JPH04330326A - Fuel injection nozzle - Google Patents

Abstract

PURPOSE:To promote pulvarization of fuel injected from small injection ports so as to develop ignition and combustion in the upper portion of an auxiliary chamber by providing the small Injection ports and a large injection ports. CONSTITUTION:In a fuel injection nozzle, a needle valve opens injection ports formed in a nozzle main body with application of a fuel pressure to the needle valve, thus injecting fuel. The injection ports are provided with a plurality of small injection ports 4 for injecting fuel in the almost horizontal direction and a plurality of large injection ports 5 for injecting fuel downward of the fuel injection from the small injection ports 4. Fuel pulverization of fuel atomization injected from the small injection ports 4 is promoted, followed by ignition and combustion in the upper portion of an auxiliary chamber 2. A non-combustion mixture of the atomized fuel injected toward the lower portion of the auxiliary chamber 2 from the large injection ports 5 is blown out of a connection hole 3, thereby improving an engine output and thermal efficiency.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a fuel injection nozzle for injecting fuel into a combustion chamber such as an auxiliary chamber formed in a cylinder head.

0002

[Prior Art] Generally, when forming a nozzle hole at the tip of the nozzle body of a fuel injection nozzle, the nozzle hole is directly machined into the nozzle body by drilling, electrical discharge machining, etc., and the shape of the nozzle hole is also It is limited to shapes that can be drilled using the following processing method. By the way, regarding the nozzle holes formed at the tip of the nozzle in a fuel injection nozzle, the nozzle hole diameter and the number of nozzle holes are conditions that greatly affect the combustion state, and the determination of these conditions for the nozzle holes depends on the engine. It is also related to performance and is an important element in improving engine performance. Furthermore, it has been known from the past that not only the nozzle hole diameter and the number of nozzle holes, but also the nozzle hole configuration such as the nozzle hole shape and nozzle hole angle have a large effect on combustion. For example, by changing the shape of the nozzle hole of the fuel injection nozzle from a conventional circular shape to an irregular shape such as a square shape, the velocity distribution of spray particles can be changed and air intake can be improved.

[0003] Regarding the above-mentioned nozzle hole, there is one disclosed in Japanese Patent Application No. 1-252277 filed by the present applicant. The fuel injection nozzle disclosed in the publication is
As shown in FIG. 10, a ceramic nozzle body 51 is provided with a nozzle 53 at its tip that opens into the combustion chamber for fuel injection.
, and a ceramic needle valve 52 arranged to be movable up and down within the nozzle body 51. The fuel injection nozzle is
When fuel pressure is applied to the needle valve 52, the needle valve 52 moves relative to the nozzle body 51, the needle valve 52 opens the nozzle 53, and the fuel from the fuel passage 55 is injected from the nozzle 53. ing. The nozzle port 53 is composed of a large number of nozzle holes, and is formed in multiple stages in the axial direction at the tip of the nozzle body 51.

[0004] Furthermore, as a pre-chamber type adiabatic engine, the one shown in FIG. 7 has been disclosed. The pre-chamber type adiabatic engine includes a cylinder block 40 forming a cylinder 49;
a cylinder head 42 fixed to a cylinder block 40;
A sub-chamber 44 having a heat insulating structure formed in the cylinder head 42;
A piston 48 that reciprocates within a cylinder 49 and a secondary chamber 44
The fuel injection nozzle 41 has a communication hole 46 that communicates with the main chamber 43 and a fuel injection nozzle 41 that opens an injection port 47 into the sub chamber 44 . The subchamber 44 can be formed in various shapes, for example, as shown in FIG. 8, it can be formed in a side wall surface 45 with a circular cross section, or as shown in FIG. The side wall surface 50 can be formed in a rectangular shape. The fuel injected from the nozzle 47 collides with the side wall surface 45 or 50, ignites and burns, and is blown out from the auxiliary chamber 44 through the communication hole 46 into the main chamber 43.

[0005]

[Problems to be Solved by the Invention] However, in the fuel injection nozzle as shown in FIG.
7, the fuel injected from the multiple injection holes 47 collides with the sub-chamber wall surface 45 (see FIG. 8) or 50 (see FIG. 9) and is diffused, thereby causing the fuel and air in the sub-chamber 44 to mix. Although mixing has been achieved, the fuel injected from the multiple injection holes 47 flows into the subchamber 44.
In particular, the fuel spray cannot be diffused well over the entire area within the pre-chamber 44, and the fuel and air cannot be mixed well, resulting in ignition combustion within the pre-chamber 44. This is not carried out well, and the air blowing out from the communication hole 46 is weak, resulting in a decrease in engine output, a decrease in thermal efficiency, and the generation of HC, NOX, etc.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems, and to improve the combustion of a pre-chamber type engine, by providing a multi-injection port that injects water in a substantially horizontal direction toward the upper wall surface of the pre-chamber. A small nozzle is formed into a small nozzle, and a large nozzle is formed with multiple nozzles that inject diagonally downward on the lower wall surface of the auxiliary chamber, and the fuel atomization of the fuel spray injected from the small nozzle is promoted to first reach the upper part of the auxiliary chamber. To provide a fuel injection nozzle that improves engine output and thermal efficiency by igniting and burning the fuel and blowing out the unburned mixture of fuel spray injected from the large nozzle toward the lower part of the auxiliary chamber from the communication hole.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention is constructed as follows. That is,
The present invention has a nozzle body in which a fuel passage is formed and a needle valve arranged to be able to reciprocate within a hollow hole formed in the nozzle body, and by applying fuel pressure to the needle valve, the needle valve In a fuel injection nozzle that injects fuel by opening multiple injection ports formed in a nozzle body, the multiple injection ports include a plurality of small injection ports extending in a substantially horizontal direction of the nozzle body so as to inject fuel in a substantially horizontal direction of the nozzle main body. The present invention relates to a fuel injection nozzle having a nozzle and a plurality of large nozzles that extend downward in the axial direction of the nozzle body so as to inject fuel downward from the small nozzle.

Further, in this fuel injection nozzle, the multi-nozzle opening is opened in a sub-chamber having a heat-insulating structure and the side wall surface of the cylinder head is formed into a rectangular cross section, and the fuel injected from the small nozzle of the multi-nozzle nozzle is sub-chambered. The fuel injected from the large nozzle of the multiple nozzles is reflected by collision against the side wall surface of the lower part of the sub-chamber.

Alternatively, the present invention provides a valve including a nozzle body having a hole extending in the axial direction, a fuel passage fitted to be able to reciprocate within the hole, and a fuel passage from the fuel passage of the valve to the fuel passage. A fuel having multiple nozzle holes formed in the valve penetrating the outer periphery, and applying fuel pressure to the valve to move the valve relative to the nozzle body and opening the multiple nozzle holes to inject fuel. In the injection nozzle,
The multiple injection ports include a plurality of small injection ports that extend substantially horizontally of the valve so as to inject fuel in a substantially horizontal direction, and a plurality of small injection ports that are inclined downward in the axial direction of the valve so as to inject fuel downward from the small injection ports. The present invention relates to a fuel injection nozzle characterized by having a plurality of extending large nozzles.

0010

[Operation] The fuel injection nozzle according to the present invention is constructed as described above and operates as follows. That is, this fuel injection nozzle is arranged so that multiple nozzles are opened in the subchamber of a subchamber type engine, and the small nozzle is formed with multiple nozzles that inject water almost horizontally toward the upper wall surface of the subchamber. Since the large nozzle is formed with multiple nozzles that inject diagonally downward on the lower wall of the chamber, atomization of the fuel spray injected from the small nozzle is promoted, and the entrainment property of the jet flow, that is, the entrainment of air, is reduced. This promotes the mixing of fuel and air, which ignites and burns in the upper part of the pre-chamber. On the other hand, in the lower part of the auxiliary chamber, fuel is injected from a large nozzle, and a large amount of injected fuel does not ignite, and the fuel and air are in an unburnt mixture state where they are mixed to some extent. Therefore, when combustion starts in the upper part of the pre-chamber, its volume expands rapidly,
The unburned air-fuel mixture in the lower part of the auxiliary chamber is vigorously blown out from the auxiliary chamber through the communication hole into the main chamber, mixes with fresh air present in the main chamber, and generates a strong force or output that pushes the piston.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a fuel injection nozzle according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view of essential parts showing one embodiment of a fuel injection nozzle according to the present invention, FIG. 2 is a schematic explanatory view showing a spray pattern of fuel injection when the fuel injection nozzle of FIG. 1 is arranged in a subchamber, and Figure 3 is Figure 2
FIG. 2 is a schematic explanatory diagram showing a spray pattern of fuel injection as seen from line A-A of FIG.

Although not shown, the fuel injection nozzle according to the present invention has a nozzle body 6 in which a fuel passage is formed and a needle valve reciprocably disposed in a hollow hole formed in the nozzle body 6. By applying fuel pressure to the valve, the needle valve opens multiple injection ports formed in the nozzle body 6 and injects fuel. Regarding this fuel injection nozzle, as shown in FIG. 1, the multi-nozzle has a plurality of small nozzles 4 that inject fuel in a substantially horizontal direction and a plurality of large nozzles 5 that inject fuel downward from the small nozzles 4. have. In Figure 1, the small nozzle 4
is a fuel sac portion 10 formed at the tip of the nozzle body 6.
A plurality of large nozzles 5 are formed spaced apart in the circumferential direction at the upper part of the fuel sack part 10, and a plurality of large nozzle holes 5 are formed at a lower part of the fuel sack part 10 so as to extend downwardly and are spaced apart in the circumferential direction below the small nozzle holes 4. ing.

This fuel injection nozzle is preferably disposed in the subchamber 2 of the subchamber type engine, as shown in FIG. In other words, the pre-chamber type engine includes a cylinder head 7 fixed to the cylinder block, a pre-chamber 2 with a heat insulating structure formed in the cylinder head 7, a piston that reciprocates within the cylinder formed in the cylinder block, and a nozzle in the sub-chamber 2. It has a fuel injection nozzle 6 with an open side and a main chamber 1 formed on the piston side. When the sub-chamber 2 is configured to have a heat-insulating structure, it can be constructed, for example, from a sub-chamber wall made of ceramics or the like having high heat resistance and heat insulation properties and placed in a hole formed in the cylinder head 7. . The auxiliary chamber 2 communicates with the main chamber 1 through a communication hole 3. Further, the main chamber 1 may be formed in the cavity of the piston head or in a space surrounded by the upper part of the liner and the lower surface of the head, and may be constructed of a heat-insulating structure using ceramics or the like.

In this pre-chamber type engine, the pre-chamber 2 has a shape such that the pre-chamber wall surface 8 has a rectangular cross section, as shown in FIG. The fuel injection nozzle 6 arranged in the sub-chamber 2 sprays fuel radially into the sub-chamber 2 and includes multiple injection ports formed in the circumferential direction of the nozzle axis so that the injected fuel can collide with the sub-chamber wall surface 8. There is. The fuel injection nozzle 6 is arranged in the auxiliary chamber 2 at a substantially central portion extending downward in the axial direction, and the multiple injection ports are open toward the wall surface 8 of the auxiliary chamber 2 . in this way,
When the fuel injection nozzle 6 is placed in the auxiliary chamber 2, the fuel injected from the small nozzle 4 of the multiple nozzles forms a small spray pattern B.
The light collides with the wall surface 8 of the rectangular side of the upper part of the subchamber, is reflected, and diffuses into the subchamber 2. Further, the fuel injected from the large nozzle 5 with multiple nozzles forms a large spray pattern C, collides with the wall surface 8 of the square corner 9 at the lower part of the sub-chamber, is reflected, and diffuses into the sub-chamber 2 in a conical shape. .

Furthermore, in this fuel injection nozzle, the amount of fuel injected from the small nozzle 4 is smaller than that from the large nozzle 5. Furthermore, the distance that the injected fuel from the small nozzle 4 reaches the wall surface 8 is the same as the distance that the injected fuel from the large nozzle 5 reaches the wall surface 8.
is shorter than the distance reached. Therefore, first, the injected fuel from the small nozzle 4 collides with the wall surface 8, is reflected and diffused, and mixes with air, and ignition combustion begins within the subchamber 2. Next, a large amount of injected fuel from the large nozzle 5 collides with the wall surface 8, is reflected and diffused, and mixes with air to some extent, and the large amount of injected fuel does not ignite, and the fuel and air mix to some extent. The mixture becomes unburned. Therefore, even if the temperature inside the subchamber 2 becomes extremely high and the ignition delay becomes short, ignition will occur reliably in the upper part of the subchamber and there will be no misfire. Therefore,
When the fuel injected from the small nozzle 4 begins to burn in the upper part of the pre-chamber,
In order to rapidly expand its volume, the unburned air-fuel mixture in the lower part of the pre-chamber turns into combustion gas and flame, which are vigorously blown out from the pre-chamber 2 through the communication hole 3 into the main chamber 1 at high speed, and are present in the main chamber 1. It mixes with fresh air in a short time, shortens the combustion period, and burns completely in good conditions. Moreover, it reduces the generation of HC and N.
Combustion can be performed while suppressing the generation of OX, and a strong force or output to push the piston is generated.

Next, another embodiment of the fuel injection nozzle according to the present invention will be described with reference to FIGS. 4, 5 and 6. This fuel injection nozzle can be applied to the poppet covered orifice type with zero sack volume, which is disclosed in Utility Application No. 3-8465 filed by the present applicant, and an example of this will be explained below. do. Therefore, it goes without saying that it can also be applied to types other than those described below. This fuel injection nozzle includes a holder 24 that is provided with a fuel passage 23 in the longitudinal direction at the center of the axis for introducing fuel supplied from a fuel injection pump, and a nozzle body 12 that is fixed to the lower end of the holder 24 with screws or the like. , a valve 13 fitted in a hole 11 formed in the longitudinal direction of the central part of the axis formed in the nozzle body 12 so as to be movable up and down, that is, slidable; a retainer 25 fixed to the upper end of the valve 13; A return spring 28 disposed between the retainer 25 and washers 26 and 27 disposed on the upper end surface of the nozzle body 12
has. A seal 29 is interposed between the holder 24 and the nozzle body 12. Further, in order to limit the range of vertical movement of the valve 13 relative to the nozzle body 12, that is, the lift amount, a lift stopper 30 is disposed between the upper end surface of the nozzle body 12 and the lower end surface of the retainer 25.

In this fuel injection nozzle, a valve seat 32 is formed on the end surface 15 of the nozzle body 12. A valve ring 14 is fitted into a protrusion 18 formed at the tip of the valve 13. This valve ring 14
A valve face 31 is formed on the upper surface of the nozzle body 12, and the valve face 31 is configured to come into contact with a valve seat 32 of the nozzle body 12. When the valve seat 32 and the valve face 31 come into contact, a liquid-tight seal is provided between the nozzle body 12 and the valve 13. The valve 13 is the nozzle body 1
A key 33 is inserted so as to straddle both sides so that it can slide in the vertical direction with respect to the key 2 but cannot rotate in the rotational direction.

This fuel injection nozzle includes a nozzle body 12 having a hole 11 formed therein, a nozzle body 12 that is slidably fitted within the hole 11 of the nozzle body 12, and a fuel passage 16 in the center that communicates with the fuel passage 16. The valve 13 has a plurality of multi-nozzle ports 20 and 21 formed therein. The valve 13 is slidably moved in the vertical direction with respect to the nozzle body 12 by a predetermined lift amount. In this fuel injection nozzle, a fuel passage 16 is formed in the longitudinal direction of the axial center of the valve 13 . Further, the valve 13 is formed with a plurality of fitting holes 19 which have one end open to the fuel passage 16 and the other end open to the outer peripheral surface side. The nozzle forming body 17 is fitted into the fitting hole 19 . Therefore, when each nozzle forming body 17 is fitted into the fitting hole 19 of the valve 13, the plurality of multiple nozzles 20 and 21 formed on the nozzle forming body 17 are formed on the valve 13.

Regarding this fuel injection nozzle, valve 1
When fuel pressure is applied to the nozzle body 1, the valve 13 closes to the nozzle body 1.
2, the multiple injection ports 20 and 21 are opened, and fuel is injected. That is, as shown in FIG. 6, if the valve 13 is slid downward relative to the nozzle body 12 by the lift amount L, the valve seat 32 of the nozzle body 12 and the valve ring 14 fitted to the valve 13
An annular gap 22 is formed between the valve face 31 and the plurality of nozzles 20 and 21 formed in the nozzle forming body 17 are opened into the annular gap 22.

In particular, in this fuel injection nozzle, the multiple nozzles formed in the nozzle forming body 17 are composed of a plurality of small nozzles 20 formed at the lower part of the nozzle forming body 17 and a plurality of large nozzles 21 formed at the upper part. There is. The small nozzle 20 has a large cone opening angle so as to inject fuel in a substantially horizontal direction. Further, the cone opening angle of the large nozzle 21 is formed to be small so that fuel is injected downward from the small nozzle 20 . That is, a plurality of small nozzles 20 are formed at intervals in a substantially horizontal direction, that is, a circumferential direction, of the valve 13 so as to inject fuel in a substantially horizontal direction, and the large nozzle 21 injects fuel downward from the small nozzle 20. A plurality of them are formed so as to be inclined downward in the axial direction of the valve 13 and spaced apart from each other so as to inject. Therefore, the multiple injection ports 20 of this fuel injection nozzle,
21 is arranged so as to open into the auxiliary chamber of a heat-insulating structure, the fuel injected from the small nozzle hole 20 can be reflected by collision with the side wall surface of the upper part of the auxiliary chamber, and the fuel injected from the large nozzle hole 21 can be reflected. can be reflected by collision with the corner side wall surface of the lower part of the subchamber. Since the function of this fuel injection nozzle is similar to that of the fuel injection nozzle shown in FIG. 1, the explanation thereof will be omitted here.

[0021]

The fuel injection nozzle according to the present invention is constructed as described above and has the following effects. That is, this fuel injection nozzle has a nozzle body in which a fuel passage is formed and a needle valve that is reciprocally arranged in a hollow hole formed in the nozzle body, and by applying fuel pressure to the needle valve, It can be applied to a type of fuel injection nozzle in which a needle valve injects fuel by opening multiple injection ports formed in the nozzle body,
Since the multiple nozzle has a plurality of small nozzles that inject fuel in a substantially horizontal direction and a plurality of large nozzles that inject fuel downward from the small nozzles, the fuel atomization of the fuel spray injected from the small nozzles is reduced. This promotes the entrainment property of the jet, that is, the entrainment of air, and promotes the mixing of fuel and air. On the other hand, the amount of fuel injected from the large nozzle is large, ignition does not occur, and the fuel and air are in an unburnt mixture state where they are mixed to some extent.

Therefore, if this fuel injection nozzle is placed in a sub-chamber of a heat-insulating structure in which the side wall surface of the cylinder head is formed into a rectangular cross-section, and a small nozzle and a large nozzle are opened in the sub-chamber, the air from the small nozzle is The injected fuel can be reflected by colliding with the side wall surface of the upper part of the subchamber, and the fuel injected from the large nozzle can be collided with and reflected by the side wall surface of the corner part of the lower part of the subchamber. Since the fuel spray injected from the small nozzle has a horizontal and circular spray pattern B toward the side wall surface of the upper part of the sub-chamber, the distance to the wall is short, and the fuel spray from the small nozzle First, the fuel collides with the wall surface, promoting atomization of the fuel, and ignition combustion begins in the upper part of the pre-chamber, causing its volume to rapidly expand. On the other hand, in the case of injection from the large nozzle, a large amount of fuel is injected, and it is injected toward the corner side wall surface at the bottom of the subchamber, so the distance to the wall surface is far, and the fuel and air are mixed to some extent. In this state, ignition does not occur and the unburned mixture remains, and the unburnt mixture is vigorously blown out from the subchamber through the communication hole into the main chamber. The combustion gas and mixture blown into the main chamber mix with the fresh air present in the main chamber for a short period of time, shortening the combustion period and increasing the combustion speed, generating a strong force that pushes the piston, that is, engine output. .

Alternatively, this fuel injection nozzle includes a nozzle body having a hole extending in the axial direction, a valve having a fuel passage fitted so as to be able to reciprocate within the hole, and the fuel passage of the valve. The valve has a multi-nozzle hole formed in the valve that penetrates through the outer periphery of the nozzle, and the valve is moved relative to the nozzle body by applying fuel pressure to the valve. The present invention can also be applied to a type of fuel injection nozzle that injects fuel by opening the small nozzle port and the large nozzle port, and the same effects as those of the above-mentioned types can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of essential parts showing an embodiment of a fuel injection nozzle according to the present invention.

FIG. 2 is a schematic explanatory diagram showing a spray pattern of fuel injection when the fuel injection nozzle of FIG. 1 is arranged in an auxiliary chamber.

FIG. 3 is a schematic explanatory diagram showing a spray pattern of fuel injection as seen from line AA in FIG. 2;

FIG. 4 is a sectional view showing another embodiment of the fuel injection nozzle according to the present invention.

FIG. 5 is a sectional view of a main part of the fuel injection nozzle in FIG. 4, showing a non-spraying state.

6 is a sectional view of a main part showing a spray pattern of the fuel injection nozzle of FIG. 4 during spraying; FIG.

FIG. 7 is a schematic explanatory diagram showing an example of a case where a conventional fuel injection nozzle is arranged in a pre-chamber type engine.

FIG. 8 is an explanatory diagram showing an example of an auxiliary chamber in which the fuel injection nozzle of FIG. 7 is arranged.

FIG. 9 is an explanatory diagram showing another example of the subchamber in which the fuel injection nozzle of FIG. 7 is arranged.

FIG. 10 is an explanatory diagram showing an example of a conventional fuel injection nozzle.

[Explanation of symbols]

1 Main room 2 Antechamber 3 Communication hole 4 Small spout 5 Large spout 6 Nozzle body 7 Cylinder head 8 Wall surface 9 Corner 11 Hole 12 Nozzle body 13 Valve 14 Valve ring 15 Bottom surface 16 Fuel passage 17 Fountain forming body 20 Small spout 21 Large spout

Claims (3)

[Claims] 1. A nozzle body having a fuel passage formed therein, and a needle valve disposed so as to be able to reciprocate within a hollow hole formed in the nozzle body, wherein the needle valve is activated by applying fuel pressure to the needle valve. In a fuel injection nozzle that injects fuel by opening multiple injection ports formed in the nozzle body, the multiple injection ports include a plurality of injection ports extending in a substantially horizontal direction of the nozzle body so as to inject fuel in a substantially horizontal direction of the nozzle main body. A fuel injection nozzle comprising a small nozzle and a plurality of large nozzles that extend downward in the axial direction of the nozzle body so as to inject fuel downward from the small nozzle. 2. The multiple injection ports are opened in a pre-chamber having a heat insulating structure and the side wall surface of the cylinder head is formed into a rectangular cross section, and the fuel injected from the small injection ports of the multiple injection ports is directed to the side of the upper part of the sub-chamber. 2. The fuel injection nozzle according to claim 1, wherein the fuel injection nozzle collides with and reflects on a wall surface, and the fuel injected from the large nozzle of the multiple nozzles collides with and reflects on a corner side wall surface of a lower part of the auxiliary chamber. 3. A nozzle body having a hole extending in the axial direction, a valve having a fuel passage fitted to be reciprocally movable within the hole, and penetrating from the fuel passage of the valve to the outer periphery. A fuel injection nozzle having multiple injection ports formed in the valve, and moving the valve relative to the nozzle body by applying fuel pressure to the valve and opening the multiple injection ports to inject fuel, The multiple injection ports include a plurality of small injection ports that extend substantially horizontally of the valve so as to inject fuel in a substantially horizontal direction, and a plurality of small injection ports that are inclined downward in the axial direction of the valve so as to inject fuel downward from the small injection ports. A fuel injection nozzle characterized by having a plurality of extending large nozzles.