JPH09280139A - Fuel injection valve of variable injection angle type - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a good atomized state by adjusting an injection angle in a wide range. SOLUTION: A fuel injection valve V has a fuel passage 10 communicating with an injection port 11 and a plurality of air passages 12, 13 communicating with the fuel passage 10 near the injection port 11. The entire pressure which air sent into the fuel passage 10 from the air passages 12, 13 affects the fuel in the fuel passage 10 at the openings 14, 15 of the air passages 12, 13 is changed by changing the whole area of the openings 14, 15 of the air passages 12, 13 for the fuel passage 10 or by changing the air pressure in the air passages 12, 13. Therefore the injection angle β of the fuel injected from the injection port 11 can be changed by the air from the air passages 12, 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to means for changing an injection angle in a fuel injection valve of an internal combustion engine.

[0002]

2. Description of the Related Art In a conventional fuel injection device disclosed in Japanese Patent Laid-Open No. 7-119590, as shown in FIG. 1 of the publication, one air is provided in one fuel supply passage 51 or 50 (injection portion). The supply passages 53 or 52 communicate with each other at an acute predetermined intersection angle, and the injection angle of the fuel injected from the fuel supply passages 51 or 50 (injection portion) is changed by the air from the air supply passages 53 or 52. be able to.

[0003]

However, only one air supply passage 53 or 52 intersects one fuel supply passage 51 or 50 (injection portion) and the positional relationship between them is constant. It becomes difficult to change the air force that the injected fuel receives from the air supply passage 53 or 52 to a wide range, and the direction in which the spray region is inclined and the injection angle are limited.

The object of the present invention is to make it possible to adjust the direction in which the spray area is inclined and the injection angle in a wide range.

[0005]

A fuel injection valve according to the present invention has a fuel passage communicating with an injection port and an air passage communicating with the fuel passage near the injection port. In particular, a plurality of the air passages are provided, and air force changing means for changing the total pressure exerted on the fuel in the fuel passages by the air sent out from the air passages to the fuel passages at the openings of the air passages with respect to the fuel passages is provided. ing. Therefore, the injection angle of the fuel injected from this injection port can be changed by the air from this air passage.

[0006]

DETAILED DESCRIPTION OF THE INVENTION A fuel injection valve according to an embodiment of the present invention will be described below with reference to the drawings. [Regarding Configuration of Fuel Injection Valve V Equipped with Injection Angle Changing Means] The fuel injection valve V includes a nozzle body 1 and an adapter 2 to which a tip end portion is detachably fitted. The illustration and description of other components of the fuel injection valve V are omitted.

A needle valve body 3 is provided in the nozzle body 1.
Are slidably fitted. A sac hole 4 and a communication hole 5 continuous with the sac hole 4 are formed at the center of the tip of the nozzle body 1 on the axis 3a of the needle valve body 3, and the nozzle body 1 is provided on the inner peripheral side of the sac hole 4. A valve seat portion 6 is formed on the inner bottom portion of the. The seat surface 7 formed at the tip of the needle valve body 3 is pressed against the valve seat portion 6 of the nozzle body 1 by a valve spring (not shown). A fuel supply passage 8 is formed between the inner peripheral surface of the nozzle body 1 and the outer peripheral surface of the needle valve body 3, and communicates with the suck hole 4 via the valve seat portion 6. The adapter 2
A communication hole 9 is formed therein, and is linearly connected to the communication hole 5 of the nozzle body 1 on the axis 3a of the needle valve body 3. The fuel passage 10 is composed of the fuel supply passage 8, the suck hole 4, the communication hole 5 and the communication hole 9, and one injection port 11 is formed at the outer end of one communication hole 9. In the fuel passage 10, the needle valve body 3 is connected to the valve seat portion 6
On the other hand, the valve spring (not shown) presses the valve spring (not shown) to close the valve, and the needle valve body 3 is opened by the electromagnetic force of the solenoid (not shown) against the elastic force of the valve spring. .

(Details of Injection Angle Changing Means) In the adapter 2, two air passages 12 and 13 are arranged in the vicinity of the injection port 11 which communicates with the communication hole 9 of the fuel passage 10.
The openings 14, 15 of the air passages 12, 13 are provided on both sides of the communication hole 9 at a point symmetry position of 180 degrees about the extension center line 9a of the communication hole 9 on the axis 3a of the needle valve body 3. Is formed and opened to the communication hole 9. The communication hole 9 and the air passages 12 and 13 are respectively provided with the extension center line 9
Inner diameters D ₉ , D ₁₂ , D ₁₃ centered on a, 12a, 13a
It has a circular cross section. The extension center lines 12a and 13a of the air passages 12 and 13 are inclined toward the injection port 11 side, and an acute intersection angle θ with respect to the extension center line 9a of the communication hole 9 is formed.
They intersect at ₁₂ and θ ₁₃ (θ ₁₂ = θ ₁₃ ). These intersections are on the extension center line 9a of the communication hole 9 near the injection port 11. The injection port 11 has a circular cross-section with an inner diameter D ₁₁ (D ₁₁ = D ₉ ) centered on the extension center line 9 a of the communication hole 9.

Inner diameters D ₁₂ , D of the air passages 12, 13
By changing ₁₃ (D ₁₂ <D ₁₃ ) and setting the total areas A ₁₂ and A ₁₃ (A ₁₂ <A ₁₃ ) of the openings 14 and 15 to be different, the air force changing means is configured. In that case, the strength of the pressure of the air supplied to the air passages 12 and 13 (pressure degree) is P ₁₂ , P ₁₃ (P ₁₂ = P ₁₃ = P), and the air passages 1 are
2 and 13 through openings 14 and 15 through the fuel passage 10 through hole 9
When the total pressure exerted on the fuel in the communication holes 9 by the air sent to the fuel cells in the openings 14 and 15 is F ₁₂ and F ₁₃ , F ₁₂ =
P × A ₁₂ and F ₁₃ = P × A ₁₃ . Therefore, F ₁₂ <F ₁₃
Becomes

[Outline of the control means of the fuel injection valve V and its fuel injection action] The fuel supply passage 8 of the fuel passage 10 is connected to a fuel tank 16. Each of the air passages 12 and 13 is connected to an air supply circuit 17.
In the air supply circuit 17, air whose pressure intensity (pressure level) is set to P ₁₂ , P ₁₃ (P ₁₂ = P ₁₃ = P) is supplied to the air passages 12, 13. The solenoid (not shown) is connected to the valve opening / closing drive circuit 18 to excite the solenoid based on the valve opening / closing signal. The engine control computer (ECU) uses various detection sensors 19 (for example, an intake air temperature sensor, a throttle sensor, an intake pressure sensor, a combustion pressure sensor, an oxygen concentration sensor, an exhaust temperature sensor, a water temperature sensor, a knock sensor, an engine speed sensor, a crank). The air supply circuit 17, the valve opening / closing drive circuit 18, and the like are drive-controlled based on the detection signal from the angle sensor).

When the solenoid is excited by the drive signal from the ECU based on the valve opening signal from the valve opening / closing drive circuit 18, the seat surface 7 of the needle valve body 3 opens to the valve seat portion 6, and the fuel is discharged. Fuel passage 10 from tank 16
The fuel supplied to is injected from the injection port 11 and spreads in a conical shape. In synchronization with this fuel injection, a drive signal from the ECU causes the air supply circuit 17 to drive each air passage 1
When air is supplied to the nozzles 2 and 13, the communication hole 9 is set to the injection port 11
It collides with the injected fuel toward. In this case, as described above, since the total pressure F ₁₃ of the air passage 13 side is larger than the total pressure F ₁₂ of the air passage 12 side, air force the injected fuel undergoes the air passage 12 side in this air passage 13 side Will be larger than. Therefore, the spray area that spreads in a conical shape (its spread angle) is inclined toward the air passage 12 side, and the extension center line 9 of the communication hole 9 is formed.
The central axis of the spray angle α (spread angle of the spray region) forms the spray angle β with respect to the extending center line 11a of the spray port 11 located on a.

The inner diameter of each air passage 12, 13
D₁₂, D₁₃Total area A of openings 14 and 15₁₂, A₁₃And cross
Angle θ₁₂, Θ₁₃Is replaced with a different adapter 2 or each empty
Pressure P of air supplied to the air passages 12 and 13₁₂,
P₁₃To P₁₂= P₁₃= P or change under the condition
Pressure strength P₁₂, P₁₃Set to different from each other
If so, the injected fuel is received from each of the air passages 12 and 13.
Air force (total pressure F ₁₂, F₁₃) Can be changed
You.

The present embodiment has the following characteristics (a) to (d) (other than other technical ideas described later). (A) The air sent out from the two air passages 12, 13 to the fuel passage 10 is the air passage 1 for the fuel passage 10.
Air force changing means for changing the total pressures F ₁₂ , F ₁₃ exerted on the fuel in the fuel passage 10 at the openings 14, 15 of 2, ₁₃ are provided. Therefore, the spray angle α, the spray region inclination direction (the central axis direction of the spray angle α), and the injection angle β can be adjusted in a wide range according to the respective air forces (total pressures F ₁₂ , F ₁₃ ).

For example, in a fuel injection valve that directly injects fuel into a cylinder, in the technique relating to "stratified combustion", the fuel is divided into an intake stroke and a compression stroke during a relatively low load operation in which the fuel injection amount is small. By injecting, the fuel injected during the intake stroke forms a homogeneous lean mixture capable of flame propagation throughout the cylinder, and the fuel injected during the compression stroke (at least part of the required fuel injection amount) A stratified state is formed in the vicinity of the spark plug to form a relatively rich air-fuel mixture that can be ignited, and a lean air-fuel mixture combustion is performed.
Therefore, the ignition of the air-fuel mixture and the propagation of the flame become good,
The combustion state is improved. In such stratified combustion, if the injection angle β of the fuel injection valve V can be adjusted in a wide range, it is effective in the case of injecting fuel toward the piston head in the intake stroke and the compression stroke. Further, if the injection angle β of the fuel injection valve V can be adjusted in a wide range, it is also effective when the fuel is injected into a plurality of intake ports by one fuel injection valve V.

(B) Conventionally, when the fuel injection valve is mounted on the engine while avoiding interference with the intake manifold,
The extending center line of the injection port is inclined with respect to the axis of the needle valve body so that the injection port faces the piston head. In that case, if the injection port is formed by eccentricity with respect to the right conical tip of the nozzle body, the inner and outer edges of the injection port will be deformed into a circular shape, and the fuel distribution will be non-uniform when passing through the fuel. It has a bad influence on the spray state. Therefore, it is desirable that the extension center line of the injection port be aligned with the axial center line of the needle valve body.

In view of this point, in the present embodiment, the communicating holes 5 and 9 and the injection port 1 with respect to the axial center line 3a of the needle valve body 3 are provided.
1 extending center lines 5a, 9a, 11a are aligned with each other,
The shape of the outer edge of the injection port 11 is close to a perfect circle. Therefore, it is possible to maintain a uniform spray and obtain a good spray state. Even in that case, since the injection angle β of the fuel injection valve V can be adjusted in a wide range, it becomes possible to inject the fuel toward the piston head.

(C) As described above, the ECU
The strength P of the pressure of the air supplied to each air passage 12, 13
By controlling ₁₂ and P ₁₃ , the injection angle β can be set according to the operating condition.

(D) In the air-assist type fuel injection valve V as in the above embodiment, the swirl collar for giving a swirl flow to the fuel can be omitted in the fuel supply passage 8 on the outer periphery of the needle valve element 3. .

[Other Embodiments] Besides the above embodiment, the following (a) to (b) may be adopted. (B) Provide three or more air passages. Furthermore, it is not necessary to provide these air passages at point symmetrical positions around the extending center line 9a of the communication hole 9, and various circumferential angles may be set between the air passages. Further, the air passages do not have to intersect at one place.

(B) The extending center line 11a of the injection port 11 is inclined with respect to the extending center line 9a of the communication hole 9. [Other technical ideas] The technical ideas (other than the claims) that can be grasped from each embodiment are described together with the effects.

(A) In claim 1, the air force F₁₂,
F₁₃The means for changing (total pressure) is for the fuel passage 10.
Total area of openings 14 and 15 of each air passage 12 and 13
A₁₂, A ₁₃Is set to a different one. Follow
Thus, the injection angle β can be adjusted in a wide range.

(B) In claim 1, the air force F ₁₂ ,
The means for changing F ₁₃ (total pressure) is the pressure intensity P ₁₂ of the air in each of the air passages 12 and 13 with respect to the fuel passage 10.
₁₃ (Pressure) is set to different values. Therefore, the injection angle β can be adjusted in a wide range.

(C) In claim 1, the air force F₁₂,
F₁₃The means for changing (total pressure) is for the fuel passage 10.
Total area of openings 14 and 15 of each air passage 12 and 13
A₁₂, A ₁₃The fuel passage
The strength of the pressure of the air in each air passage 12, 13 with respect to 10
Sa P₁₂, P₁₃With a configuration in which (pressure) is set to different
is there.

(D) In Claim 1, the above (a), the above (b) or the above (c), a valve body 3 for opening and closing the fuel passage 10 is provided, and injection is performed with respect to the axial center line 3a of the valve body 3. The extension center lines 11a of the mouths 11 are aligned with each other. Therefore, it is possible to maintain a uniform spray and obtain a good spray state.

[0025]

According to the fuel injection valve of the present invention, the injection angle can be adjusted over a wide range, and thus a good spray state can be obtained.

[Brief description of drawings]

1A is a partial cross-sectional view showing a nozzle of a fuel injection valve according to the present embodiment, and FIG. 1B is a schematic view showing a circuit for driving and controlling the fuel injection valve of FIG.

[Explanation of symbols]

10 ... Fuel passage, 11 ... Injection port, 12, 13 ... Air passage, 14, 15 ... Opening, V ... Fuel injection valve, β ... Injection angle.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location F02M 69/00 310 F02M 69/00 310E

Claims (1)

[Claims] 1. A fuel passage communicating with an injection port, and an air passage communicating with the fuel passage in the vicinity of the injection port. The injection angle of fuel injected from the injection port is determined by the air from the air passage. In the fuel injection valve that can be changed by a plurality of air passages, the total pressure exerted on the fuel in the fuel passage by the air sent from these air passages to the fuel passage at the opening of each air passage to the fuel passage is A variable-injection-angle variable-type fuel injection valve provided with a changing air force changing means.