JPH05332223A - Fuel feeding device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of any fluctuation in a fuel amount owing to a pressure difference during assist air and to provide spray through which atomization is improved at a narrow spray angle. CONSTITUTION:A sleeve 24 is attached in front of a fuel injection valve. The sleeve 24 is provided with two fuel nozzle 28 and 30 through which fuel injected through the nozzle of a fuel injection valve is allowed to flow, and an air nozzle through which assist air is brought into collision with injected fuel. The air nozzle comprises atomization controlling air nozzles 40, 42, 46, and 48 to promote atomization of fuel injected through the fuel nozzles 28 and 30 and direction controlling air nozzles 44 and 50 to control the direction of fuel injected through the fuel nozzles 28 and 30. The skirt of the sleeve 24 guides fuel and assist air injected through the two fuel nozzles 28 and 30 and the air nozzles 40, 42, 46, 48, and 50 respectively to an intake air passage. This constitution makes assist air to collide with fuel injected from the front side of the fuel nozzles 28 and 30 formed in the sleeve 24 to mix them together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for an internal combustion engine, and more particularly to a fuel supply system for improving the atomization of fuel by causing assist air to collide with fuel injected from a fuel injection valve.

[0002]

2. Description of the Related Art As a prior art, the actual Kaihei 1-61461
What is disclosed in the publication is known. In this technique, the injection direction of each injection hole of the fuel injection device having two injection holes is directed toward each intake valve to reduce the fuel adhesion to the intake passage. Further, in JP-A-63-314363, an assist air injection hole is formed in the same direction as each fuel injection hole of the fuel injection device, and the atomization of fuel is improved by the assist air. In this publication, the sleeve is divided into an outer tubular member and an inner member in which a fuel passage is formed, and an assist air passage that penetrates the outer tubular member is provided.
An assist air passage is formed on the mating surface of the outer tubular member and the inner member.

Further, Japanese Unexamined Patent Publication No. 64-24161 discloses a cylindrical surface which will guide the spray to the portion after the collision of the fuel and the air.

[0004]

However, in the above-mentioned prior art, the method of applying the assist air to the fuel is insufficient, the spray angle is wide, and the effect of atomization cannot be sufficiently obtained. Further, in the prior art in which the assist air is ejected into the injected fuel, there is a problem that the injected fuel amount is likely to vary due to the pressure difference between the pressure at the collision portion of the assist air and the fuel and the pressure inside the fuel injection valve.

The problem to be solved by the present invention is to provide a fuel supply for an internal combustion engine of an assist air system in which the fuel amount does not fluctuate due to a pressure difference during assist air and a spray with good atomization can be obtained with a narrow spray angle. It is to provide a device.

[0006]

A fuel supply device for an internal combustion engine according to the present invention for solving the above problems includes a fuel injection valve having an injection hole for injecting and supplying fuel toward an intake passage of the internal combustion engine; A plurality of fuel injection holes for circulating the fuel injected from the injection holes, a plurality of air injection holes for colliding assist air with the fuel injected from the plurality of fuel injection holes, and the plurality of fuel injection holes and the plurality of fuel injection holes A sleeve having a skirt for guiding the fuel and the assist air injected from the air injection hole to the intake passage, and the plurality of air injection holes are concentric with the sleeve center so as to surround the plurality of fuel injection holes. And an atomization control air nozzle for promoting atomization of the fuel injected from the fuel injection hole, and a direction control air nozzle for controlling the direction of the fuel injected from the fuel injection hole. And an axial end of the skirt is set at an axial position closer to the fuel injection valve than a collision position between an extension line of the fuel injection hole and an extension line of the air injection hole. And

[0007]

According to the above-mentioned structure of the present invention, the fuel injected from the fuel injection hole is collided with the assist air from the atomization control air injection hole and the direction control air injection hole, and the atomization control of the fuel spray is performed. Direction control is performed. Since the collision center position between the injected fuel and the assist air is on the front side in the injection direction of the skirt, it is possible to further atomize the fuel while keeping the spray angle of the fuel at a narrow angle. In this case, the assist air from the atomization control air injection hole controls the fuel injection direction to the center side, and the assist air from the direction control air injection hole prevents the spray angle from expanding.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 2, a throttle valve 3 is provided in the middle of an intake pipe 2 of an internal combustion engine 1, and a fuel supply device 5 to which the present invention is applied is provided between the throttle valve 3 and the intake valve 4. .. The fuel supply device 5 inputs sensor signals from various sensors (not shown) that detect operating conditions and operating states, performs arithmetic processing based on the input signals, and outputs a drive signal to the fuel supply device 5 as a result of the processing. .. Further, an assist air passage 8 that bypasses the throttle valve 3 and supplies air from the upstream side of the throttle valve 3 to the downstream side of the throttle valve 3 is formed.

A first embodiment of this fuel supply system is shown in FIGS. 1 and 3 to 5. As shown in FIG. 3, the electromagnetically-operated fuel injection valve 61 is attached to a delivery pipe 62 for supplying fuel to each cylinder of the internal combustion engine. A housing 63 of the fuel injection valve 61 has a stepped tubular shape, and a large diameter portion of the housing 63 has an electromagnetic coil 65 wound around a spool 64. A cylindrical iron core 66 is provided so as to penetrate the spool 64 from above, and an adjusting pipe 67 is provided inside the iron core 66.

A spacer 69 is provided on the small diameter portion of the housing 63.
The nozzle body 10 is superposed and fixed via the nozzle body 10, and an injection hole 12 is formed in an end surface of the nozzle body 10 which projects downward. A needle valve 14 is provided in the nozzle body 10 so as to be slidable from above, and a pintle 16 is formed at the tip of the needle valve 14. The pintle 16 penetrates the inner peripheral wall of the injection hole 12 through a gap. However, it projects from the injection hole 12. Further, a stopper 18 is formed in the substantially center of the needle valve 14 so as to face the spacer 69. Further, the movable core 20 is continuously provided at the upper end of the needle valve 14 so as to face the iron core 66, and the movable core 20 is biased downward by a coil spring 22 arranged between the iron core 66 and the adjusting pipe 67. There is. A sleeve 24 and an annular recess 26 are provided at the end of the nozzle body 10 where the injection hole 12 is formed so as to surround the end of the nozzle body 10.

The detailed structure of the sleeve 24 is, as shown in FIGS. 1 and 4, two fuel injection holes in which the hole diameter decreases conically from the annular recess 26 toward the other end toward the other end. 28 and 30 are formed. An annular skirt 32 protruding downward is formed on the lower portion of the sleeve 24 shown in FIG. A guide passage 34 is formed inside the skirt 32 for guiding fuel and assist air.

As shown in FIG. 3, the passage of the fuel introduced from the fuel intake port 620 inside the delivery pipe 62 is
It is formed between the first O-ring 58 and the second O-ring 59. Air passage 621 formed in the delivery pipe 62
From the second O 2 via the passage 622.
It is supported radially between the ring 59 and the third O-ring 60.

As shown in FIG. 1, two fuel injection holes 2 are provided.
Six air injection holes 40, 42, 44, 46, 48 and 50 are provided around the sleeve axis center O around the circumferences of 8 and 30 by 60 °.
They are evenly formed at intervals. Among these, one of the air injection holes 40 and 42 for atomization control is located above the line segment connecting the sleeve axis center O and the center of the fuel injection hole 28 with a line segment at an angle of 30 ° on both sides around the sleeve axis center O. Is formed in.
The other air atomizing holes 46 and 48 for atomization control are formed on the line segment connecting the sleeve axis center O and the center of the fuel injection hole 30 on both sides of the sleeve axis center O at an angle of 30 °. ing. Then, the air injection holes 44, 50 for controlling the direction
Are formed on a line segment perpendicular to the line segment connecting the centers of the fuel injection hole 28 and the fuel injection hole 30.

Air injection holes 40, 42, 46 for atomization control,
The assist air injected from the fuel injection port 48 is supplied to the fuel injection holes 28, 3 and 3.
It works so as to press the fuel injected from 0 to the center side. On the other hand, the assist air injected from the direction control air injection holes 44 and 50 acts to control the direction of the fuel injected from the fuel injection holes 28 and 30. The angle α formed by the line segment connecting the centers of the air injection holes 40 and 42 for atomization control and the center O of the sleeve axis and the line segment connecting the fuel injection holes 28 and 30 is set to α = 30 °. .. This is because the direction of the fuel spray cannot be controlled if α> 30 °.
In the present invention, the range of α ≦ 30 ° is desirable.

As shown in FIG. 4, the relationship between the hole length L of the air injection hole 50 and the hole diameter d is set to L ≧ 3d. This is L
If <3d, the directionality of the assist air injected from the air injection hole 50 is weakened, and the directivity of the fuel spray is reduced. The angle β formed by the central axis of the air injection hole 50 and the sleeve axis m is set to 30 ° ≦ β ≦ 45 °. this is,
This is because when the angle β <30 °, the atomization of the fuel is reduced, and when β> 45 °, the fuel injected from the fuel injection holes 28 or 30 is blown off and the skirt 32 is blown.
This is because it adheres to the inner wall 321 and causes dripping.

Each air injection hole 40, 42, 44, 46, 4
The relationship between the radius R of the opening end center 501 of the air injection hole 50, which represents the center of the opening end of Nos. 8 and 50, the axial length S of the skirt 32, and the angle β is set to S <R / tan β. This means that if the skirt length S ≧ R / tan β, the fuel spray obtained by the assist air colliding with the fuel injected from the fuel injection holes 28 and 30 adheres to the skirt inner wall 321 and causes drooling. Because it will be.

According to the first embodiment, as shown in FIG. 5A, the fuel injected from the fuel injection holes 28, 30 and the air injection holes 40, 42, 44, 46, 4 at the time of air assist.
Fuel spray is formed on the sleeve shaft center side by the assist air injected from Nos. 8 and 50. As a result, both the atomizing control air injection holes and the direction control air injection holes form a fuel spray with a good spray angle and atomization. On the other hand, in the comparative example shown in FIG. 5B, the air injection holes 401, 4 are added to the fuel injected from the fuel injection holes 28, 30.
When the assist air is injected from 61, the fuel spray shape spreads to both sides as shown in the figure, and the fuel spray shape cannot be pressed toward the sleeve shaft center side.

According to the first embodiment, for example, at the time of cold start of the internal combustion engine, assist air is supplied to the fuel injected from the two fuel injection holes 28 and 30 for atomization control air injection. The assist air from the holes 40, 42, 46, 48 and the air injection holes 44, 50 for controlling the direction collide with the fuel on the front side of the skirt 32, whereby atomization of the fuel and a proper narrow spray angle are obtained. , Improves fuel spray characteristics.

The assist air is cut off when the internal combustion engine has a medium or high load. As a result, the two fuel injection holes 2
The fuel injected from Nos. 8 and 30 is injected toward each intake valve corresponding to each other one by one. Next, the value of the hole diameter d of the air injection hole 50 in the first embodiment of the present invention is d = 1.
3 (mm) fuel supply device A and d in the first embodiment
= 0.74 (mm) Fuel Supply Device B and Actual Flat Flat 1-6
FIG. 6 shows the relationship between the atmospheric pressure around the fuel injection hole and the average particle size of the fuel in the fuel supply device C shown in Japanese Patent No. 1461 and the conventional fuel supply devices D and E without air assist.

As shown in FIG. 6, in the fuel supply systems A and B according to the first embodiment of the present invention, fuel spray having a small average particle size can be obtained when the atmospheric pressure is low, for example, during idling. I understand. On the other hand, in the conventional fuel supply devices C, D and E, the average particle size of the fuel is relatively large. Next, FIG. 7 shows the relationship between the fuel particle size and the fuel weight ratio in the first embodiment A and B of the present invention and the fuel injection device C disclosed in Japanese Patent Laid-Open No. 1-61461.

As shown in FIG. 7, in the fuel supply devices A and B of the first embodiment of the present invention, the average particle size of the fuel is smaller than that of the conventional fuel supply device C, and the fuel of small diameter is used. It can be seen that the weight ratio is high. Next, FIG. 8 shows the relationship between the elapsed time after the cold start and the generation concentration of the unburned HC gas and the vehicle speed in the cold start in the specific operation mode of the vehicle equipped with the internal combustion engine.

As shown in FIG. 8, according to the fuel injection devices A and B according to the first embodiment of the present invention, it is understood that the unburned HC gas generation concentration is particularly low after the start as compared with the conventional example D. Next, FIG. 9 shows the relationship between the average particle size of fuel and the reduction rate of unburned HC gas in the operation mode in the first embodiment of the present invention. It can be seen that in Comparative Example D, which is a comparative example, the reduction rate of unburned HC gas is not improved. On the other hand, in the first and second embodiments, unburned H
It can be seen that the reduction rate of C gas is considerably large.

Further, a sleeve having a fuel injection hole and an air injection hole according to the second embodiment of the present invention is shown in FIGS.
Shown in 1. In the second embodiment, instead of the air injection holes 40, 42, 46, 48 according to the first embodiment, the opening positions of the atomization injection holes 401, 421, 461, 481 for atomization control are relatively sleeved. In this example, the air injection holes 441 and 501 for directional control are also radially outward from the center position O, and are similarly opened relatively outward from the sleeve center position O.

According to the second embodiment, the air injection holes 401, 421, 441, 461, 481, 501 for the fuel injected from the fuel injection holes 28, 30 during the air assist.
Assist air from is collided from the skirt 32 at a relatively lower position. Further, a third embodiment showing a modification of the sleeve according to the third embodiment of the present invention is shown in FIGS. 12 and 13.
Shown in.

The third embodiment is a split type sleeve 24.
This is an example using 1,242. The upper sleeve 241 and the lower sleeve 242 are fitted to each other, and the air injection holes 402, 422, 442, 46 as air assist passages are formed on the mating surfaces thereof.
2, 482 and 502 are formed. According to the third embodiment, the sleeves are the upper sleeve 241 and the lower sleeve 2.
Since it is composed of 42, the assist air passage can be easily formed. In addition, the upper sleeve 241 and the lower sleeve 24
Since the two are joined at the annular welded portion 244 by ultrasonic welding, there is an effect that they can be easily combined and joined.

Next, FIG. 14 shows a modification of the shape of the air injection hole according to the fourth embodiment of the present invention. The fourth embodiment shown in FIG. 14 is an example in which the air injection holes 403 and 463 for atomization control are formed in an arcuate flat shape outside the fuel injection holes 28 and 30, respectively. Since the spray shape of the fuel injected from the fuel injection holes 28 and 30 is regulated so as to be pushed toward the sleeve center side, the excessive spread of the fuel spray is prevented, the injection angle becomes narrow and the atomization is promoted. .. Further, the direction control air injection holes 443 and 503 are the same as the fuel injection holes 28 and 30.
Is provided on a line segment n perpendicular to the line segment connecting the centers of the.
The direction control air injection holes 443 and 503 are similar in shape to the atomization control air injection holes 403 and 463, but their positions are different.

Next, a modification of the fuel injection device according to the fifth embodiment of the present invention is shown in FIG. The fuel injection device according to the fifth embodiment shown in FIG. 15 is an example in which three fuel injection holes are formed. That is, 120 around the center of the sleeve 246.
Atomization control air holes 404, 405, 406, 4 around the fuel injection holes 281, 282, 283 provided at intervals.
07, 408, and 409 are formed. Further, the air injection holes 504, 505, 506 for controlling the direction are provided with the fuel injection holes 281 and 2
82, between 282 and 283, and between 283 and 281. In the fifth embodiment, the atomization of fuel and the spray angle can be controlled from three directions.

Although the present invention has been described with reference to the embodiments in which the number of fuel injection holes is two and three, the present invention can also be applied to a fuel injection device having four or more fuel injection holes. Further, the number of air injection holes is not limited.

[0029]

As described above, according to the fuel supply system for an internal combustion engine of the present invention, the assist air collides with the fuel injected in front of the fuel injection hole formed in the sleeve and is mixed. Therefore, there is an effect that it is possible to form a spray having good fuel spray characteristics without being affected by the pressure difference between the pressure on the fuel downstream side of the fuel injection valve and the pressure inside the fuel injection valve.

Further, when the air assist is performed, a narrow spray angle of the fuel can be obtained, and the fuel having a fine particle diameter can be obtained, so that the fuel spray can be formed well, the fuel consumption rate, the exhaust characteristic and the internal combustion can be improved. The effect is that the output of the engine can be improved.

[Brief description of drawings]

FIG. 1 is a plan view of a sleeve according to a first exemplary embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a mounting position of the fuel supply device according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a mounting position of the fuel supply device according to the first embodiment of the present invention.

FIG. 4 shows a sleeve according to a first embodiment of the present invention.
10 is a sectional view taken along line I-O-II of FIG.

FIG. 5A is an explanatory diagram showing a fuel spray shape of the fuel supply device according to the first embodiment of the present invention, and FIG. 5B is an explanatory view showing a fuel spray shape according to a comparative example.

FIG. 6 is a characteristic diagram showing the relationship between the atmospheric pressure and the average particle size of fuel in the first example of the present invention and the conventional example.

FIG. 7 is a characteristic diagram showing the relationship between the particle size of fuel and the ratio of fuel weight.

FIG. 8 is a characteristic diagram showing an unburned HC gas concentration in a specific operation mode.

FIG. 9 is a characteristic diagram showing the relationship between the average particle size of fuel and the reduction rate of unburned HC gas.

FIG. 10 is a plan view of a sleeve according to a second embodiment of the present invention.

11 is a sectional view taken along line III-O-IV shown in FIG.

FIG. 12 is a plan view of a sleeve according to a third embodiment of the present invention.

13 is a cross-sectional view taken along line V-O-VI shown in FIG.

FIG. 14 is a plan view showing a sleeve according to a fourth embodiment of the present invention.

FIG. 15 is a plan view showing a sleeve according to a fifth embodiment of the present invention.

[Explanation of symbols]

2 intake pipe (intake passage) 12 injection hole 24 sleeve 28, 30 fuel injection hole 32 skirt 40, 42, 46, 48 atomization control air injection hole (air injection hole) 44, 50 direction control air injection hole (air) Injection hole) 61 Fuel injection valve

Claims (1)

[Claims] 1. A fuel injection valve having an injection hole for injecting and supplying fuel toward an intake passage of an internal combustion engine, a plurality of fuel injection holes for circulating the fuel injected from the injection hole, and the plurality of fuel injection holes. A plurality of air injection holes for colliding assist air with fuel injected from the sleeve, and a sleeve having a plurality of fuel injection holes and a skirt for guiding fuel and assist air injected from the plurality of air injection holes to the intake passage The plurality of air injection holes are located on a concentric circle of the sleeve center so as to surround the plurality of fuel injection holes, and atomization that promotes atomization of fuel injected from the fuel injection holes. A control air injection hole and a direction control air injection hole for controlling the direction of the fuel injected from the fuel injection hole, and the axial end of the skirt has an extension line of the fuel injection hole and the air injection hole. A fuel supply device for an internal combustion engine, wherein the fuel supply device is set at an axial position on the fuel injection valve side with respect to a collision position with an extension line of a hole.