needle valve, protruding through the injection hole through a small gap with the injection hole, and moving within the injection hole in response to movement of the needle valve; A pintle, the tip of which is provided with atomization means for atomizing the fuel injected from the injection hole, and a tip of the pintle that protrudes from the injection hole,
A pintle accommodating portion consisting of a cylindrical space having a diameter sufficiently larger than the passage diameter of the injection hole, and communicating the pintle accommodating portion with an external space to divide the jet flow injected from the injection hole into two directions. Two jet flow passages are formed corresponding to the injection holes and include a sleeve set at an outer end of the body, a diameter D_1 of the pintle storage portion and a passage diameter D of the injection holes.
The ratio D_1/D_2 with _2 is D_1/D_2≧3, and the sum of the cross-sectional areas of each of the two jet flow paths is smaller than the fuel flow path area S_1 of the gap between the injection hole and the pintle. S
A fuel injection valve characterized in that _2 is sufficiently larger. (2) The ratio S_2/S_1 of the channel area S_1 of the injection hole and the sum S_2 of the channel cross-sectional areas of the jet channels is S_2/
The fuel injection valve according to claim 1, wherein S_1≧5.5. (3)
3. The fuel injection valve according to claim 1, wherein the two jet passages have the same diameter. (4) The fuel injection valve according to claim 3, wherein the ratio L/d between the diameter d and the length L of the jet flow path is L/d≦2.