JP2000320433A - Nozzle structure of fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable proper fuel injection at all times by providing a first injection hole whose fuel injection direction is variable and a second fuel injection hole, whose fuel injection is not variable in a nozzle structure of a fuel injection valve, and injecting fuel to a different direction according to the circumstance from the first injection hole. SOLUTION: A fuel injection valve is provided with a housing 60 and a valve element 61, and an injection hole 62 is formed in the end of the housing 60. the hole 62 has a main passage 63, extending in a predetermined direction and an auxiliary passage 64 extending in a direction different therefrom. When the valve element 61 is moved until only a fuel leading inlet 63a of the main passage 63 is opened, fuel is injected to the direction different from the direction A, when the valve element 61 is moved until the inlet 63a of the passage 63 and a fuel leading inlet 64a of the passage 64 are opened. An injection hole 82 formed at an end of the housing 60 extends in a predetermined direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a nozzle structure for a fuel injection valve.

[0002]

2. Description of the Related Art In order to atomize fuel injected from a fuel injection valve in a fuel chamber of an internal combustion engine, it has been conventionally performed to control a fuel injection mode in accordance with an operation state of the internal combustion engine. . For example, in JP-A-9-49470, the nozzle structure of a fuel injection valve has a first injection hole and a second injection hole that inject fuel at different angles with respect to a plane perpendicular to the axis of the fuel injection valve. Then, the injection mode of the fuel is controlled by selecting the injection hole for injecting the fuel according to the operation state of the internal combustion engine. Specifically, when the engine operation is in a low load state, fuel is injected only from the first injection hole, and when the engine operation is in a high load state, fuel is injected from the first injection hole and the second injection hole.

[0003]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 9-494.
In the fuel injection valve disclosed in Japanese Patent Publication No. 70, one of two fuel injection modes can be selected according to the engine operating state. However, it is preferable to be able to select from more fuel injection modes. It is an object of the present invention to provide more fuel injection modes.

[0004]

According to a first aspect of the present invention, there is provided a nozzle structure of a fuel injection valve for injecting fuel into a combustion chamber of an internal combustion engine, wherein a fuel injection direction is variable. It has a first injection hole and a second injection hole in which the fuel injection direction is unchanged. According to this, fuel is injected from the first injection hole in different directions depending on the situation, and fuel is always injected from the second injection hole in the same direction regardless of the situation.

According to a second aspect, in the first aspect, the first injection holes and the second injection holes are alternately arranged in the circumferential direction of the nozzle structure. According to a third aspect, in the first aspect, the angle of the fuel injection flow from the first injection hole with respect to a plane perpendicular to the axis of the fuel injection valve and the fuel from the second injection hole with respect to the same plane The angle of the jet can be made equal.

[0006]

FIG. 1 shows a case where the present invention is applied to a four-stroke compression ignition type internal combustion engine. Referring to FIG. 1, 1 is an engine body, 2 is a cylinder block, 3 is a cylinder head, 4 is a piston, 5 is a combustion chamber, 6 is an electrically controlled fuel injection valve, 7 is an intake valve, 8 is an intake port, 9 Denotes an exhaust valve, and 10 denotes an exhaust port. The intake port 8 is connected to a surge tank 12 via a corresponding intake branch pipe 11. Be linked. An inlet of the compressor 16 is connected to an air cleaner 18 via an air suction pipe 17, and a throttle valve 20 driven by a step motor 19 is arranged in the air suction pipe 17. The air suction pipe 17 upstream of the throttle valve 20
A mass flow detector 21 for detecting a mass flow rate of the intake air is disposed therein.

On the other hand, the exhaust port 10 is connected to the exhaust manifold 2.
The exhaust turbine 2 of the exhaust turbocharger 15 via the
3 and an outlet of the exhaust turbine 23 is connected via an exhaust pipe 24 to a catalytic converter 26 having a built-in catalyst 25 having an oxidizing function. Exhaust manifold 22
Inside, an air-fuel ratio sensor 27 is arranged. Exhaust pipe 28 connected to the outlet of catalytic converter 26 and throttle valve 2
The exhaust gas recirculation (hereinafter referred to as E)
(Referred to as GR) through a passage 29, and
E driven by a step motor 30 is provided in the passage 29.
A GR control valve 31 is provided. In the EGR passage 29, an intercooler 32 for cooling the EGR gas flowing in the EGR passage 29 is arranged. In the embodiment shown in FIG. 1, the engine cooling water is guided into the intercooler 32, and the engine cooling water cools the EGR gas.

On the other hand, the fuel injection valve 6 is connected via a fuel supply pipe 33 to a fuel reservoir, a so-called common rail 34. Fuel is supplied into the common rail 34 from an electric control type variable discharge fuel pump 35, and the fuel supplied into the common rail 34 is supplied to the fuel injection valve 6 through each fuel supply pipe 33. A fuel pressure sensor 36 for detecting the fuel pressure in the common rail 34 is attached to the common rail 34, and the fuel pump 35 is controlled so that the fuel pressure in the common rail 34 becomes the target fuel pressure based on the output signal of the fuel pressure sensor 36. Is controlled.

The electronic control unit 40 is composed of a digital computer, and is connected to a ROM (Read Only Memory) 42, a RAM (Random Access Memory) 43, a CPU (Microprocessor) 44, an input port 45, An output port 46 is provided. The output signal of the mass flow detector 21 is input to the input port 45 via the corresponding AD converter 47, and the output signals of the air-fuel ratio sensor 27 and the fuel pressure sensor 36 are also input to the input port via the corresponding AD converter 47, respectively. 45 is input. A load sensor 51 that generates an output voltage proportional to the amount of depression L of the accelerator pedal 50 is connected to the accelerator pedal 50, and the output voltage of the load sensor 51 is input to the input port 45 via the corresponding AD converter 47. . Also,
The input port 45 has a crank angle sensor 52 that generates an output pulse every time the crankshaft rotates, for example, by 30 °.
Is connected. On the other hand, the output port 46 is connected to the fuel injection valve 6, the throttle valve control step motor 19, the EGR control valve control step motor 3 via the corresponding drive circuit 48.
0 and the fuel pump 35.

Next, the nozzle structure of the fuel injection valve of the first embodiment will be described in detail. In this embodiment, the first injection holes 62 and the second injection holes 82 are alternately formed in the housing 60 at equal angular intervals around the axis of the fuel injection valve 6 as shown in FIG. The injection holes 62 and 82 extend in the radial direction of the housing 60, and the angle between the injection holes about the axis of the fuel injection valve, that is, the center axis C of the housing 60 is 30.
Degrees. FIG. 2 is a sectional view taken along line II-II in FIG.

As shown in FIG. 3, the fuel injection valve 6 of the first embodiment comprises a housing 60 and a valve body 61 slidably housed in the housing 60. Housing 6
0 is substantially cylindrical. The first injection holes 62 (only two are shown in FIG. 3) are provided at the substantially frustoconical tip of the housing 60. The first injection hole 62 has a main passage 63 extending in a predetermined direction and a sub passage 64 extending in a direction different from the main passage 63. The main passage 63 has a fuel introduction port 63a for introducing fuel into the main passage 63. On the other hand, the sub-passage 64 has a fuel inlet 64 a for allowing fuel to flow into the sub-passage 64. In this embodiment, the main passage 63 and the sub passage 64 have a common fuel injection port 65. That is, the main passage 63 and the sub passage 64 have a fuel inlet opening at a different position and a fuel injection opening opening at the same position. The valve body 61 is substantially cylindrical. The valve element 61 has a substantially cylindrical distal end 66 that fits into a substantially cylindrical space at the distal end of the housing 60. A space (hereinafter, referred to as a fuel storage space) 69 for storing fuel is formed between an outer wall surface 67 of the valve body 61 and an inner wall surface 68 of the housing 60. The distal end 66 of the valve element 61 includes a fuel flow passage 70 for communicating the fuel storage space 69 with the first injection hole 62. The valve body 61 is movable within the housing 60 along the central axis C of the housing 60.

As shown in FIG. 2, when the valve element 61 is moved until only the fuel introduction port 63a of the main passage 63 is opened, the fuel flows in the extending direction of the main passage 63, that is, as indicated by an arrow A in FIG. Injected in the direction. At this time, even if the fuel slightly leaks and flows into the sub-passage 64 through the space between the front end portion 66 of the valve body 61 and the inner wall surface at the front end of the housing 60, this fuel is deposited on the fuel flowing through the main passage 63. Common fuel injection port 6
Injected from 5. For this reason, the fuel leakage is caused by the fuel injection valve 6
Has a very small effect on the normal fuel injection flow from
Of course, the fuel injection flow is not formed separately from the normal fuel injection flow. Therefore, according to the present embodiment, the fuel is injected only in the correct direction.

When the valve body 61 is moved until the fuel inlet 63a of the main passage 63 and the fuel inlet 64a of the sub passage 64 are opened as shown in FIG. Injected in the direction. The direction of the arrow B is a direction between the extending direction of the main passage 63 and the extending direction of the sub passage 64, and the flow rate of the fuel flowing in the main passage 63 is smaller than the flow rate of the fuel flowing in the sub passage 64. Main passage 63
And the smaller the number, the closer to the extending direction of the sub flow path 64. Therefore, the variable range of the direction of the fuel flow injected from the fuel injection valve 6 is determined by adjusting the passage diameter and the extending direction of the main passage 63 and the sub passage 64.

In the first embodiment, the amount of fuel flowing into the fuel inlet of the auxiliary passage may be controlled by controlling the degree of movement of the valve body. In this case, the direction of the fuel injection flow from the first injection hole can be controlled more finely. The second injection holes 82 (only two are shown in FIG. 5) are provided at the substantially frustoconical tip of the housing 60. Further, the second injection holes 82 extend in a predetermined direction. Further, the second injection hole 82 is communicated with the fuel storage space 69 via the fuel flow passage 70.

As shown in FIG. 2, when the valve body 61 is moved until only the fuel inlet 63a of the main passage 63 is opened, fuel flows in the extending direction of the second injection hole 82, that is, in FIG.
Is injected in the direction of arrow D. Also, as shown in FIG. 4, when the valve body 61 is moved until the fuel introduction port 63a of the main passage 63 and the fuel introduction port 64a of the sub passage 64 are opened, the fuel also moves in the direction of arrow D in FIG. It is injected.
That is, fuel is always injected from the second injection hole 82 in a fixed direction regardless of the lift amount of the valve body 61. In this embodiment, a plane perpendicular to the center axis C of the housing (hereinafter, referred to as a plane).
The angle of arrow D with respect to the horizontal plane is equal to the angle of arrow B with respect to the horizontal plane.

Next, the operation of the fuel injection valve of this embodiment will be described in detail. In this embodiment, when the internal combustion engine is in a low load state, the valve body 61 is moved until only the fuel inlet 63a of the main passage 63 is opened. Accordingly, at this time, fuel is injected from the first injection hole 62 in the direction of arrow A, and fuel is injected from the second injection hole 82 in the direction of arrow D. That is, fuel is injected from the fuel injection valve at different angles with respect to the horizontal plane.

On the other hand, when the internal combustion engine is in a high load state, the valve body 61 is moved until the fuel inlet 63a of the main passage 63 and the fuel inlet 64a of the sub passage 64 are opened. Therefore, at this time, the fuel is injected from the first injection hole 62 in the direction of arrow B, and the fuel is injected from the second injection hole 82 in the direction of arrow D. That is, the fuel is injected from the fuel injection valve at an equal angle with respect to the horizontal plane.

As described above, according to the present invention, by combining the first injection hole capable of changing the fuel injection direction and the second injection hole whose fuel injection direction does not change, the fuel that can be selected according to the engine operating state. There are many choices for the fuel injection form from the injection valve. Further, as described above, the amount of fuel flowing into the fuel inlet of the sub-passage of the first injection hole can be controlled, and the direction of the fuel injection flow from the first injection hole can be controlled more finely, so that the fuel injection mode can be controlled. More choices.

As described above, in the present invention, the first injection holes and the second injection holes are alternately arranged in the circumferential direction of the fuel injection valve. Therefore, the angle of the fuel injection flow from the first injection hole with respect to the horizontal plane (hereinafter, the first fuel injection angle) and the angle of the fuel injection flow from the second injection hole with respect to the horizontal plane (hereinafter, the second fuel injection angle) ) Is different, the angles of the adjacent fuel injection flows in the circumferential direction of the fuel injection valve with respect to the horizontal plane are different. Therefore, interference between fuel injection flows caused by a lateral swirling flow (so-called swirl) formed in the combustion chamber is avoided. That is, if the angles of the adjacent fuel injection streams with respect to the horizontal plane are equal, these fuel injection streams may be mixed with each other under the influence of swirl, which is preferable from the viewpoint of promoting the atomization of fuel in the combustion chamber. Absent.
However, in the present invention, since the angles of the adjacent fuel injection flows with respect to the horizontal plane are different, atomization of the fuel in the combustion chamber is promoted.

Further, the present invention has an advantage that appropriate fuel injection can be performed even if more injection holes are provided in the fuel injection valve. That is, in general, when a larger number of injection holes are provided in the fuel injection valve, the distance between adjacent injection holes becomes narrower, so that the possibility of interference between fuel injection flows from each injection hole increases. However, as described above, in the present invention, interference between fuel injection flows is avoided, so that even if more injection holes are provided, fuel injection flows do not interfere with each other, and appropriate fuel injection is performed.

Further, in the present invention, the first fuel injection flow angle and the second fuel injection flow angle can be made equal according to the situation. This is advantageous when there is a demand to make the angle range of the fuel injection flow from the fuel injection valve with respect to the horizontal plane as narrow as possible. For example, in this embodiment, the first fuel injection angle and the second fuel injection angle are made equal when the engine operation is in a high load state. When the engine operation is in a high load state, the total amount of fuel injected from the fuel injection valve increases. In this case, atomization of fuel is promoted by equalizing each fuel injection flow angle and colliding with the wall surface of the fuel chamber. Therefore, there is an advantage in that each fuel injection flow angle can be equalized. Note that when the engine operation is in a low load state, the fuel is sufficiently atomized even in the combustion chamber, and therefore, in the present embodiment, the angles of the respective fuel injection flows are made different.

Further, in the present invention, fuel is injected from all the injection holes regardless of the state of operation of the engine. This is preferable from the viewpoint of promoting fuel atomization. That is, in order to promote the atomization of the fuel, it is convenient that the amount of fuel in the fuel injection flow from one injection hole is as small as possible. Accordingly, by injecting fuel from all the injection holes as in the present invention, the amount of fuel in the fuel injection flow from one injection hole can be reduced.

In this embodiment, when the engine operation is in a high load state, the first fuel injection angle is increased.
Also, according to the embodiment as shown in FIG. 7, when the engine operation is in a high load state, the first fuel injection flow angle may be reduced and may be equal to the second fuel injection flow angle. Whether the first fuel injection flow angle is reduced or increased when the engine operation is in a high load state may be appropriately selected in consideration of the fuel injection timing, piston shape, injection pressure, and the like.

[0024]

According to the first to third aspects of the present invention, the first injection hole which can change the fuel injection direction according to the situation, and the second injection hole which always injects the fuel in the same direction regardless of the situation. The combination with the injection hole increases the choice of the fuel injection form from the fuel injection valve.

[Brief description of the drawings]

FIG. 1 is a diagram showing an internal combustion engine employing a nozzle structure of a fuel injection valve according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the nozzle structure of the present invention.

FIG. 3 is a longitudinal sectional view of the nozzle structure of the present invention along a line III-III in FIG. 2;

FIG. 4 is a longitudinal sectional view of the nozzle structure of the present invention similar to FIG. 3 but in a different operating state.

FIG. 5 is a longitudinal sectional view of the nozzle structure of the present invention along line II-II in FIG. 2;

FIG. 6 is a view similar to FIG. 2 of a second embodiment of the present invention.

FIG. 7 is a view similar to FIG. 5 of a second embodiment of the present invention.

[Explanation of symbols]

 6 Fuel injection valve 62 First injection hole 82 Second injection hole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G066 AA07 AA11 AA13 AB02 AC01 AC09 AD12 BA00 BA02 BA03 CC18 CC23 CC28 CC30 CC48 DA00 DB08 DB09 DC04 DC05 DC11 DC18 DC24

Claims (3)

[Claims] In a nozzle structure of a fuel injection valve for injecting fuel into a combustion chamber of an internal combustion engine, a first injection hole having a variable fuel injection direction and a second injection hole having a constant fuel injection direction. The nozzle structure of a fuel injection valve having: 2. The nozzle according to claim 1, wherein the first injection holes and the second injection holes are alternately arranged in a circumferential direction of the nozzle structure.
3. The nozzle structure of a fuel injection valve according to 1. 3. An angle of a fuel injection flow from the first injection hole with respect to a plane perpendicular to an axis of the fuel injection valve is equal to an angle of a fuel injection flow from the second injection hole with respect to the same plane. The nozzle structure of a fuel injection valve according to claim 1, which can be used.