JPH05133306A - Fuel injection valve for engine - Google Patents

Abstract

PURPOSE:To atomize the injection fuel of an engine with a small quantity of air and to perform the atomization even under specification of plural air intake valves per cylinder. CONSTITUTION:When a measuring valve 4 is separated from a seat 8 to be opened, a fuel is circulated in a fuel circulating orifice 7B by a fuel circulating member 7 provided upstream from a measuring orifice 9. An air circulating orifice 11B is provided downstream from the measuring orifice 9. In this orifice 11B, the circulating fuel collides with a reversely circulating air flow so that the fuel is properly decelerated while it is atomized. Then, the fuel and air pass through a mixing promoting orifice 14 with a reduced diameter smaller than that of the orifice 11B. In this small space 14, the fuel and air are efficiently mixed together so that the atomization of the fuel with the small quantity of air can be performed. The atomized fuel is injected from an outlet 15. The orifice 14 may be branched corresponding to each of a plurality of suction valves.

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 engine, and more particularly to a technique for atomizing injected fuel.

[0002]

2. Description of the Related Art The fuel injected from a fuel injection valve of an engine is mixed with air more finely as it is atomized, which leads to improvement of accuracy of air-fuel ratio and further improvement of drivability and exhaust gas purification. Therefore, conventionally, for example, JP-A-57-1107
As disclosed in Japanese Patent Publication No. 69, an annular gap for guiding a part of the air in the intake passage through the air bypass passage is formed around the injection nozzle, and the air flow coming out of the annular gap collides with the injected fuel. As disclosed in Japanese Patent Laid-Open No. 64-24161, the injected fuel is swirled and an air flow whose swirling direction is opposite to that of the injected fuel collides with the injected fuel.

[0003]

However, when the swirling fuel injected as described above is collided with an air stream to be atomized, conventionally, sufficient consideration has not been given to reducing the amount of atomizing air. ..

That is, when there is a large amount of air for atomization,
The particle size of the fuel can be reduced, but when applied to an actual engine, if the air for atomization is too much, the ratio of the air in the cylinder to the fuel cannot be optimized, and the exhaust gas Purification performance and drivability deteriorate. In particular, when the amount of fuel is small, such as during idle operation, the atomizing air tends to be relatively excessive.

The present invention has been made in view of the above points, and a first object thereof is to achieve efficient atomization of fuel with a small amount of air.

A second object is to achieve efficient atomization of fuel with a small amount of air even if the engine has a plurality of intake valves per cylinder.

[0007]

As a basic means for solving the first problem, a fuel swirling orifice for swirling fuel is provided upstream of a fuel metering orifice, and a fuel swirling orifice is provided downstream of the metering orifice. Is provided with an air swirling orifice that applies a swirling force to the air flow in the direction opposite to the swirling direction of the fuel while introducing the air flow, and the swirling fuel injected through the swirling air and the metering orifice at this air swirling orifice And a fuel / air mixture promoting orifice having a smaller diameter than the air swirling orifice is provided downstream of the air swirling orifice (this is the first problem solving means. ).

As a basic means for solving the second object, one is to provide a fuel swirling orifice upstream of the fuel metering orifice, an air swirling orifice downstream of the fuel metering orifice, and an air swirling orifice as described above. Downstream of the orifice for
A fuel / air mixture promoting orifice having a smaller diameter than the air swirling orifice was formed in a branch manner corresponding to a plurality of intake valves per cylinder of the engine (this is referred to as a second problem solving means A).

The other is to provide a fuel swirling orifice for swirling the fuel upstream of the fuel metering orifice, and the swirling fuel to be injected corresponds to a plurality of intake valves per cylinder of the engine downstream of the metering orifice. A first branch orifice (a branch orifice means an assembly of a plurality of branch elements) for further distribution, and further downstream of the first branch orifice, a branch is provided in the same manner as the first branch orifice. A second branched orifice provided,
It is set that the swirling force and the swirling fuel collide with each other by applying a swirling force to the air flow in the direction opposite to the swirling direction of the fuel while introducing the air flow at each orifice of the second branch orifice (this Is referred to as a second problem solving means B).

[0010]

Operation of the first problem solving means: Fuel is swirled by the fuel swirling orifice upstream of the metering orifice and is injected from the metering orifice to the air swirling orifice.
When the fuel is swirled upstream of the metering orifice as described above, the pressure loss can be reduced as compared with the method of swirling the fuel downstream of the metering orifice.

In the air swirling orifice, the swirling air and the swirling fuel collide with each other by swirling the air flow in the direction opposite to that of the fuel. Since the swirling air flow and swirling fuel flow collide with each other at a position close to the outlet of the metering orifice, atomization starts before the fuel spreads. Further, since the air and the fuel collide with each other in the opposite direction, the relative velocity of the air and the fuel is large, and the atomization is actively performed. Furthermore, since the air and fuel combined at the air swirling orifice pass through an orifice (fuel / air mixing promotion orifice) that has a smaller diameter than the air swirling orifice, air and atomized fuel can be stored in a small space during this passage process. The mixing of the two is efficiently promoted, and as a result, the atomization of the fuel is further achieved with a small amount of air, and thereafter the atomized fuel is ejected.

Operation of the second problem-solving means A ... The process in which the fuel and the air collide with each other at the air swirling orifice is the above first step.
The fuel and air are distributed and guided to the branch orifice downstream of the air swirling orifice. Since each of these branch orifices has a smaller diameter than the air swirling orifice, it efficiently promotes the mixing of air and atomized fuel in a small space during this passage process. Further, the fuel is atomized, and thereafter the atomized fuel is ejected while being distributed toward each intake valve.

Operation of Second Problem Solving Means B ... The swirling fuel is distributed at the first branch orifice immediately after being injected from the metering orifice, and swirls in the direction opposite to the swirling fuel at the second branch orifice. It collides with the air flow, which promotes atomization of the fuel passing through each branch orifice. Further, since the air required for atomization is guided to the second branch orifice, which is a small space, the atomized fuel corresponds to each intake valve while efficiently atomizing the fuel with a small amount of air. It is distributed and spouts.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of the essential parts showing a first embodiment of the present invention, and FIG. 2 is a longitudinal sectional view thereof.

In FIG. 2, reference numeral 1 denotes an electromagnetic fuel injection valve. Inside the main body, an electromagnetic coil 2, a fixed core 3, a plunger 5 with a ball valve (measuring valve) 4, a return spring 6, a fuel swirler 7, etc. Is incorporated. When the electromagnetic coil 2 is not energized, the ball valve 4 is brought into pressure contact with the valve seat 8 provided downstream of the fuel swirl 7 by the force of the spring 6 to be closed. When energizing the electromagnetic coil 2, the core 3, the yoke 10, the plunger 5
Forms a magnetic circuit, the ball valve 4 is magnetically attracted together with the plunger 5, and the ball valve 4 is separated from the valve seat 8 and opened.

As shown in FIG. 4, the fuel swirler 7 is formed of a piece-shaped chip, and four fuel passage grooves 7A for imparting a swirling force to the fuel are provided on the lower surface thereof. The groove 7A has a passage structure for guiding the fuel from the side wall of the chip to the fuel swirling orifice 7B in the center of the chip, and each groove 7A is arranged offset with respect to the center of the fuel swirling orifice 7B. It is arranged so as to maintain a substantially tangential relationship with the peripheral surface of the working orifice 7B. In this way, when the valve is opened, the pressurized fuel discharged from the groove 7A becomes a swirling flow along the wall surface of the fuel swirling orifice 7B as shown in FIG. 4, and passes through the metering orifice 9 provided downstream of the swirling flow. It is injected into the air swirling orifice 11B.

The air swirling orifice 11B is formed at the center of the piece tip (air swirler) 11 as shown in FIG. 4, and is located immediately below the metering orifice (fuel injection orifice) 9 downstream of the ball valve 4. Are arranged. As shown in FIGS. 3A and 4, the air swirler 11 has four air passage grooves 11A on its upper surface for imparting a swirling force to the air. Each groove 11A has a passage structure for guiding air from the side wall of the tip to the air swirling orifice 11B at the center of the tip, and each air passage groove 11A is arranged offset with respect to the center of the air swirling orifice 11B. The air passage groove 11A is arranged so as to maintain a substantially tangential relationship with the inner circumference of the air swirling orifice 11B. The arrangement structure of this groove 11A is
The direction of the air swirl flow is set to be opposite to the above-described fuel swirl flow. The air swirling orifice 11B is shown in FIG.
As shown in (b), the lower portion 11B 'is formed into a conical shape by drawing.

Stainless steel is used as the material of the fuel swirler 7 and the air swirler 11. When alcohol is used as the fuel, the portions of the metering valve 4, the fuel swirling orifice 7B, the air swirling orifice 11B, and the fuel / air mixing promoting orifice 14 that come into contact with the fuel are subjected to corrosion resistance treatment by nickel plating or the like. .. Air swirling orifice 11B
Is formed by machining, die casting, sintering of metal powder, etching treatment, or the like. Further, it may be processed and formed by micromachining using ceramic or silicon as a material.

A cover 12 is attached to the lower portion of the main body of the fuel injection valve 1 so as to surround the air swirling orifice 11. An annular passage 13 is formed between the inner wall of the cover 12, the outer wall of the air swirler 11, and the outer wall of the lower portion of the main body of the fuel injection valve. One end 16 ′ of an air conducting pipe 16 is attached to the cover 12, and the other end of the air conducting pipe 16 is connected, for example, to the upstream side of the throttle valve of the intake pipe, so that a part of the air in the intake pipe is above the throttle valve, Air is introduced into the annular air passage 13 and further the air swirl 11 by utilizing the downstream differential pressure, and when the differential pressure becomes equal to or lower than a predetermined pressure, a means such as supply using an air pump is taken. There is.

The air swirler 11 is arranged so as to be interposed between the cover 12 and the lower part of the main body of the fuel injection valve 1. The upper part of the air swirling orifice 11B is in contact with the outlet of the metering orifice 9, and the lower part 11B 'of 11B'. Contacts an orifice 14 provided in the cover 12 for promoting fuel / air mixing. The orifice 14 for promoting fuel / air mixing has a small diameter that is the same as the most narrowed portion of the air swirling orifice 11B.
A fuel spray outlet 15 having a larger diameter than the orifice 14 is formed downstream of the orifice 14 for promoting fuel / air mixing. The cover 12 is fixed to the fuel injection valve main body by press fitting or metal flow.

According to the present embodiment, when the valve is opened, the fuel swirls through the fuel swirling orifice 7B, passes through the metering orifice 9, and is jetted into the air swirling orifice 11B in the form of a thin liquid film. In this case, the fuel is the metering orifice 9
Since the swirling force is applied upstream of, the pressure loss is smaller than that of the system in which the swirling force is applied to the fuel downstream of the metering orifice, and the ejection speed can be increased accordingly.

On the other hand, in the air swirling orifice 11B,
As described above, the swirling air swirling in the direction opposite to the swirling fuel is generated, and the air passage groove 11 for swirling the air is generated.
Since the outlet of A is arranged near the outlet of the metering orifice 9, swirling fuel injected from the metering orifice 9 immediately joins the swirling air flow, and the swirling directions of the fuel and air are opposite to each other. Atomization is performed while increasing the relative velocity of fuel. Next, since the atomized fuel and air pass through the mixing promoting orifice 14 that is narrower than the air swirling orifice 11, the atomized fuel and air are efficiently mixed without escape and then through the outlet 15. The mixed fuel is sprayed into the intake pipe.

According to the present embodiment, due to the above-mentioned action, the efficient mixing of the fuel and the air can be satisfactorily performed with a small amount of air, and the atomization of the fuel can be improved. In addition, it is possible to effectively reduce the speed of the injected fuel and effectively prevent the injected fuel from adhering to the intake pipe wall.

FIG. 5 shows the relationship between the atomizing air amount Qa and the particle size of the spray. The combination of the air swirling type and the mixing promoting orifice as in this embodiment is simply an air swirling type or air type. The result is that atomization can be achieved with a smaller amount of air compared to the collision type.

FIG. 6 shows an example of a conventional air collision type fuel injection valve used to obtain the experimental data shown in FIG. 5, and the same reference numerals as those in the above-mentioned embodiments indicate the same or common elements. In the case of the conventional air collision type, as shown in FIG. 6, the air is not swirled, and the air is made to directly collide with the injected fuel through a small orifice or slit. Therefore, unless the air is ejected from the small orifice 60, the air cannot be made to collide with the fuel uniformly, and large particles are generated. Further, when air is ejected from a small orifice, the orifice is apt to be clogged due to contamination of air, exhaust gas recirculation, and freezing of water, resulting in low reliability. Further, there is a problem that the atomization speed is high and the atomized spray adheres to the inside of the intake pipe.

FIG. 7 shows the relationship between the atomizing air flow rate Qa and the atomized particle diameter when the swirling direction of the air flow is changed. When the amount of atomizing air is increased, the particle size is reduced, but when the swirling direction of the air is opposite to the fuel, atomization can be performed with less air than in the case of the forward direction.

FIG. 8 shows data relating to the effect of fuel swirling. When the fuel is not swirled, the fuel is not sufficiently atomized and the particle size is large. When the fuel is made to collide into a thin film by colliding a conical portion protruding from the tip of the valve like a pintle type, it atomizes even in the absence of air, but the relative velocity with air is small, so the particle size is large. Further, when swirling is applied, if the swirling is done downstream of the metering orifice, the pressure loss of the fuel is large. Therefore, even if the swirling air flows in the direction opposite to the fuel swirling direction are merged later, the particle size is the same as in this embodiment. The particle size is larger than that of the method in which the fuel is swirled upstream. That is, when the swirl was added to the fuel upstream of the metering orifice and the air swirling flows in the opposite direction were merged downstream of the metering orifice, the particle size of the fuel could be minimized.

FIG. 9 shows the radial distribution of the particle size when finely measuring the particle size of the spray with a laser. In the air collision type, atomization is performed only on the outside where the air hits, and large particles are present in the central part. In the air swirl type of the present embodiment, since air and fuel collide sufficiently, large particles do not exist in the central portion either, and the atomized state can be made substantially evenly.

FIG. 10 shows atomizing air when the size of the outlet diameter of the air swirling orifice 11B in this embodiment (φd shown in FIG. 3 and also the diameter of the fuel / air mixing promoting orifice 14) is changed. The relationship between the flow rate Qa and the spray particle size is shown. φd is 3 mm for nozzle A and 2.5 m for nozzle B
m and 2 mm for the nozzle C. When the dimension d of the orifice 14 is reduced, the mixing of air and fuel is promoted, and atomization can be performed with less air.

FIG. 11 shows the relationship between the injection pulse width and the fuel flow rate when the outlet diameter φd of the air swirling orifice 11B is changed as described above. As described above, in the nozzle A, the nozzle B, and the nozzle C, the diameter of the orifice 14 is a factor for atomizing the fuel with a small air flow rate, but if φd is reduced like the nozzle C, the pressure of the atomizing air is reduced. Becomes larger, the fuel injection amount becomes smaller. This is because as the atomizing air pressure increases, the pressure at the fuel outlet increases and the difference from the fuel supply pressure decreases. Note that ΔPa shown in FIG. 11 is the difference between the supply air pressure Pa and the intake pipe internal pressure Pb. In the case of the nozzle C, the above problem can be solved by using the atomizing air pressure or the fuel outlet pressure as the reference pressure of the fuel pressure regulator without using the intake pipe internal pressure.

FIG. 12 shows the relationship between the supply air pressure Pa and the atomized particle size. When the area of the air swirling orifice 11B is increased, the atomization air amount is increased, and atomization can be performed with a small pressure. Therefore, when using an air pump,
In the structure capable of supplying only low pressure, the area of the air swirling orifice may be increased.

FIG. 13 shows an example of a supply system of atomizing air in the fuel injection valve of the above embodiment.

In FIG. 13, the fuel injection valve 1 is arranged for each manifold of the intake pipe 40, and is provided downstream of the air cleaner 18 and the air flow meter 19 and from upstream of the throttle valve 20 to the common conduit 16 ′, the air distributor 17, and each. The atomizing air is introduced into the air swirling orifice 11B via the branch pipe 16 connected to the fuel injection valve.

Since the pressure in the intake pipe downstream of the throttle valve 20 is lower than that upstream of the throttle valve due to pressure loss at the throttle valve 20, passage loss in the intake pipe, and engine suction, the differential pressure Δ
Air flows to the fuel injection valve 1 by Pa. Further, since the differential pressure ΔPa is small when the throttle valve is fully opened, the air pump 21 may be provided.

In this case, in order to increase the velocity of the air at the air swirling orifice 11B, the differential pressure between the inside of the intake pipe and the inside of the intake pipe is set to 0.
The pressure is preferably 5 atm or more. Also, all injection valves 1
Air distributor 1 than the total area of the air swirling orifice of
Enlarge common air conduit 16 'to 7. In addition, each branch pipe 16 from the air distributor 17 is connected to one injection valve 1
The area is larger than the area of the air swirling orifice 11B.
If this is not done, the air flow will be throttled in the middle of the passage. The air swirling orifice 11B cannot form a high-speed air flow.

FIG. 14 shows another example of the fuel atomizing air supply system. Also in this example, as in the air supply system of FIG. 13, air is taken in at the downstream of the air cleaner 18, the air flow meter 19 and at the upstream of the throttle valve 20, and the air is taken in via the common pipe 16 ′, the pump 21, the air distributor 17, and the branch pipe 16. Although it is guided to the air swirling orifice 11B of the fuel injection valve 1, the air distributor 17
An air pressure regulator 22 is attached to the air distributor 17 to keep the pressure inside constant.

As a result, the pressure of the atomizing air can be kept constant, and the atomization of fuel can always be stably performed. In the unlikely event that the air swirling orifice 1
Even when the passage system reaching 1B (for example, the groove 11A) is clogged, the pressure of the pressure distributor 17 is prevented from rising abnormally excessively.

FIG. 15 shows another example of the fuel atomizing air supply system and the fuel supply system. Also in this embodiment, the atomizing air is taken in from the downstream of the air cleaner 18 and the air flow meter 19 and from the upstream of the throttle valve 20, and the common pipe 16 ′ and the pump 2 are used.
1, the air distributor 17, and the branch pipe 16 to guide the air swirling orifice 11B of the fuel injection valve 1. further,
The fuel supply system is configured as follows.

That is, the fuel is pressurized by the fuel pump 25 provided in the fuel supply pipe 24, and this fuel pressure is corrected by the fuel pressure regulator 26 in accordance with the pressure Px of the fuel injection portion (air swirling orifice 11B). It

As shown in FIG. 16, the fuel pressure regulator 26 includes a diaphragm 28 with a check valve 27 and a spring 29 inside the main body, and the pressure downstream of the throttle valve 20 via the pressure conduit 23 on the working chamber 26A side. Air distributor 17
The supply air pressure Pa therein is introduced. The pressure Px of the fuel injection portion 11B is equal to the pressure Px in the intake pipe as expressed by the following equation.
Since it depends on both b and the supply pressure Pa of atomizing air,

[0041]

## EQU1 ## Px = X.Pa + Y.Pb X, Y is a weighting coefficient.

The fuel pressure regulator 26 operates so as to maintain a predetermined differential pressure with respect to Px. Further, throttles 23a and 23b are placed in the respective conduits 23 for guiding Pa and Pb to the working chamber 26A of the regulator 26 so that the fuel flow rate is adjusted not to depend on the pressure in the intake pipe and the pressure of the atomizing air. It is a thing.

FIG. 17 is a cross-sectional view of essential parts according to the second embodiment of the present invention.

The fuel injection valve 1 of this embodiment is applied to a type in which a plurality of (for example, two) intake valves are arranged in each cylinder of the engine. The drive mechanism of the injection valve is similar to that of each of the above-described embodiments, and the fuel swirler 7 is arranged upstream of the metering orifice 9. Air swirling orifice 11 formed in air swirler (chip) 11 downstream of the metering orifice
B is straight, and a branching tip 30 for distributing the injected fuel is disposed downstream of the straight tip. This branching tip 30
In this, branch orifices 30A and 30B corresponding to the intake valves are formed.

In this embodiment, the air swirling orifice 11 is used.
Although the fuel and air are mixed in the lower part of B, the branch orifices 30A and 30B are narrowed down more narrowly than the orifice 11B, so that the mixing of the atomized fuel and air is promoted in this branch orifice, and as a result, further fine particles are obtained. Promotion is promoted. The branch orifices 30A and 30B also serve as orifices for promoting air / fuel mixing.

The inlets of the branch orifices 30A and 30B may be in contact with each other, but the inlets may partially overlap each other.

FIG. 18 shows the relationship between the orifice diameter D of the branch orifices 30A and 30B and the spray particle size. When the amount of air is small, the particle size becomes smaller as the dimension D becomes larger. This is because the spray is ejected without adhering to the branch portion.
When the amount of air is small, it depends on the atomization by the fuel swirling of the fuel injection valve, so it is better that the fuel does not adhere to the branch portion. On the other hand, when the amount of air is large, the smaller the dimension D is, the more the air and the fuel are mixed, and the better the atomization. Considering the above, an appropriate dimension D is set.

Similarly, if the length 1 of the branch orifice is increased, the particle size of the spray becomes large when the amount of air is small, and becomes small when the amount of air is large. FIG. 19 shows the relationship between the diameter D of the branch orifice and the spray angle θ1. As D increases, the spray angle θ ₁ increases. If the length 1 of the branch orifice is 2 mm or less, the spray angle becomes too large when air is introduced, and the spray cannot be formed in two directions. Therefore, l needs to be 2 mm or more. This point is important in forming the spray in two or more directions by air atomization. With this injection valve, D = 2.5 mm, l =
4 mm is preferable.

FIG. 20 shows the spraying condition of the above embodiment.
The spray is formed in two directions. Two spray directions θ
Can be arbitrarily changed by the angle of the branch orifice.

FIG. 21 shows a third embodiment of the present invention.

The difference between this embodiment and the second embodiment shown in FIG. 17 is that a fuel branching tip (first branching orifice) 32 is arranged just below the metering orifice 9 and downstream of the metering orifice 9. This is because the tip 33 that doubles as a swirler and a fuel branch is provided. The tip 33 has a second branch orifice 33
A and 33B are arranged, and as shown in FIG. 22, a branch orifice 33A, on its upper surface (right side in FIG. 22A).
An air passage groove 34 that is offset with respect to 33B is provided. The air passage groove 34 introduces air from the annular air passage 13 and generates an air swirling flow in the branch orifices 33A and 33B. The preferred dimensions for forming the two sprays are D = 2 mm and l = 5 mm.

In this embodiment, after the swirling fuel is branched by the fuel branching tip 32, the branching orifices 33A, 33B are provided.
Collides with the swirling air flow at the branch orifice 33.
A and 33B efficiently mix the atomized fuel and air.

FIG. 23 shows another mode of the fuel branching tip 32.

In this embodiment, two branch orifices 3 are provided.
2A and 32B, and a slit 32C connecting these orifices. The fuel to which the swirling force is applied by the fuel swirler 7 is ejected from the metering orifice 9, but the swirling flow can be guided to the two sprays without loss by the fuel branching tip 32 having the above configuration. Therefore, when the air is swirled in the direction opposite to this fuel, the relative swirling speed of the air and the fuel is increased, and atomization can be performed with less air.

FIG. 24 shows the positional relationship between the fuel branching tip 32 and the air swirler / fuel branching tip 33 described above. Since the fuel is swirling, the direction of the fuel ejected from the orifices 32A and 32B of the fuel branching tip 32 does not match the direction of the slit 32C, and the angle deviates by θ3. In consideration of the above, in this embodiment, the orifices 33A and 33B are displaced by the angle θ3 in order to guide the fuel to the orifices 33A and 33B without loss.

FIG. 25 shows another shape of the fuel branching tip 30 used in FIG. In order to divide the fuel from the fuel metering orifice 9 into two directions without the loss of swirling, the branch orifices 30A and 30B of the fuel branching tip 30 are aligned with the advancing direction of the swirling fuel, and their outlets have respective angles of θ.
It is offset by 3. As a result, the swirled fuel is branched with almost no loss, so that the particle size of the spray can be reduced even when the amount of air is small.

FIG. 26 shows another shape of the air swirling orifice 33 in FIG. In order to divide the fuel from the fuel branch tip 32 into two without turning loss,
Each orifice 33A, 33 of the air swirling orifice 33
B is aligned with the advancing direction of the swirling fuel, and the outlets thereof are each shifted in angle by θ3. Also in this case, the swirled fuel is branched into two without loss, so that there is an advantage that the particle size of the spray can be made small even when the amount of air is small.

[0058]

According to the first means for solving the problems, the fuel is swirled upstream of the metering orifice, swirled and collided with the fuel in the direction opposite to the swirling direction of the fuel downstream thereof, and further swirling air downstream thereof. By providing the mixing promoting orifice having a smaller diameter than the orifice, it is possible to efficiently atomize the fuel with a small amount of air.

Therefore, the air-fuel ratio control of the engine is easy, and the number of revolutions does not increase during idle operation. Further, when an air pump for producing air pressure is used, the capacity of the pump can be reduced.

According to the second and third problem solving means, in addition to the same effect as the first problem solving means, it is possible to cope with an engine having a plurality of intake valves per cylinder.

As described above, since a fine fuel can be supplied to the engine, mixing of air and effort is promoted, and unburned hydrocarbons can be reduced especially during exhaust gas purification. In addition, the fuel supply during acceleration / deceleration becomes faster, and the compensating fuel can be reduced.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part of a fuel injection valve according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of the above embodiment.

FIG. 3 is a plan view of an air swirling orifice used in the above embodiment and a cross-sectional view taken along line AA thereof.

FIG. 4 is an operation explanatory diagram of the above embodiment.

FIG. 5 is a diagram showing the data of atomizing air amount-spray particle size characteristics of the product of the present invention of the above-described example and the prior art.

FIG. 6 is a partial sectional view of a conventional fuel injection valve having an air collision type orifice.

FIG. 7 is a diagram showing the data of atomization air amount-atomization particle size characteristics when the fuel and the atomization air flow are swirled in the reverse swirl direction and the forward swirl direction to collide.

FIG. 8 is an amount of atomizing air when the fuel and the atomizing air flow are swirled in the opposite direction to collide with each other, the fuel is swirled upstream and downstream of the metering orifice, and when the fuel is not swirled- The figure which shows the data of a spray particle diameter characteristic.

FIG. 9 is a diagram showing the atomization distribution in the radial direction when using the fuel swirl type of the air swirl type of the embodiment and the conventional air collision type.

FIG. 10 is a diagram showing the data of atomizing air amount-spray particle size characteristics when the diameter of the air swirling orifice of the above embodiment is changed.

11 is a diagram showing fuel injection pulse width-fuel flow rate characteristic data under the condition of FIG.

FIG. 12 is a diagram showing the data of the differential pressure ΔPa between the pressure of atomizing supply air and the outlet pressure of the fuel injection valve-spray particle size characteristics.

FIG. 13 is an explanatory view showing an example of an atomizing air supply system of the above embodiment.

FIG. 14 is an explanatory view showing another example of the atomizing air supply system of the above embodiment.

FIG. 15 is an explanatory view showing another example of the atomizing air supply system of the above embodiment together with the fuel supply system.

16 is a vertical cross-sectional view showing an example of a fuel pressure regulator used in FIG.

FIG. 17 is an enlarged sectional view of a main part of a fuel injection valve according to a second embodiment of the present invention.

FIG. 18 is a diagram showing a relationship between the outlet diameter φD of the branch orifice and the atomized particle diameter in the second embodiment.

FIG. 19 is a diagram showing a relationship between a branch orifice outlet diameter φd and a spray angle in the second embodiment.

FIG. 20 is an explanatory view showing the situation of spraying of the second embodiment.

FIG. 21 is an enlarged cross-sectional view of main parts of a fuel injection valve according to a third embodiment of the present invention.

FIG. 22 is a vertical sectional view and a plan view of an air swirling / fuel branching orifice used in the third embodiment.

FIG. 23 is an explanatory view showing a part of components used in the third embodiment and their operating states.

FIG. 24 is an explanatory diagram showing an example of the positional relationship between the fuel branch orifice and the air swirl / fuel branch orifice used in the third embodiment.

FIG. 25 is a plan view showing an example of a branch orifice used in the second embodiment.

FIG. 26 is a plan view showing an example of an air swirl / fuel branch orifice used in the third embodiment.

[Explanation of symbols]

1 ... Fuel injection valve, 4 ... Metering valve, 7 ... Fuel swirler, 7A ...
Fuel passage groove for imparting swirl force, 7B ... Orifice for air swirl, 8 ... Valve seat, 9 ... Metering orifice, 11 ... Air swirler, 11A ... Air passage groove for imparting swirl force, 11B ... Orifice for air swirl, 12 ... Cover, 13 ... Air passage, 1
4 ... Orifice for promoting fuel / air mixing, 16 ... Air conduit, 16 '... Air common conduit, 17 ... Air distributor, 19 ...
Air flow meter, 20 ... Throttle valve, 21 ... Pump, 22
… Air pressure regulator, 24… Fuel supply piping, 25…
Fuel pump, 26 ... Fuel pressure regulator, 30 ... Branch tip, 30A, 30B ... Fuel branch orifice, 3
2 ... Orifice for fuel branching, 33 ... Tip for branching, 33
A, 33B ... Orifices for air swirling and fuel branching.

Claims (13)

[Claims] 1. A fuel swirling orifice for swirling fuel is provided upstream of a fuel metering orifice, and an air flow is introduced downstream of the metering orifice while swirling in the direction opposite to the fuel swirling direction. An air swirling orifice for applying force is provided, the swirling air is set to collide with the swirling fuel injected through the metering orifice at the air swirling orifice, and the air swirling orifice is provided downstream of the air swirling orifice. A fuel injection valve for an engine, which is provided with a fuel / air mixing promoting orifice having a diameter smaller than that of the air swirling orifice. 2. The fuel injection valve for an engine according to claim 1, wherein the air swirling orifice has a passage structure in which at least a downstream side thereof is conically narrowed and communicates with the fuel / air mixing promotion orifice. .. 3. The fuel injection valve for an engine according to claim 1, wherein the air swirling orifice is arranged close to the metering orifice. 4. A fuel swirling orifice for swirling fuel is provided upstream of the fuel metering orifice, and an air flow is introduced downstream of the metering orifice while swirling in the direction opposite to the fuel swirling direction. An air swirling orifice for applying force is provided, the swirling air is set to collide with the swirling fuel injected through the metering orifice at the air swirling orifice, and the air swirling orifice is provided downstream of the air swirling orifice. A fuel injection valve for an engine, characterized in that a fuel / air mixing promotion orifice having a smaller diameter than the air swirling orifice is formed in a branched manner corresponding to a plurality of intake valves per cylinder of the engine. 5. The fuel injection valve for an engine according to claim 4, wherein an outlet side of the fuel / air mixing promotion orifice (branch orifice) is offset in accordance with a traveling direction of swirling fuel. 6. A fuel swirling orifice for swirling the fuel is provided upstream of the fuel metering orifice, and the swirling fuel to be injected is provided downstream of the metering orifice in correspondence with a plurality of intake valves per cylinder of the engine. A first branch orifice for distribution (herein, “branch orifice refers to an assembly of a plurality of orifices serving as branch elements”) is provided, and further downstream of the first branch orifice, the branch is made in the same manner as the first branch orifice. And a swirling force is imparted to the air flow in the direction opposite to the swirling direction of the fuel while introducing the air flow into each of the second branch orifices. A fuel injection valve for an engine, characterized in that it is set to collide with. 7. The fuel injection valve for an engine according to claim 6, wherein an outlet side of the second branch orifice is offset in accordance with a course direction of the swirling fuel. 8. The fuel injection valve according to any one of claims 1 to 7, wherein the fuel injection valve is arranged for each manifold, and the air swirling orifice or the second branch orifice provided in each fuel injection valve is provided. Is a fuel injection valve for an engine, characterized in that air is taken from an upstream side of a throttle valve downstream of an air flow meter in an engine intake passage and is guided through an air distributor. 9. The engine according to claim 8, wherein air upstream of the throttle valve downstream of the air flow meter is introduced into the air swirling orifice or the second branch orifice via a pump. Fuel injection valve. 10. The fuel injection valve for an engine according to claim 9, wherein the air distributor is provided with an air pressure regulator. 11. The fuel supply pipe with a fuel pump for supplying fuel to the fuel injection valve according to any one of claims 1 to 10, wherein the pressure of the fuel injection space near the outlet of the metering orifice. On the other hand, the fuel injection valve of the engine is provided with a fuel pressure adjusting regulator for maintaining the fuel pressure at a predetermined differential pressure. 12. The fuel metering valve according to claim 1, a fuel swirling orifice,
A fuel injection valve for an engine, characterized in that the metering orifice, the air swirling orifice, the branch orifice, and the fuel / air mixing promoting orifice are plated with nickel. 13. The fuel metering valve, fuel swirling orifice according to claim 1,
A fuel injection valve for an engine, characterized in that a metering orifice, an air swirling orifice, a branch orifice, and a fuel / air mixing promoting orifice are processed and molded by ceramic or silicon micromachining.