JP2896009B2 - Air assist fuel injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-assisted fuel injection device, and more particularly to an air-assisted fuel injection device for injecting fuel into, for example, an automobile engine.

[0002]

2. Description of the Related Art Conventionally, as a fuel injection device for injecting fuel into an air intake pipe of an automobile engine, fuel injection from an injection port is atomized, or fuel attached to the injection port is blown off or the injection port is cooled. 2. Description of the Related Art An air-assisted fuel injection device that uses air for the purpose is known. One example of a conventional air-assisted fuel injection device using assist air for the purpose of atomizing the fuel injected from the nozzle is disclosed in Japanese Utility Model Laid-Open No. 17276/1991.

The air-assisted injector disclosed in Japanese Utility Model Laid-Open Publication No. 3-17276 has the configuration shown in FIG. That is, in FIG. 4, reference numeral 1 denotes an injector for fuel injection, reference numeral 2 denotes an injection port formed at a tip end of the injector 1, reference numeral 3 denotes a body portion having a fuel flow passage 4 formed inside the injector 1, and reference numeral 5 denotes this body portion. An axially movable needle 6 coaxially disposed within the fuel flow passage 4 of the fuel injector 3 is provided at the tip of the needle 5, and the injector 1
The pintles protrude outside from the injection port 2 and diffuse the fuel injected from the injection port 2, respectively.

[0004] A cap 7 is coaxially fitted and fixed to the tip of the body 3, and an assist air passage 8 is formed in the cap 7. The air outlet 9 of the assist air passage 8 is connected to a throttle 11 formed at a substantially middle portion of the chimney 10 formed in the cap 7 in the axial direction.
Are formed in a direction facing the direction.

[0005] In the conventional air-assisted injector device constructed as described above, the valve portion 12 is opened by the rise of the needle 5, and the fuel supplied through the fuel flow passage 4 in the body portion 3 is injected from the injection port 2. Is done. At this time, assist air is blown out of the air outlet 9 in a direction opposite to the injected fuel, and collides with the injected fuel, whereby the fuel is atomized.

[0006]

However, in the above-described conventional air-assisted injector, the air outlet 9 of the assist air is located considerably downstream of the tip of the pintle 6. Therefore, the assist air blown out from the air outlet 9 collides with the fuel injected from the injection port 2 and diffused by the pintle 6 in the space in the chimney portion 10 downstream of the pintle 6, so that the injection is performed. Although the atomization of the fuel is certainly improved compared to the conventional one, it cannot be said that the efficiency (the ratio of the amount of air used for achieving the same atomization state, that is, the smaller the amount of air is, the higher the efficiency) is. .

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the conventional air-assisted fuel injection system, and it is an object of the present invention to provide assist air in a fuel injection system of a type in which fuel injected from an injection port is diffused by a pintle. It is another object of the present invention to provide an air-assisted fuel injection device that further promotes atomization of fuel by the method and further improves the efficiency.

[0008]

SUMMARY OF THE INVENTION An air-assisted fuel injection device according to the present invention is an injection device having an axially movable needle housed in a nozzle body and a pintle provided at a tip of the needle and projecting from an injection port of the nozzle body. A valve, an assist air outlet provided in the vicinity of the pintle on the upstream side of the tip of the pintle, and blowing assist air to the pintle in a direction opposite to the fuel injection direction injected from the injection port and at an intersection angle. Is characterized by including.

[0009]

According to the air assist fuel injection device of the present invention,
When the needle rises, fuel is injected and diffused from the injection port along the pintle. At this time, air is blown from the assist air outlet provided on the upstream side of the tip of the pintle and in the vicinity of the pintle in the opposite direction to the fuel flow injected from the nozzle at an intersection angle. As a result, the assist air immediately collides with the fuel with the fastest flow velocity immediately below the nozzle, so that the impact force due to the collision is large and the fuel is atomized. Further, the air blown out from the assist air outlet also collides with the pintle, and blows off the fuel that flows down or adheres to the thin film along the peripheral surface of the pintle, thereby promoting further atomization.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The air-assisted fuel injection device of the present invention will be described in more detail below with reference to an embodiment shown in the drawings. FIG.
2 and FIG. 2 show an air-assisted fuel injection device 20 according to one embodiment of the present invention. The air-assisted fuel injection device 20 of this embodiment includes an injection valve (corresponding to the injector 1 shown in FIG. 4) 21 as in the prior art, and the injection valve 21 has an injection port 22 at a distal end and a fuel flow passage (inside). (Not shown).

An axially movable needle 24 is coaxially arranged in the fuel flow passage in the body 23. At the tip of the needle 24, a pintle 25 similar to the conventional one is formed, which protrudes outside from the injection port 22 of the body 23 and diffuses the fuel injected from the injection port 22. A plate 26 is disposed on the tip end surface of the body 23 in which the nozzle 22 is formed.

As shown in FIGS. 2 and 3, the plate 26 has a thickness smaller than the distance from the injection port 22 to the tip 25a of the pintle 25, and has a cross-shaped opening 27 formed at the center. The pintle 25 passes through the intersection of the cross-shaped opening 27 and protrudes downward.
The injection valve 2 having the plate 26 disposed on the tip surface in this manner.
An adapter 28 is fitted and mounted on the first trunk 23.

The adapter 28 has a cap shape, and is mounted so that the body 23 of the injection valve 21 is relatively fitted into a concave portion 28a having an open upper end. Adapter 28
At the bottom of the concave portion 28a, a projection 29 having a frustoconical shape with the center axis of the adapter 28 as an axis is formed.
Further, an opening is formed at the bottom of the concave portion 28a of the adapter 28 from the center of the upper end of the projection 29 outward in the axial direction, and the opening has a chimney portion 30 whose diameter increases as going outward. Have been.

As shown in FIG. 3, the inner diameter of the concave portion 28a of the adapter 28 is substantially equal to the outer diameter of the plate 26, and grooves 31 for introducing assist air are formed on the inner wall thereof on all sides.
The recess 28a extends from the upper end to the bottom. Plate 2
The size of the center intersection of the cross-shaped opening 27 formed at the center of the projection 6 is substantially equal to the inner diameter of the upper end opening of the projection 29, and therefore the corner of the intersection of the cross-shaped opening 27 is the upper end surface of the projection 29. This causes the plate 26 to form a space 32 between itself and the bottom thereof in the adapter 28 and to be placed and supported on the projection 29 while the tip of the pintle 25 is formed by the cross-shaped opening 27 of the plate 26. It passes through the intersection and enters the chimney 30 from the upper end of the projection 29.

Cross-shaped opening 2 formed in plate 26
7, the length of each opening extending radially outward from the intersection center is longer than the outer diameter of the upper end of the projection 29, thereby extending radially outward beyond the upper end of the projection 29. An opening extending from the space portion 32 is formed as an assist air outlet 33 extending from the space portion 32 to the center of the cross-shaped opening 27, that is, the intersection. Therefore, the assist air 34 introduced into the space 32 through the groove 31 is directed obliquely upward by the inclined surface 29 a of the projection 29, as is clear from FIG. From the outlet 33 in the opposite direction and at an intersection angle
Sprayed towards.

The assist air is sent into the case 35 from an air introduction path 36 provided in a case 35 hermetically fitted to the outer peripheral portion of the adapter 28,
Of the plate 26 and the adapter 28 from the top of the
Into the space 32 between the bottom of the recess 28a. Then, as described above, the fuel is blown from the outlet 33 toward the pintle 25 in a direction opposite to the spray direction of the fuel and at an intersection angle very close to the pintle 25.

Next, the operation of the air-assisted fuel injection device 10 of the embodiment configured as described above will be described. When the needle 24 is raised by an electromagnetic solenoid (not shown), fuel is injected from the injection port 22 along the pintle 25 as shown by a dotted arrow 37 in FIG.
8 at the chimney portion 30. At this time, the assist air 34 is blown from the assist air outlet 33 provided in the vicinity of the pintle 25 to the injected fuel flow 37 in the opposite direction to the injected fuel flow 37 from the injection port 22 and at an intersection angle.

As a result, the assist air 34 is
Since the fuel collides with the fuel having the highest flow velocity immediately below the fuel cell 2, the impact force due to the collision is large, and the fuel is effectively atomized. At the same time, the air 34 blown out from the assist air outlet 33 collides with the pintle 25, and blows off the fuel that flows down or adheres to the thin film along the peripheral surface of the pintle 25 and atomizes it.

By forming the assist air outlet 33 in the vicinity of the side of the pintle 25 in the opposite direction to the fuel flow injected from the injection port 22 at a crossing angle, the atomization is effectively performed. Therefore, desired atomization can be achieved with a small amount of air, and the efficiency of atomization can be significantly improved.

In the above-described embodiment, the opening 27 formed in the plate 26 is formed in a cross shape. However, the present invention is not limited to this, and a plurality of holes 27 are provided around the pintle insertion hole. An opening that extends in the radial direction may be formed.

[0021]

As described above, according to the air-assisted fuel injection system of the present invention, the assist air outlet which blows out the fuel flow from the injection port in the opposite direction and at an intersection angle is provided at the side of the pintle. By providing it near,
The atomization of the fuel can be further promoted and the efficiency can be further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view partially showing an air-assisted fuel injection device according to one embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the air-assisted fuel injection device shown in FIG.

FIG. 3 is a cross-sectional view of the air-assisted fuel injection device taken along the line III-III in FIG. 1;

FIG. 4 is a sectional view showing a conventional air-assisted fuel injection device.

[Explanation of symbols]

 Reference Signs List 20 air-assisted fuel injection device 21 injection valve 22 injection port 23 trunk 24 needle 25 pintle 26 plate 27 opening 28 adapter 29 protrusion 30 chimney 33 assist air outlet

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Mamoru Sumita 840 Chiyoda-cho, Himeji-shi, Hyogo Mitsubishi Electric Corporation Himeji Works (72) Inventor Kazuyoshi Yamamoto 840 Chiyoda-cho, Himeji-shi, Hyogo Mitsubishi Electric Corporation Himeji Works (56) References JP-A-62-182475 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02M 69/04 F02M 69/00 310

Claims (1)

(57) [Claims] 1. An injection valve having an axially movable needle housed in a nozzle body, and a pintle provided at a tip of the needle and projecting from an injection port of the nozzle body, and an injection valve of the pintle upstream of the tip of the pintle. An air assist fuel injection device, which is provided in the vicinity and includes an assist air outlet that blows assist air to the pintle at a crossing angle in a direction opposite to a fuel injection direction injected from the injection port.