KR20120027899A - Two kind fuel injection device providing multiple injection for dual fuel engine - Google Patents

Abstract

PURPOSE: A double fuel injection system having a multi-stage injection function for a double fuel engine is provided to improve combustion performance by reducing smoke and controlling the generation of nitrogen oxide. CONSTITUTION: A double fuel injection system having a multi-stage injection function for a double fuel engine comprises a needle body(16), a needle shaft(18), a pressure adjusting shaft(20), a solenoid shaft(22), first and second pipelines(34,36), first and second fuel chambers(50,52), fifth and sixth pipelines, and an elastic member(58). The needle body is connected to the bottom end of a valve body(12). The needle shaft is accepted in the valve body and the needle body. The pressure adjusting shaft is coupled to the inner surface of the valve body. The solenoid shaft is arranged between the needle shaft and the pressure adjusting shaft. The first and second pipelines are formed in the valve body. The first and second fuel chambers are formed in the bottom of the needle body to be vertically separated from each other. The fifth pipeline is formed in the needle shaft, and the sixth pipeline is connected to a groove of the needle shaft. The elastic member is elastically supported to the needle shaft and the valve body.

Description

Two Kind Fuel Injection Device Providing Multiple Injection for 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 an integrated structure that can be used in combination with a mechanical injection drive structure and an electric injection drive structure. Fuel supplied through different pipelines is improved to be multi-stage in micropilot injection, main injection, and after injection depending on the driving position of the needle shaft, thereby minimizing the installation space for the fuel injection device in an engine using dual fuel. The engine's performance is higher.

In general, a diesel engine using dual fuel is equipped with a fuel injection device driven by a needle shaft mechanically and a fuel injection device powered by an electric drive. Accordingly, it takes up a lot of mounting space, it is difficult to secure sufficient mounting space, and if necessary, relocation of peripheral components is also required to secure the mounting space.

In addition, a diesel engine using a double fuel injection device employs a method in which a micropilot injection and a main injection are simultaneously performed and self-ignited in a compressed air cylinder. At this time, since the mixing time of the compressed air and fuel until the self ignition in the state where the micro pilot injection and the main injection are performed at the same time is absolutely insufficient, the occurrence of smoke is excessive due to unstable combustion and fuel. There was a problem in that the combustion performance could not be improved and nitrogen oxides (NOx) could not be reduced.

The present invention is improved to an integrated structure that can be used in combination with the mechanical injection drive structure and the electric injection drive structure to solve the above problems, with the fuel supplied through the different conduits at the drive position of the needle shaft Dual pilot with multi-stage injection function for dual fuel engines, which improves the performance of the micropilot injection and main injection in multiple stages, minimizing the installation space for fuel injection systems and increasing engine performance in dual fuel engines. The purpose is to provide an injector.

In the present invention, the needle body is fixedly connected to the lower end of the valve body is provided with the first and second fuel inlet and the first and second injection port is formed; A needle shaft accommodated in the valve body and the needle body, and a pressure regulating shaft engaged with the inner surface of the valve body in a state disposed above the needle shaft; A solenoid shaft disposed between the needle shaft and the pressure adjusting shaft; First and second conduits formed in the valve body to connect the first and second fuel inlets and the first and second recesses; First and second fuel chambers formed at a lower portion of the needle body at intervals in the vertical direction; A fifth conduit formed in a needle shaft to communicate with the first fuel chamber and the first recess; A sixth conduit formed downward from an upper surface of the needle shaft and connected to a second recess of the needle shaft; There is provided a dual fuel injection device having a multi-stage injection function for a dual fuel engine, consisting of; an elastic member, the upper and lower ends are elastically supported on the needle shaft and the valve body in a state disposed between the valve body and the needle shaft.

In addition, there is provided a dual fuel injection device having a multi-stage injection function for a dual fuel engine mounted between the solenoid shaft and the valve body in a state in which the solenoid surrounds the solenoid shaft.

In addition, a lower fuel injection device having a multi-stage injection function for a dual fuel engine having a fourth recess is formed on the lower surface of the solenoid shaft to communicate with a sixth conduit opening to the upper surface of the needle shaft.

In addition, the inner surface of the needle body is provided with a dual fuel injection device having a multi-stage injection function for the dual fuel engine, the key groove is formed in the longitudinal direction, the needle shaft is protruded to form a key coupled to the key groove.

In addition, the valve body has a stepped portion formed on the inner circumferential surface so that the lower end of the elastic member is elastically supported, and the needle shaft has a multistage injection function for the dual fuel engine having a stepped portion formed on the inner circumferential surface so that the upper end of the elastic member is elastically supported. One dual fuel injection device is provided.

As such, the present invention is improved to an integrated structure that can be used by using a mechanical injection drive structure and an electric injection drive structure, and together with the fuel supplied through different pipelines, the micropilot injection, The main injection and post injection are improved to have multiple stages, minimizing the installation space for the fuel injection device in the dual fuel engine, suppressing smoke and generating NOx in the diesel engine, and burning You can expect the effect to improve performance.

1 is a cross-sectional view showing a dual fuel injection unit having a multi-stage injection function for a dual fuel engine according to the present invention.
FIG. 2 is a sectional view showing the main parts of FIG. 1. FIG.
3 is a cross-sectional view illustrating AA of FIG. 2.
4A to 4C are cross-sectional views showing mechanical driving in a dual fuel injection device having a multi-stage injection function for a dual fuel engine according to the present invention. FIG. 4A shows a micropilot injection state, and FIG. 4B shows a main injection state. 4c shows the post-injection state.
5A and 5B are sectional views showing electric driving in a dual fuel injection device 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, and FIG. 5B is a micro pilot injection. It shows the state.

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 device having a multi-stage injection function for a dual fuel engine according to the present invention, and FIG.

As shown, the dual fuel injection device 10 according to the present invention is a valve body 12, a fixed cap 14 fixedly coupled to the lower end of the valve body 12, and the inner surface of the fixed cap 14 A needle body 16 fixedly connected to the bottom surface of the valve body 12 by a coupling structure engaged with the needle structure, and a needle shaft 18 accommodated in a slidable state over the valve body 12 and the needle body 16; And a pressure regulating shaft 20 accommodated and coupled within the valve body 12 in a state disposed above the needle shaft 18, and a solenoid shaft disposed between the pressure regulating shaft 20 and the needle shaft 18. And a solenoid 24 provided in a state surrounding the solenoid shaft 22, and first and second injection holes 26 and 28 formed in the needle body 16.

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

In addition, the first and second conduits 34 and 36 are formed downward in the valve body 12 so as to communicate with the first and second fuel inlets 30 and 32, respectively. And the second conduits 34 and 36 have a structure in which communication is connected with the third and fourth conduits 38 and 40 corresponding to the needle bodies 16, respectively.

The third and fourth conduits 38 and 40 formed in the needle body 16 communicate with the first and second recesses 42 and 44 respectively formed along the inner circumferential surface of the needle body 16. Leads to. At this time, the first recess 42 is located above the second recess 44.

A third groove portion 46 corresponding to the first groove portion 42 of the needle body 14 is formed below the needle shaft 18, and the first groove portion 42 and the third groove portion are formed. When the 46 faces each other, the space 48 is formed.

The first and second fuel chambers 50 and 52 are formed at positions spaced downwardly from the third recess 46 of the needle shaft 18, wherein the first and second fuel chambers 50 and 52 are The fifth conduit 54 is disposed in the needle shaft 18 so that the first fuel chamber 50 and the third recess 46 of the needle shaft 18 communicate with each other. It is. At the same time, a sixth conduit 56 is formed in the needle shaft 18 to connect the upper surface with the second fuel chamber 52 of 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. Stepped portion 60 is formed on the inner surface of the valve body 12 so that the lower end of the elastic member 58, the inner surface of the needle shaft 18 so that the upper end of the elastic member 58 can be elastically supported. Stepped portion 62 is also formed. That is, the upper end of the elastic member 58 is elastically supported on the needle shaft 18 and the lower end is elastically supported on the valve body 12.

The solenoid shaft 22 is provided in the valve body 12 and disposed so that the lower surface thereof is placed on the upper surface of the needle shaft 18. In addition, a fourth recess 64 is formed on a lower surface of the solenoid shaft 22 in a structure communicating with a sixth conduit 56 that opens to the upper surface of the needle shaft 18. The solenoid 24 is mounted between the solenoid shaft 22 and the valve body 12 so as to surround the solenoid shaft 22.

The upper portion of the solenoid shaft 22 is provided in the valve body 12 in a state in which the pressure adjusting shaft 20 is disposed, the pressure adjusting shaft 20 has a structure that is fastened in a spiral with the valve body 12. have. In addition, the pressure adjusting shaft 18 drawn out from the valve body 12 has a structure in which a nut 66 for preventing separation of the pressure adjusting shaft 18 is tightened.

The pressure adjusting shaft 20 is, for example, to adjust the elastic force of the elastic member 58, first release the tightening fastening of the nut 66 and then rotate the pressure adjusting shaft 20 in the tightening or releasing direction. When the position is moved in the vertical direction, the solenoid shaft 22 and the needle shaft 18 also move in a state in which the elastic member 58 contracts or relaxes according to the moving direction of the pressure adjusting shaft 20, thereby changing the elastic force variably. It can be adjusted.

In Figure 3 is a plan cross-sectional view showing A-A of FIG. As shown in the figure, a key groove 68 is formed in a longitudinal direction on one inner surface 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 rotation of the needle shaft 18 in accordance with the lifting and lowering. This prevents the fuel supplied to the first fuel chamber 50 and the second dye chamber 52 from mixing with each other.

For reference, since the first injection hole 26 is an injection hole for injecting high-quality fuel, the first injection hole 26 is formed to be smaller than the inner diameter of the second injection hole 28. By being injected into the first injection hole 26, the key 70 and the key groove 68 are formed to prevent the needle shaft 18 from rotating in order to prevent the first injection hole 26 from being blocked. (See Fig. 2)

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

First, in a state before the supply of fuel, that is, the state in which the needle shaft 18 is positioned at the top, as shown in FIG. 2, the first and second fuel chambers 50 and 52 of the needle shaft 18 are first and second. It is located high from the 2nd injection port 26 and 28, respectively, and the 1st and 2nd fuel chambers 50 and 52 will be in the state blocked by the inner surface of the needle body 16. As shown in FIG.

When fuel is supplied through the first and second fuel inlets 30 and 32 in the above state, as shown in FIG. 4A, the fuel supplied to each of the valve body 12 and the needle body 16 is removed. The first and second grooves 42 and 44 are collected along the first to fourth pipe lines 34, 34, 38, and 40.

At this time, the fuel collected in the second recess 44 is along the sixth conduit 56 of the needle shaft 18 through the second fuel chamber 52 and the fourth recess 64 of the solenoid shaft 22. Will be gathered together.

Then, as the pressure of the fuel collected in the fourth groove portion 64 gradually rises as described above, the elastic force of the elastic member 58 is overcome, resulting in pressing the needle shaft 18 downward.

When the needle shaft 18 is lowered as described above, the first fuel chamber 50 is in communication with the first injection hole 26, so that the fuel present in the first fuel chamber 50 is first The micro pilot injection is performed through the injection hole 26. At this time, the second fuel chamber 52 is located at a position higher than that of the second injection hole 28, so that main injection through the second injection hole 28 is not performed.

In addition, when the first fuel chamber 50 further descends past the first injection hole 26 due to the continuous lowering of the needle shaft 18, fuel injection through the first injection hole 26 is stopped.

As described above, when the needle shaft 18 is continuously lowered and positioned at the lowermost end, as illustrated in FIG. 4B, the second fuel chamber 52 meets in communication with the second injection hole 28, and the second fuel chamber The fuel existing in the 52 is in a state of main injection through the second injection hole 28. At this time, the first injection hole 26 is blocked by the needle shaft 18 as shown in the figure to maintain the state that the injection through the first injection hole 26 is stopped.

When the fuel supply pressure is lowered by the injection as described above, the elastic force of the elastic member 58, which is compressed due to the lowering of the needle shaft 18, increases the needle shaft 18 while the fuel supply pressure overcomes the fuel supply pressure. Accordingly, when the needle shaft 18 is raised, the second fuel chamber 52 is out of the second injection hole 28 and main injection through the second injection hole 28 is stopped.

In addition, when the first fuel chamber 50 meets again in communication with the first injection hole 26 as shown in FIG. 4C due to the continuous rise of the needle shaft 18, the first fuel chamber 50 The fuel present in the) is post-injected through the first injection hole (28).

Then, the needle shaft 18 is placed in the state of FIG. 2 due to the continuous rising of the needle shaft 18, thereby completing the fuel injection supply.

That is, in the present invention, the micropilot injection, main injection, and post injection are performed according to the lifting position of the needle shaft 18 together with the new operation structure of the needle shaft 18, so that the mixing time of air and fuel in the diesel engine is improved. By ensuring enough, it becomes possible to raise the stable combustion and combustion performance, to minimize the generation | occurrence | production of smoke, and to suppress generation | occurrence | production of nitrogen oxides (NOx). This improves engine performance.

Meanwhile, FIGS. 5A and 5B are cross-sectional views illustrating electric driving in a dual fuel injection device having a multi-stage injection function for a dual fuel engine according to the present invention. In FIG. 5A, the fuel is supplied, and in FIG. It shows the pilot injection state.

First, in the state where the needle shaft 18 is located at the top, as shown in FIG. 2, the first and second fuel chambers 50 and 52 of the needle shaft 18 are formed of the first and second injection holes 26 and 28. ), And the first and second fuel chambers 50 and 52 are blocked by the inner surface of the needle body 16.

When fuel is supplied from the first fuel inlet 30 in the above state and the fuel is stopped through the second fuel inlet 32, the needle shaft 18 is not driven as shown in FIG. 5A. Will not. As such, when a problem occurs in supplying fuel through the second fuel inlet 32, the solenoid 24 operates.

Then, the needle shaft 18 is forcibly lowered by the magnetic field formed by the operation of the solenoid 24 so that the first fuel chamber 50 communicates with the first injection hole 26 as shown in FIG. 5B. By meeting the micro pilot injection is made.

When the operation of the solenoid 24 is stopped while the fuel supply pressure is lowered due to the injection as described above, the elastic force of the compressed elastic member 58 due to the lowering of the needle shaft 18 overcomes the fuel supply pressure. The shaft 18 is raised, and the needle shaft 18 is finally placed in the state of FIGS. 5A and 2 to finish the fuel injection supply.

As mentioned above, although this invention demonstrated that micro pilot injection, main injection, and after injection were made in multiple steps according to the moving position of the needle shaft 18, this invention is not limited by this. For example, when the needle shaft 18 is positioned at the lowermost position by changing the positions of the first and second fuel chambers 50 and 52, the micro-pilot injection and main injection are simultaneously performed, and the needle shaft 18 is operated without post injection. Also included in the present invention is a structure that moves to the top to end the fuel supply.

10: dual fuel injection device 12: valve body
14: fixed cap 16: needle body
18: needle shaft 20: pressure control shaft
22: solenoid 26: first injection hole
28: 2nd injection hole 30: 1st fuel injection hole
32: second fuel inlet 34: the first pipeline
36: second pipeline 38: third pipeline
40: fourth pipeline 42: first groove portion
44: second groove portion 46: third groove portion
48: space 50: first fuel chamber
52: second fuel chamber 54: fifth pipeline
56: sixth pipeline 58: elastic member
60, 62: stepped portion 64: fourth groove portion
66: nut 68: keyway
70: key

Claims (5)

A needle body 16 fixedly connected to a lower end of the valve body 12 having the first and second fuel injection ports 30 and 32 and having first and second injection holes 26 and 28 formed therein; ;
The needle shaft 18 accommodated in the valve body 12 and the needle body 16, and the pressure control shaft 20 is engaged with the inner surface of the valve body 12 in a state disposed on the needle shaft 18 );
A solenoid shaft 22 disposed between the needle shaft 18 and the pressure adjusting shaft 20;
First and second conduits (34, 36) formed in the valve body (12) to connect the first and second fuel inlets (30, 32) and the first and second recesses (42, 44);
First and second fuel chambers (50, 52) formed at a lower portion of the needle body (16) at intervals in the vertical direction;
A fifth conduit (54) formed in the needle shaft (18) for the first fuel chamber (50) to communicate with the first recess (46);
A sixth conduit 56 formed downward from an upper surface of the needle shaft 18 and connected to the second recess 44 of the needle shaft 18;
And an elastic member 58, the upper and lower ends of which are disposed between the valve body 12 and the needle shaft 18 and are elastically supported by the needle shaft 18 and the valve body 12; Dual fuel injection device with multi-stage injection function for fuel engine. The method of claim 1,
Dual fuel injection device having a multi-stage injection function for a dual fuel engine, characterized in that the solenoid 24 is mounted between the solenoid shaft 22 and the valve body 12 to surround the solenoid shaft (22).
The method of claim 2,
The lower surface of the solenoid shaft 22 has a fourth groove portion 64 is formed so as to communicate with the sixth conduit 56 which opens to the upper surface of the needle shaft 18 has a multi-stage injection function for a dual fuel engine. Dual fuel injection device provided.
The method of claim 3,
Dual fuel, characterized in that the inner surface of the needle body 16 is formed with a key groove 68 in the longitudinal direction, and the needle shaft 18 is formed with a key 70 is coupled to the key groove 68 protrudingly formed. Dual fuel injection device with multi-stage injection function for engine.
The method according to any one of claims 1 to 4,
The valve body 12 has a stepped portion 60 formed on the inner circumferential surface of the elastic member 58 so that the lower end of the elastic member 58 is elastically supported. Dual fuel injection device having a multi-stage injection function for a dual fuel engine, characterized in that the stepped portion (62) is formed.

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