WO1999004159A1

WO1999004159A1 - Fuel injection nozzle

Info

Publication number: WO1999004159A1
Application number: PCT/JP1998/003206
Authority: WO
Inventors: Takao Iwasaki; Toshiyuki Hasegawa; Kouji Matsui; Takashi Kobayashi
Original assignee: Zexel Corporation
Priority date: 1997-07-18
Filing date: 1998-07-16
Publication date: 1999-01-28
Also published as: JPH1137016A

Abstract

A fuel injection nozzle, particularly of a Diesel engine and an inter-cylinder type gasoline engine, for providing a swirl that induces a swirl flow of a fuel inside a nozzle hole (13) to increase spread of atomization, promoting mixing of the fuel with air within a short time to improve combustion performance of the engine, and capable of controlling an atomization distribution direction. Characterized in that a swirl flow is induced inside a nozzle hole (13) itself having a nozzle hole inlet (24), a nozzle hole main portion (23) and a nozzle hole outlet (25), the sectional shape of the nozzle hole inlet (24) or the nozzle hole outlet (25) of the nozzle hole (13) is deviated from the axis of the nozzle hole (13), the sectional area of the nozzle hole inlet (24) of the nozzle hole (13) is set to be smaller than the sectional area of the nozzle hole main portion (23) and an open sectional area of the nozzle hole inlet (24) is deviated from an open section of the nozzle hole main portion (23).

Description

細 Details of fuel injection nozzle

The present invention relates to a fuel injection nozzle, and more particularly to a fuel injection nozzle capable of improving a spray shape in a diesel engine or a direct injection type gasoline engine. Background art

In conventional diesel engines and in-cylinder direct injection type gasoline engines, the fuel injection nozzle is a single component, and its injection characteristics and spray characteristics affect engine performance and exhaust gas properties. It is well known that

At present, for example, diesel engines have been improved by using hole nozzles as fuel injection nozzles to increase the injection pressure to a high pressure of 10 OMPa or more. Further improvements in performance and exhaust gas performance are desired.

In particular, in diesel engines, fuel is injected into a combustion chamber under high pressure and high temperature to ignite and burn, so it is necessary for the fuel to reach a predetermined part of the combustion chamber, and the injected fuel is short. It is desirable to mix with air and burn it quickly during the time.

In other words, depending on the spray shape of the injected fuel, how much air can be taken in or mixed with air in a short time will have a great effect on the combustion characteristics. Disclosure of the invention The present invention has been made in view of the above-described problems, and has as its object to provide a fuel injection nozzle capable of mixing injected fuel with air more efficiently.

Further, the present invention provides a fuel injection nozzle capable of providing a spray for inducing a swirl flow in fuel in an injection hole to increase the spread of spray and promote the mixing of fuel and air. The task is to provide

The present invention also provides a fuel injection nozzle that can improve the combustion performance of an engine by promoting the mixing of fuel and air in a short time, particularly in a diesel engine or a direct injection gasoline engine. The task is to provide.

Another object of the present invention is to provide a fuel injection nozzle capable of spraying in an appropriate shape according to the load and the number of revolutions of the engine.

Another object of the present invention is to provide a fuel injection nozzle capable of adding swirl to spray.

Another object of the present invention is to provide a fuel injection nozzle capable of controlling the direction of dispersion of spray.

Further, according to the present invention, depending on the type of engine or the combustion chamber, etc., the dispersion direction of the spray can be biased in a predetermined direction or not, and further, the bias direction can be controlled. It is an object to provide a fuel injection nozzle.

That is, the present invention provides a method for inducing a swirling flow inside an injection hole itself, that is, to be able to give swirl to fuel in the injection hole, and as a structure for this purpose, an injection hole of the injection hole. The first aspect of the invention focuses on making the cross-sectional shape of the inlet or the outlet of the injection hole knitted from the axis of the injection hole. A nozzle body having an injection hole formed therein and a seat surface, and a needle valve slidably provided in the nozzle body and capable of injecting fuel from the injection hole by lifting from the sheet surface. A fuel injection nozzle having a cross-sectional area of the injection hole inlet portion of the injection hole and a cross-sectional area of the injection hole main portion. The fuel injection nozzle is characterized in that the cross section is smaller than the product and the opening cross section of the injection hole inlet is deviated from the opening cross section of the main injection hole.

According to a second aspect of the present invention, there is provided a nozzle body having an injection hole inlet portion, an injection hole main portion and an injection hole outlet portion, a seat surface, and a slidably provided nozzle inside the nozzle body. A fuel injection nozzle having a needle valve capable of injecting fuel from the injection hole by lifting from the sheet surface, wherein a cross-sectional area of the injection hole inlet portion of the injection hole is determined by the injection hole. In addition to making the cross-sectional area smaller than the main portion, the fuel flowing into the injection hole inlet can be introduced from a direction deviated from the axis of the injection hole main portion. This is a characteristic fuel injection nozzle.

When viewed from the axial direction of the injection hole, a part of the periphery of the injection hole entrance portion and a part of the periphery of the injection hole main portion can overlap.

An injection fuel passage intersecting the injection hole is provided inside the injection hole, and an intersection of the injection fuel passage and the injection hole has an injection hole having a cross-sectional area smaller than a cross-sectional area of the injection hole main portion. An inlet can be formed.

The injection hole and the introduction fuel passage intersecting with the injection hole can cross each other at a substantially right angle.

An injection hole variable mechanism that can change the cross-sectional area of the injection hole entrance portion can be provided. A counterbore deviated from the main portion of the injection hole can be provided at the injection hole exit portion.

The counterbore can be biased toward the central axis of the injection hole inlet with respect to the central axis of the injection hole main portion.

Further, a third invention provides a nozzle body having an injection hole inlet portion, an injection hole main portion, and an injection hole outlet portion, a nozzle body having a seat surface, and a slidably provided inside the nozzle body. A fuel injection nozzle having a needle valve capable of injecting fuel from the injection hole by lifting from the sheet surface, wherein the fuel injection nozzle comprises: The fuel that flows into the part is spiraled with respect to the axis of The fuel injection nozzle is characterized by forming a swirl mechanism in the injection hole to flow while turning.

In the fuel injection nozzle according to the present invention, the cross-sectional area of the injection hole inlet portion is made smaller than the cross-sectional area of the injection hole main portion, or the flow path that can generate swirl is formed into a shape in which a streamline is bent Because of the shape, the fuel that is to be injected into the combustion chamber from the injection hole by the lift of the needle valve will flow spirally along the axis of the injection hole through the injection hole. When the fuel is injected from the nozzle, the fuel is injected as a spray expanded to a predetermined range.

Therefore, sprays that are more widespread than conventional fuel injection nozzles can easily take air in the combustion chamber into the interior, that is, improve the mixing ratio with air, and expect good combustion. Can be.

Furthermore, by changing the degree of the swirl according to the load and the number of revolutions of the engine, it is possible to provide an appropriate spray shape or penetration according to each operating condition. Can be.

That is, as an example of the swirl mechanism for controlling the degree of swirl, a variable injection hole mechanism can be adopted, and an appropriate injection amount can be obtained by making the cross-sectional area of the injection hole variable. At the same time, the above-described spray can be obtained, which can further contribute to improving the performance of the engine.

As described above, according to the present invention, swirl is generated by biasing the injection hole inlet portion and the injection hole main portion inside the injection hole, so that the spray shape of the injected fuel has a predetermined spread. It can promote the mixing of fuel air and contribute to good combustion. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram of a fuel injection device 1 having a fuel injection nozzle 3 according to a first embodiment of the present invention. FIG. 2 is an enlarged perspective view of the main part of the nozzle body 8, the injection hole variable mechanism 10 and the swirl mechanism 11 of the fuel injection nozzle 3.

FIG. 3 is a cross-sectional view of the injection hole variable mechanism 10 and the swirl mechanism 11 when the rotary valve 17 is rotatable.

FIG. 4 is a sectional view of the same when the needle valve 9 is lifted.

FIG. 5 is a sectional view taken along line VV of FIG.

FIG. 6 is a cross-sectional view of the same orifice 17 valve and the view from the axial direction of the corresponding injection hole 13 in parallel with the opening degree of each injection hole 13 in the same manner. FIG.

FIG. 7 is an explanatory diagram visualizing the spray shape at the beginning of the injection according to the opening degree of each of the injection holes 13 shown in FIG.

FIG. 8 is a graph showing the relationship between the cam angle and the injection angle.

FIG. 9 is a graph showing the relationship between the cam angle and the penetration at the injection tip.

FIG. 10 is a sectional view taken along line XX of FIG.

FIG. 11 is a view taken in the direction of the arrow XI in FIG.

FIG. 12 is an enlarged sectional view of a main part of a fuel injection nozzle 30 according to a second embodiment of the present invention.

FIG. 13 is a cross-sectional view taken along the line XII I-XII I in FIG.

FIG. 14 is a view in the XIV direction of FIG.

FIG. 15 is a horizontal sectional view of the nozzle hole 13 in the state of FIGS. 10 and 11, a side sectional view of the nozzle hole 13, and an axial view of the nozzle hole 13. FIG. 4 is an explanatory diagram showing the figure in parallel.

FIG. 16 is a horizontal sectional view of the injection hole 13, a side sectional view of the injection hole 13, and an arrow view of the injection hole 13 in the state of FIGS. 12 to 14. FIG. 4 is an explanatory diagram showing the figure in parallel. FIG. 17 shows an example of an oblong counterbore 33 in the same manner. Similar to FIGS. 15 and 16, a horizontal sectional view, a lav sectional view, and an arrow view are shown in parallel. FIG.

FIG. 18 shows an example of a circular counterbore 34 in the same manner as FIG. 15 and FIG. 16, showing a horizontal sectional view, a lav sectional view, and an arrow view in parallel. FIG.

FIG. 19 shows an example of a triangular counterbore 35 in the same manner as FIG. 15 and FIG. 16, with a horizontal sectional view, a side sectional view and an arrow FIG.

FIG. 20 shows an example of a conical counterbore 36 in the same manner as FIG. 15 and FIG. 16, showing a horizontal sectional view, a side sectional view, and an arrow view in parallel. FIG.

FIG. 21 is a cross-sectional view of the tip of a fuel injection nozzle 40 of a conventional general hole nozzle type.

FIG. 22 is a sectional view taken along the line XXII-XXII of FIG.

FIG. 23 is a view as seen in the direction of the arrow XXII in FIG.

FIG. 24 is a horizontal sectional view of the injection hole 13 of the fuel injection nozzle 50 according to the third embodiment of the present invention.

FIG. 25 is an axial view of the injection hole 13 as viewed from the direction of the arrow.

FIG. 26 is an axial view of the injection hole 13 of the fuel injection nozzle 52 according to the fourth embodiment of the present invention.

FIG. 27 is a horizontal sectional view of the injection hole 13 of the fuel injection nozzle 60 according to the fifth embodiment of the present invention.

FIG. 28 is an axial view of the injection hole 13 as viewed from the direction of the arrow.

FIG. 29 is an enlarged sectional view of a main part of a fuel injection nozzle 70 according to a sixth embodiment of the present invention. FIG. 30 is a sectional view taken along the line XXX-XXX in FIG.

FIG. 31 is a view in the direction of the XXXX direction of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Next, a fuel injection nozzle according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic diagram of a fuel injection device 1. The fuel injection device 1 includes a fuel injection pump 2, a fuel injection nozzle 3 according to the present invention, an injection amount sensor 14, and control means δ. Have.

The fuel injection pump 2 pressurizes the fuel from a fuel tank (not shown) and supplies the fuel to a fuel introduction section 6 of a fuel injection nozzle 3.

The fuel injection nozzle 3 includes a nozzle housing 7 having a fuel introduction section 6, a nozzle body 8 attached to the nozzle housing 7, a needle valve 9 that slides back into the nozzle body 8, and a variable injection hole mechanism. 10 and a swirl mechanism 11.

The fuel injection nozzle 3 is a hole nozzle type, has a hole 12 at the tip of the nozzle body 8, and has an injection hole 13 formed in the hole 12.

The control means 5 drives the actuator 14 of the injection hole variable mechanism 10 in response to the fuel pressure detection signal from the injection amount sensor 14, and controls the injection hole variable mechanism 10 of the fuel injection nozzle 3. I do.

FIG. 2 is an enlarged perspective view of a main part of the nozzle body 8, the injection hole variable mechanism 10 and the swirl mechanism 11 of the fuel injection nozzle 3. The injection hole variable mechanism 10 includes the above-mentioned actuator unit. 14, the mouthpiece shaft 15 attached to the factory unit 14, the connecting part 16 attached to the mouthpiece shaft 15, and the mouthpiece attached to the connecting part 16 And one valve 17.

The orifice shaft 15 is inserted into the inside of the needle valve 9 from the top of the nozzle housing 7 to the lower part. The connecting portion 16 connects the mouthpiece shaft 15 and the mouthpiece valve 17 movably (with play) in the axial direction of the rotary shaft 15.

The rotary valve 17 is located at the lower part of the needle valve 9 and has a substantially conical shape capable of engaging with the inside of the hole portion 12, and has a sheet arc portion 1 capable of closing the injection hole 13. 8 and a variable groove portion 19 (introducing fuel passage) between the sheet circular arc portion 18 and communicating with the injection hole 13 (in the example shown, each has a length of 5 mm).

Fig. 3 is a sectional view of the nozzle hole variable mechanism 10 and the scroll mechanism 11 when the rotary valve 17 is rotatable, and Fig. 4 is a sectional view of the same when the 21-dual valve 9 is lifted. In the figure, the seat portion 20 of the dollar valve 9 is seated on the seat surface 21 of the upstream lavatory from the nozzle hole 13 of the nozzle body 8 so that the fuel passage 2 from the fuel introduction portion 6 is formed. 2 and injection hole 13 are shut off.

In addition, if the sheet circular arc portion 18 of the rotary valve 17 is opposed to the injection hole 13, the injection hole 13 is closed, and if the variable groove portion 19 faces the injection hole 13, a dollar valve is provided. The lift 9 allows the fuel passage 22 and the injection hole 13 to communicate with each other through the variable groove 19.

Of course, the opening degree of the injection hole 13 can be changed by the relative position between the variable groove portion 19 and the injection hole 13.

The swirl mechanism 11 can be realized by the above-described injection hole variable mechanism 10 in the fuel injection nozzle 3 according to the first embodiment.

FIG. 5 is a cross-sectional view taken along the line V--V in FIG. 3, and shows the relative position of the variable groove portion 19 of the valve 17 with respect to the injection hole 13 in the nozzle body 8 (hole portion 12). By making the variable, the fuel can flow spirally inside the injection hole 13, and the shape of the spray from the injection hole 13 can be made appropriate.

The injection hole 13 includes an injection hole main portion 23, an injection hole inlet portion 24 upstream of the injection hole main portion 23, an injection hole outlet portion 25 downstream of the injection hole main portion 23, In the fuel injection nozzle 3, the cross-sectional area of the opening cross section of the injection hole inlet 24 is variable on the injection hole inlet 24 side. That is, at the intersection 26 between the injection hole 13 and the variable groove portion 19 (introduction fuel passage), the cross-sectional area of the injection hole inlet portion 24 can be made variable.

FIG. 6 is an explanatory diagram in which the cross section of the rotary valve 17 and the view from the axial direction of the corresponding injection hole 13 are arranged in parallel with the opening degree of the injection hole 13 in parallel. If the variable groove 19 and the injection hole inlet 24 of the injection hole 13 completely match each other, the opening degree of the injection hole inlet 24 (intersection 26) is 10 0% From this 100% opening degree, the □ -valve 17 is slightly rotated by the actuator 14 via the mouth-shaft 15 and the connecting part 16. In this case, the arc 13 of the rotary valve 17 slightly overlaps the injection hole inlet 24 of the injection hole 13, that is, the injection hole inlet 24 is slightly closed. The opening degree of the inlet 24 is 75%.

If the mouth valve 17 is further rotated and the sheet arc 18 closes half of the injection hole inlet 24, the opening of the injection hole inlet 24 becomes 50%. .

Further, if the valve 17 is rotated so that the sheet arc 18 closes most of the injection hole inlet 24, the opening of the injection hole inlet 24 can be reduced, for example. It can be 25%.

As shown in the case of each opening degree in FIG. 6, when viewed from the axial direction of the injection hole 13, a part of the periphery of the injection hole inlet portion 24 and the peripheral portion of the injection hole main portion 23 By overlapping a part of the nozzle hole, it is possible to enter the nozzle hole main part 23 from the most circumferential side of the nozzle hole 13, and the nozzle hole f, the mouth part 24 to the nozzle hole main part 23 The swirling flow of the fuel entering the air can be generated more effectively.

The timing of the rotation of the valve 17 by the actuator 14 is such that fuel is supplied to the dollar valve 9 in response to the intake or exhaust process of an engine (not shown). The timing can be such that the injection pressure is not applied.

Fig. 7 shows the initial stage of injection according to the opening of each injection hole 13 shown in Fig. 6. FIG. 4 is an explanatory view showing a visualized spray shape. At an opening degree of 100%, fuel from a fuel passage 22 is directly supplied from a variable groove 19 to an injection hole inlet portion 24 of an injection hole 13. It enters and is injected straight into the combustion chamber 27 of the engine from the injection hole outlet 25 without drawing a spiral inside the injection hole 13 (the injection hole main portion 23).

Therefore, the spray shape is linear as shown in the figure, and the penetration is the largest.

At an opening of 75%, the function of the swirl mechanism 11 slightly works.

That is, the fuel from the variable groove 19 (introduction fuel passage) to the injection hole inlet 24 of the injection hole 13 via the intersection 26 with the lift of the dollar valve 9 is Since it enters the injection hole main part 23 while wrapping around the sheet arc portion 18 of the valve 17, the direction of the wraparound direction (the injection hole) (13) is at a right angle from the direction of the variable groove 19), so that it enters at a predetermined pressure. Therefore, the direction of the resultant force of this wraparound force and the force in the direction of staying in the variable groove 19 Will be acted upon.

In addition, the inside of the injection hole main portion 23 of the injection hole 13 is a flow path limited to, for example, a circular cross section, and the fuel that has been acted on in the direction of the resultant force turns inside the injection hole main portion 23. As described above, that is, in a manner of drawing a spiral, the fuel reaches the injection hole outlet 25 and is injected into the combustion chamber 27.

Therefore, as shown in the figure, although the penetration is lower than when the opening degree is 100%, it is injected in the expanded state with a slight swirl, and each is injected. It can be seen that the swelling shape is slightly swelled, and that there are branches and leaves.

This tendency of spray spreading can be clearly seen at an opening of 50%.

In other words, the fuel that has entered the nozzle hole main part 23 with the nozzle hole inlet part 24 being half open is swirled off the axis of the nozzle hole main part 23 and swirled. Since the fuel is injected from the outlet 25, the spray shape is as shown in the figure.

Further, at an aperture of 25%, such a tendency is further promoted, and a swirling flow is induced in the injection hole 13 to obtain a swirling spray and a large spread shape. The injected fuel is well mixed with the air in the combustion chamber 27. Therefore, good and clean combustion can be realized.

Note that the shape of the spray is maintained symmetrical with respect to the injection hole 13 at each opening degree as shown in the figure.

FIG. 8 is a graph showing the relationship between the cam angle and the injection angle. It can be seen that the injection angle is larger when the opening degree is 50% than when the opening degree is 100%.

FIG. 9 is a graph showing the relationship between the cam angle and the penetration of the injection tip portion. The opening angle of 50% is larger than that of 100%. It can be seen that the net reduction has become smaller.

Next, FIG. 10 is a cross-sectional view taken along the line X-X of FIG. 4, and FIG. 11 is a view taken in the direction of the arrow XI of FIG. 4, wherein the injection hole 13 has its axis centered. Since the injection hole inlet 24 is opened at a predetermined opening degree (for example, 50%) by being biased to only one side, that is, the injection hole 13 is shielded only on one side, The fuel peels off only in the shielded direction, and the formed spray has the characteristic that it becomes non-axisymmetric with respect to the injection direction as shown in Fig. 10 or the injection direction changes during injection. . There is a problem that this property is not preferable for the engine.

FIG. 12 is an enlarged sectional view of a main part of a fuel injection nozzle 30 according to a second embodiment of the present invention for solving such a problem, and FIG. -XIII sectional view, Fig. 14 is a view in the direction of arrow IV in Fig. 12; in the swirl mechanism 31 of the fuel injection nozzle 30, the injection hole exit of the injection hole 13 A circular counterbore portion 32 was formed in the portion 25.

Also, for ease of comparison, the states of FIGS. 10 and 11 are shown in FIG. FIGS. 12 to 14 show the states shown in FIGS. 12 to 14.

FIG. 15 is a horizontal sectional view of the injection hole 13, a cross-sectional view of the injection hole 13, and a view in the axial direction of the injection hole 13 in the state of FIGS. 10 and 11. 16 is a horizontal sectional view of the injection hole 13 in the state shown in FIGS. 12 to 14 and a side cross section of the injection hole 13. FIG. 4 is an explanatory view showing the figure and a view taken in the direction of the axis of the injection hole 13 in parallel.

As shown in the figure (especially as shown in FIG. 16), in the fuel injection nozzle 30, the counterbore portion 32 is positioned with respect to the center line 23 C of the injection hole main portion 23. Injection hole 24 This is leaked to the sword center axis 24 C side.

That is, the injection hole inlet 24 of the injection hole 13 is shielded. For example, the injection hole outlet 25 of the injection hole 13 is enlarged on the right side in FIG. 14 while facing the left side in FIG. So that the flow path from the injection hole inlet 24 to the injection hole outlet 25 is not axisymmetric in the axial direction, that is, if the spray has the shape shown in FIG. In order to avoid this, an average spray shape can be formed.

The fuel injection nozzle 30 having such a configuration is deflected by the variable groove portion 19 of the rotary valve 17 to enter the injection hole 13 (the injection hole main portion 23) from the injection hole inlet portion 24 and turn. The fuel that has flowed will expand in the direction of the counterbore 32 only at the counterbore S2 of the injection hole outlet 25, and as shown in FIG. And a symmetrical spray shape.

That is, since the flow of the fuel can be uniformly separated and the spray can be evenly dispersed, an axisymmetric spray can be formed.

Of course, depending on the type of engine, the shape of the combustion chamber 27, and the like, conversely, when it is desired to further disperse the spray evenly, the same can be performed.

For example, contrary to the state shown in FIG. 16, the counterbore portion 32 is located on the side of the central axis line 24 C of the injection hole inlet portion 24 with respect to the central axis line 23 C of the injection hole main portion 23. If this is connected to the opposite side, the degree of non-axisymmetricity can be further increased. Therefore, depending on the direction of the offset of the counterbore part 32, it is possible to eliminate the bias of the spray (non-axisymmetric), to further increase the spread of the spray, or to set different directions such as horizontal and vertical. It is possible to bias the spray to a certain point.

FIGS. 17 to 20 show various examples of counterbore portions formed at the nozzle hole outlet 25 of the nozzle hole 13 in parallel with FIGS. 15 and 16. In the example shown in FIG. 17 which is an explanatory diagram shown in FIG. 17, the counterbore portion 33 is not a circular shape but an oblong shape, and the By forming 33, the effect of correcting the deflection direction by the ffi counterbore 33 can be made more effective.

In the example shown in FIG. 13, the counterbore portion 34 is formed in a circular shape larger than the nozzle hole outlet portion 25 of the nozzle hole 13 to promote the spraying action, and The mixing efficiency with air can be improved.

In the example shown in FIG. 19, the spot facing portion 35 has a triangular shape, and the spray shape can be a three-dimensional pyramid shape.

In the example shown in FIG. 20, the counterbore section 36 censored from the nozzle hole outlet section 25 has a conical shape, and the same as the counterbore section 32 in the example shown in FIG. 16. Further, by making the shape perpendicular to the forming direction of the injection hole inlet portion 24, the spray is made axially symmetric and can be further expanded.

As described above, in the first and second embodiments of the present invention, the swirl mechanism 11 can be configured by using the variable injection hole mechanism 10, but the general swirl mechanism without the variable injection hole mechanism 10 can be used. The swirl mechanism 11 can be configured with a simple nozzle configuration.

For example, Fig. 21 is a sectional view of the tip of a conventional general hole nozzle type fuel injection nozzle 40, and Fig. 22 is a sectional view taken along line XXI-XXI in Fig. 21. FIG. 23 is a view taken in the direction of the arrow XXIII of FIG. 21, and only the fuel passage 22 and the injection hole 13 are communicated with the lift of the needle valve 9. Hole 1 3 As shown in Fig. 22, the fuel injected from the fuel has a linear spray shape and does not have much spread.

FIG. 24 is a horizontal sectional view of the injection hole 13 of the fuel injection nozzle 50 according to the third embodiment of the present invention. FIG. 25 is a view of the same in the axial direction of the injection hole 13. In this fuel injection nozzle 50, the swirl mechanism 51 has an injection hole inlet 24 having a cross-sectional area smaller than the cross-sectional area of the injection hole main part 23, and the injection hole inlet 2 The opening cross section (center axis 24 C) of 4 is deviated from the opening cross section (center axis 23 C) of the injection hole main part 23.

Further, similarly to the case of each opening degree shown in FIG. 6, when viewed from the axial direction of the injection hole 13, a part of the circumference of the injection hole inlet portion 24 is formed around the injection hole main portion 23. By overlapping (inscribed) with a part of the nozzle hole, it is possible to enter the nozzle hole main part 23 from the most circumferential side of the nozzle hole 13, and from the nozzle hole inlet part 24 to the nozzle hole main part 2 The swirling flow of the fuel entering 3 is generated more effectively.

Of course, the degree of generation of the swirling flow in the injection hole 13 can be adjusted by arbitrarily selecting the formation position of the injection hole inlet portion 24.

For example, FIG. 26 is an axial view of an injection hole 13 of a fuel injection nozzle 52 according to a fourth embodiment of the present invention. In the swirl mechanism 53, an injection hole inlet portion is shown. The peripheral part of 24 does not coincide with the peripheral part of the nozzle hole main part 23, and the degree of generation of swirling flow is smaller than in the case of Fig. 25, but machining work can be performed more easily .

FIG. 27 is a horizontal sectional view of the injection hole 13 of the fuel injection nozzle 60 according to the fifth embodiment of the present invention, and FIG. 28 is a view in the direction of the axis of the injection hole 13. In this fuel injection nozzle 60, the swirl mechanism 61 has an injection hole inlet 24 having a cross-sectional area smaller than the cross-sectional area of the injection hole main part 23, and the injection hole inlet 2 The opening cross section (center axis 24 C) of 4 is deviated from the opening cross section (center axis 23 C) of the injection hole main part 23. However, the injection hole inlet portion 24 has a predetermined depth on the downstream side, and a part thereof faces the injection hole main portion 23.

Also in the fuel injection nozzle 60 and the swirl mechanism 6i having such a configuration, a swirl flow is generated in the injection hole 13 with a simple configuration, and swirl is applied to the spray to expand the injected fuel. The mixing ratio with air can be increased.

In addition, the rotational direction of the swirling flow can be selected depending on whether the injection hole inlet 24 is located at the right or left part toward the downstream side of the fuel injection direction. Is also adjustable.

In the present invention, the swirl mechanism can be provided not only at the injection hole inlet 24 but also at the injection hole outlet 25.

For example, FIG. 23 is an enlarged sectional view of a main part of a fuel injection nozzle 70 according to a sixth embodiment of the present invention, FIG. 30 is a sectional view taken along line XXX-XXX in FIG. FIG. 29 is a view taken in the direction of the arrow XXXI in FIG. 29. In the fuel injection nozzle 70, the swirl mechanism 71 is a circular seat eccentric to the injection hole outlet portion 25 of the injection hole 13. By forming the boring portion 72, a swirling flow can be generated in the injection hole 13.

Also in the fuel injection nozzle 70 and the swirl mechanism 71 of such a configuration, a swirl flow is generated in the injection hole 13 with a simple configuration, and swirling is applied to the spray to spread the injected fuel. By doing so, the mixing ratio with air can be increased.

Claims

The scope of the claims

(1) a nozzle hole having an injection hole inlet portion, an injection hole main portion and an injection hole outlet portion, and a nozzle hole forming a sheet surface;

A needle valve slidably provided in the nozzle body and liftable from the seat surface to enable fuel to be injected from the injection hole; and

A cross-sectional area of the injection hole entrance portion of the injection hole is made smaller than a cross-sectional area of the injection hole main portion,

The fuel injection nozzle according to claim 1, wherein an opening cross section of the injection hole inlet portion is displaced from an opening cross section of the injection hole main portion.

(2) a nozzle hole having an injection hole inlet portion, an injection hole main portion and an injection hole outlet portion, and a nozzle hole forming a sheet surface;

A fuel injection nozzle having a needle valve slidably provided in the nozzle body and capable of injecting fuel from the injection hole by lifting from the sheet surface; and

Reducing the cross-sectional area of the injection hole inlet portion of the injection hole smaller than the cross-sectional area of the injection hole main portion;

A fuel injection nozzle characterized in that the fuel flowing into the injection hole inlet can flow from a direction deviated from the axis of the injection hole main part.

3 A part of the periphery of the injection hole inlet portion and a part of the periphery of the injection hole main portion, viewed from the axial direction of the injection hole, are overlapped with each other. 2. The fuel injection nozzle according to 2. 4 An injection fuel passage intersecting with the injection hole is provided inside the injection hole, and an intersection between the injection fuel passage and the injection hole has a cross-sectional area smaller than a cross-sectional area of the injection hole main portion. The fuel injection nozzle according to any one of claims 1 to 3, wherein an injection hole inlet portion is formed.

5. The fuel injection nozzle according to claim 4, wherein the injection hole and the introduction fuel passage intersecting with the injection hole cross each other substantially at right angles.

6. The fuel injection nozzle according to claim 1, further comprising an injection hole variable mechanism that changes a cross-sectional area of the injection hole inlet portion.

7 The injection hole variable mechanism,

With actor

A rotary shaft attached to the actuator,

A rotary valve attached to the port shaft so as to be movable in the axial direction and to transmit the operating force in the rotational direction;

In this rotary knob,

a sheet arc portion that can close the injection hole

7. The fuel injection nozzle according to claim 6, wherein a fuel passage for introduction is formed between the sheet arc portions and communicates with the injection hole.

8. The fuel injection nozzle according to claim 1, wherein a counterbore deviated from the main portion of the injection hole is provided at an outlet portion of the injection hole.

9. The fuel injection nozzle according to claim 8, wherein the counterbore is biased toward a center axis of the injection hole inlet with respect to a center axis of the injection hole main portion.

A nozzle body having an injection hole inlet, an injection hole main portion, and an injection hole outlet, and a sheet surface;

A fuel injection nozzle having a needle valve slidably provided in the nozzle body and capable of injecting fuel from the injection hole by lifting from the seat surface; and A swirl mechanism is formed in the injection hole such that the fuel flowing from the injection hole inlet portion of the injection hole into the injection hole main portion flows while rotating spirally with respect to the axis of the injection hole. Characteristic fuel injection nozzle.

10. The fuel injection nozzle according to claim 10, wherein the swirl mechanism is provided at a visiting injection hole inlet portion.

12. The fuel injection nozzle according to claim 10, wherein the swirl mechanism is provided at the injection hole outlet.