KR101588463B1 - Two Kind Fuel Injection Device Providing Multiple Injection for Dual Fuel Engine - Google Patents

Abstract

The present invention is improved to an integrated structure in which a mechanical injection drive structure and an electric fuel injection drive structure can be used in combination, and the fuel supplied through the different conduits is supplied to a micro-pilot injection, The main injection and the post injection are improved so as to be multi-stage, so that the performance of the engine can be increased with minimizing the installation space for the fuel injection device in the engine using the dual fuel.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a dual fuel injection system having a multi-stage injection function for a dual fuel engine,

The present invention relates to a dual fuel injection device having a multi-stage injection function for a dual fuel engine, and more particularly, to a dual fuel injection device having a multi-stage injection function for a dual fuel engine, The fuel supplied through the different pipelines is improved to have a multi-stage micro-pilot injection, main injection, and post-injection depending on the driving position of the needle shaft, thereby minimizing installation space for the fuel injection device So that the performance of the engine can be made higher.

Generally, in a diesel engine in which a dual fuel is used, a needle shaft is mechanically driven by a fuel injector and an electrically driven fuel injector. Accordingly, it takes a lot of space for mounting, which makes it difficult to secure a sufficient space for mounting. If necessary, rearrangement of peripheral components is also required to secure a space for mounting.

In the diesel engine employing the dual fuel injection device, the micro-pilot injection and the main injection are performed simultaneously in the cylinder in which the sucked air is compressed and the self-ignition method is applied. At this time, in the state where the micro pilot injection and the main injection are simultaneously performed, the mixing time of the compressed air and the fuel until the self-ignition is absolutely insufficient, so that the occurrence of smoke is excessive due to unstable combustion and fuel, There is a problem that the performance can not be increased and the nitrogen oxide (NOx) can not be reduced.

In order to solve the above problems, the present invention is improved to an integrated structure in which a mechanical injection drive structure and an electric fuel injection drive structure can be used in combination, and the fuel supplied through different conduits is supplied to a driving position of the needle shaft In this way, it is possible to reduce the installation space of the fuel injection device and increase the engine performance by improving the micro pilot injection and main injection to be multi-stage. And it is an object of the present invention to provide a fuel injection device.

In the present invention, a needle body is fixedly connected to a lower end of a valve body provided with first and second fuel injection ports and has first and second injection ports formed therein; A needle shaft accommodated in the valve body and the needle body; and a pressure adjusting shaft engaged with an inner surface of the valve body in a state of being disposed on the needle shaft; A solenoid shaft disposed between the needle shaft and the pressure regulating shaft; First and second conduits formed in the valve body to connect the first and second fuel injection ports to the first and second recessed portions; First and second fuel chambers formed at a lower portion of the needle body at an interval in the vertical direction; A fifth conduit formed in the needle shaft to communicate the first fuel chamber and the first groove; A sixth conduit formed in a downward direction from an upper surface of the needle shaft and connected to a second recessed portion of the needle shaft; And an elastic member having upper and lower ends elastically supported on the needle shaft and the valve body in a state where the valve body and the needle shaft are disposed between the valve body and the needle shaft.

There is also provided a dual fuel injection apparatus having a multi-stage injection function for a dual fuel engine in which a solenoid is mounted between the solenoid shaft and a valve body in a state of surrounding a solenoid shaft.

Also, a double fuel injection device having a multi-stage injection function for a dual fuel engine is provided, wherein a lower surface of the solenoid shaft is provided with a fourth groove portion communicating with a sixth duct opened to the upper surface of the needle shaft.

Also, a dual fuel injection device having a multi-stage injection function for a dual fuel engine is provided in which an inner surface of the needle body is provided with a keyway in its longitudinal direction and a key coupled with a keyway is formed on the needle shaft.

The valve body may have a stepped portion formed on an inner circumferential surface thereof so that the lower end of the elastic member is elastically supported, and the needle shaft may have a multi-end injection function for a dual fuel engine having an inner circumferential surface formed with a stepped portion, A double fuel injector is provided.

As described above, the present invention is improved to an integrated structure in which a mechanical injection drive structure and an electric fuel injection drive structure can be used in combination, and the fuel supplied through the different conduits is injected by micro- The main injection and the post injection are improved so as to be multi-stage, thereby suppressing the smoke generation and the generation of nitrogen oxides (NOx) in the diesel engine as well as minimizing the installation space for the fuel injection device in the engine using the dual fuel, The effect of increasing the performance can be expected.

1 is a cross-sectional view illustrating a dual fuel injection apparatus having a multi-stage injection function for a dual fuel engine according to the present invention.
2 is a sectional view showing the main part shown in Fig.
3 is a plan sectional view showing AA in Fig.
FIGS. 4A to 4C are cross-sectional views showing a mechanical drive in a dual fuel injection apparatus having a multi-stage injection function for a dual fuel engine according to the present invention, wherein FIG. 4A shows a micro pilot injection state, And FIG. 4C shows the post-injection state.
5A and 5B are cross-sectional views showing an electric drive in a dual fuel injection apparatus having a multi-stage injection function for a dual fuel engine according to the present invention, wherein FIG. 5A shows a state in which fuel is supplied, Respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing a dual fuel injection apparatus having a multi-stage injection function for a dual fuel engine according to the present invention, and FIG. 2 is a cross-sectional view showing the main part shown in FIG.

As shown in the drawings, the dual fuel injection apparatus 10 according to the present invention includes a valve body 12, a fixed cap 14 fixedly coupled to a lower end of the valve body 12, A needle body 16 fixedly connected to the lower surface of the valve body 12 in a coupling structure engaged with the valve body 12 and a needle shaft 18 slidably received through the valve body 12 and the needle body 16, A pressure regulating shaft 20 accommodated in the valve body 12 so as to be disposed on the upper portion of the needle shaft 18 and a solenoid shaft 20 disposed between the pressure regulating shaft 20 and the needle shaft 18. [ A solenoid 24 provided to surround the solenoid shaft 22 and first and second ejection openings 26 and 28 formed in the needle body 16. The first and second ejection openings 26 and 28 are formed in the needle body 16,

Specifically, the valve body 12 has a hollow structure. The valve body 12 is formed with first and second fuel injection ports 30 and 32 for individually injecting pressurized fuel.

The first and second conduits 34 and 36 are formed in the valve body 12 so as to communicate with the first and second fuel injection ports 30 and 32 in the downward direction. And the second conduits 34 and 36 communicate with the third and fourth conduits 38 and 40 corresponding to the needle body 16, respectively.

The third and fourth ducts 38 and 40 formed in the needle body 16 are in communication with the first and second yaw groove portions 42 and 44 respectively formed along the inner peripheral surface of the needle body 16 Lt; / RTI > At this time, the first recessed portion 42 is located at an upper portion from the second recessed portion 44.

A third yaw groove portion 46 corresponding to the first yaw groove portion 42 of the needle body 14 is formed in the lower portion of the needle shaft 18. The first yaw groove portion 42 and the third yaw groove portion 42 And the space 48 is formed when the first and second electrodes 46 and 46 face each other.

First and second fuel chambers 50 and 52 are formed at downwardly spaced positions from the third yaw groove 46 of the needle shaft 18 wherein the first and second fuel chambers 50 and 52 And the fifth channel 54 is connected to the inside of the needle shaft 18 so that the first fuel chamber 50 and the third yaw groove 46 of the needle shaft 18 communicate with each other. . A sixth conduit 56 connecting the upper surface of the needle shaft 18 to the second fuel chamber 52 of the needle shaft 18 is formed in the needle shaft 18.

An elastic member 58 is provided between the valve body 12 and the needle shaft 18 so as to surround the needle shaft 18. The stepped portion 60 is formed on the inner surface of the valve body 12 so that the lower end of the elastic member 58 is resiliently supported by the inner surface of the needle shaft 18 so that the upper end of the elastic member 58 can be elastically supported. An edgewise step 62 is formed. That is, the upper end of the elastic member 58 is resiliently supported by the needle shaft 18 and the lower end is resiliently supported by the valve body 12.

The solenoid shaft 22 is disposed in the valve body 12 and the lower surface of the solenoid shaft 22 is disposed on the upper surface of the needle shaft 18. A fourth yaw groove portion 64 is formed on the lower surface of the solenoid shaft 22 so as to communicate with the sixth conduit 56 that opens to the upper surface of the needle shaft 18. [ A solenoid 24 is mounted between the solenoid shaft 22 and the valve body 12 so as to surround the solenoid shaft 22.

The valve body 12 is provided with a pressure regulating shaft 20 on the upper portion of the solenoid shaft 22. The pressure regulating shaft 20 is coupled to the valve body 12 by a spiral have. A nut 66 for preventing the pressure regulating shaft 20 from being disengaged is fastened to the pressure regulating shaft 20 drawn out from the valve body 12.

When the pressure adjusting shaft 20 is to adjust the elastic force of the elastic member 58, first, the tightening of the nut 66 is released and the pressure adjusting shaft 20 is rotated in the tightening or releasing direction The solenoid shaft 22 and the needle shaft 18 are also engaged with each other in accordance with the direction of movement of the pressure adjusting shaft 20 so that the elastic member 58 is contracted or relaxed so that the elastic force is varied .

Fig. 3 is a plan sectional view showing A-A in Fig. As shown in the drawing, a key groove 68 is formed in the longitudinal direction on the inner surface of one side of the needle body 16, and a key 70 protrudes from the corresponding needle shaft 18. The key 70 is accommodated in the key groove 68 to prevent the needle shaft 18 from being rotated as the needle shaft 18 moves up and down. This prevents the fuel supplied to the first fuel chamber 50 and the second dye chamber 52 from being mixed with each other.

The low-grade fuel supplied to the second fuel chamber 52 is injected into the high-pressure fuel injector 26. The low-grade fuel injected into the second fuel chamber 52 is injected into the high- The key 70 and the key groove 68 are formed to prevent the needle shaft 18 from rotating in order to prevent the first ejection opening 26 from being blocked by the first ejection opening 26. [ (See Fig. 2)

Hereinafter, the operation of the dual fuel injection apparatus having the multi-stage injection function for the dual fuel engine according to the present invention will be described.

2, the first and second fuel chambers 50, 52 of the needle shaft 18 are connected to the first and second fuel chambers 50, 52, respectively, as shown in FIG. 2, The first and second fuel chambers 50 and 52 are blocked by the inner surface of the needle body 16 because the first and second injection ports 26 and 28 are located at a high position.

When the fuel is supplied through the first and second fuel injection ports 30 and 32 in the above state, the fuel supplied to the valve body 12 and the needle body 16, respectively, as shown in FIG. 4A, Are collected in the first and second recessed grooves (42, 44) along the first to fourth ducts (34, 36, 38, 40)

The fuel collected in the second recessed portion 44 is guided to the fourth recessed portion 64 of the solenoid shaft 22 along the sixth duct 56 of the needle shaft 18 through the second fuel chamber 52, .

The inner pressure of the fourth recessed trench 64 gradually increases due to the fuel collected in the fourth recessed trench 64 as described above and the pressure formed in the fourth recessed trench 64 is applied to the elastic member 58 ), The needle shaft 18 is lowered.

When the needle shaft 18 is lowered as described above, the first fuel chamber 50 is first brought into communication with the first injection port 26, so that the fuel existing in the first fuel chamber 50 The micro-pilot injection is performed through the first injection port 26. At this time, the second fuel chamber 52 is positioned higher than the second injection port 28, so that the main fuel injection through the second injection port 28 is not performed.

When the first fuel chamber 50 is further lowered beyond the first injection port 26 due to the continuous descent of the needle shaft 18, the fuel injection through the first injection port 26 is stopped.

4B, the second fuel chamber 52 is brought into communication with the second injection port 28. At this time, the second fuel chamber 52 is in communication with the second fuel injection port 28. In this case, And is positioned in a state where it extends over the groove portion 44 and the second jetting port 28. In other words, the upper partial space of the second fuel chamber 52 is in communication with the second yaw groove 44, and the lower partial space of the second fuel chamber 52 is communicated with the second jet opening 28 Communication state.
The fuel supplied to the second fuel injection port 32 is injected into the second injection port 28 through the second recessed portion 44 and the second fuel chamber 52 communicating with each other, 56 and the fourth recessed portion 64 are also discharged through the second fuel chamber 52 to the second injection port 28. [ At this time, the first injection port 26 is blocked by the needle shaft 18 as shown in the drawing, and the state in which the injection through the first injection port 26 is stopped is maintained.

When the fuel existing in the sixth conduit 56 and the fourth yaw groove 64 escapes from the main injection state as described above, the internal pressure of the fourth yaw groove 64 becomes low, The elastic member 58 which has been compressed due to the lowering of the needle shaft 18 is elastically collapsed in a state of overcoming the internal pressure of the fourth yaw groove 64 to lift the needle shaft 18. [
Accordingly, when the needle shaft 18 is raised, the second fuel chamber 52 is completely out of the second injection port 28, and the main fuel injection through the second injection port 28 is stopped.

When the first fuel chamber 50 is again brought into communication with the first injection port 26 as shown in FIG. 4C due to the continuous upward movement of the needle shaft 18, the first fuel chamber 50 Is in a state of being back-injected through the first ejection opening 28. [0050]

Then, due to the continuous upward movement of the needle shaft 18, the fuel injection supply is completed by being positioned in the state of FIG.

That is, in the present invention, micro-pilot injection, main injection, and post-injection are performed according to the rising and falling positions of the needle shaft 18 together with the new operating structure of the needle shaft 18, It is possible to increase the stable combustion and combustion performance, minimize the occurrence of smoke, and suppress the generation of nitrogen oxides (NOx). Thereby improving engine performance.

5A and 5B are cross-sectional views showing an electric drive in a dual fuel injection apparatus having a multi-stage injection function for a dual fuel engine according to the present invention. FIG. 5A shows a state in which fuel is supplied, The pilot injection state is shown.

2, the first and second fuel chambers 50 and 52 of the needle shaft 18 are connected to the first and second ejection openings 26 and 28, respectively, in the state where the needle shaft 18 is at the uppermost position, And the first and second fuel chambers 50 and 52 are blocked by the inner surface of the needle body 16.

When the fuel is supplied from the first fuel injection port 30 and the fuel is stopped through the second fuel injection port 32 in the above state, the driving of the needle shaft 18 is performed as shown in FIG. 5A . When the fuel supply through the second fuel injection port 32 occurs, the solenoid 24 operates.

The needle shaft 18 is forcibly lowered by the magnetic field generated by the operation of the solenoid 24 so that the first fuel chamber 50 communicates with the first jet port 26 as shown in FIG. The micro-pilot injection is performed.

When the operation of the solenoid 24 is stopped in the state where the fuel supply pressure is lowered by the above injection, the needle shaft 18 is raised by the elastic force of the elastic member 58 which has been compressed due to the fall of the needle shaft 18 And finally, the needle shaft 18 is placed in the states of FIGS. 5A and 2 to complete the fuel injection supply.

As described above, in the present invention, the micro-pilot injection, the main injection, and the post-injection are performed in multiple stages according to the movement position of the needle shaft 18, but the present invention is not limited thereto. For example, when the positions of the first and second fuel chambers 50 and 52 are changed so that the needle shaft 18 is positioned at the lowermost position, the micro-pilot injection and the main injection are simultaneously performed, and the needle shaft 18 And the fuel supply is terminated by moving to the uppermost stage.

10: Double fuel injector 12: Valve body
14: fixed cap 16: needle body
18: Needle shaft 20: Pressure regulating shaft
22: Solenoid 26: 1st nozzle
28: second jet opening 30: first fuel inlet
32: second fuel inlet 34: first channel
36: second conduit 38: third conduit
40: fourth pipe 42: first pour groove
44: second recessed groove 46: third recessed groove
48: space 50: first fuel chamber
52: second fuel chamber 54: fifth channel
56: Sixth conduit 58: Elastic member
60, 62: step portion 64: fourth groove portion
66: nut 68: keyway
70: Key

Claims (5)

A needle body 16 fixedly connected to a lower end of a valve body 12 having first and second fuel injection ports 30 and 32 and formed with first and second injection ports 26 and 28;
A needle shaft 18 which is accommodated in the valve body 12 and the needle body 16 and a pressure regulating shaft 20 which is fastened to the inner surface of the valve body 12 in a state of being disposed on the needle shaft 18 );
A solenoid shaft (22) disposed between the needle shaft (18) and the pressure regulating shaft (20);
First and second conduits (34, 36) formed in the valve body (12) to connect the first and second fuel injection ports (30, 32) and the first and second recessed portions (42, 44);
First and second fuel chambers (50, 52) formed at a lower portion of the needle body (16) at an interval in the vertical direction;
A fifth conduit (54) formed in the needle shaft (18) to communicate the first fuel chamber (50) and the first yaw groove (46);
A sixth conduit 56 formed downward from the upper surface of the needle shaft 18 and connected to the second yaw groove 44 of the needle shaft 18;
And an elastic member 58 whose upper and lower ends are elastically supported by the needle shaft 18 and the valve body 12 in a state of being disposed between the valve body 12 and the needle shaft 18. [ A double fuel injector having a multi - stage injection function for a fuel engine.
The method according to claim 1,
Wherein a solenoid (24) is mounted between the solenoid shaft (22) and the valve body (12) so as to surround the solenoid shaft (22).
3. The method of claim 2,
Wherein a lower end of the solenoid shaft (22) is provided with a fourth yaw groove (64) for communicating with a sixth conduit (56) opened to the upper surface of the needle shaft (18) The fuel injection system comprising:
The method of claim 3,
Wherein a key groove (68) is formed in an inner surface of the needle body (16) in a longitudinal direction and a key (70) coupled to the needle shaft (18) by a key groove (68) A double fuel injection device having a multi-stage injection function for an engine.
5. The method according to any one of claims 1 to 4,
A stepped portion 60 is formed on the inner circumferential surface of the valve body 12 so as to elastically support the lower end of the elastic member 58. The needle shaft 18 is provided with an elastic member 58, And a step portion (62) is formed on the outer circumferential surface of the double fuel injector.

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