KR101328757B1 - A two stage fuel injection valve for a diesel engine - Google Patents

Abstract

The present invention improves the combustion efficiency by increasing the injection pressure under low load conditions of the engine by adjusting the fuel injection pressure by injecting fuel in one or two stages according to the load condition of the engine, and through two-stage injection under the high load conditions of the engine. The present invention relates to a two-stage fuel injection valve for a diesel engine that can prevent a sudden increase in temperature and pressure in a combustion chamber.

The present invention as described above, the nitrogen in response to the rapid temperature and pressure rise in the combustion chamber that is generated by the injection of a large amount of fuel by instantaneous injection of a large amount of fuel by injecting the fuel divided into two stages sequentially It is effective in preventing the excessive generation of oxides, and it is possible to inject the same amount of fuel at a higher pressure at the same time, thereby improving the atomization of the fuel at low load conditions, and penetration By increasing the length, the fuel is better mixed with the intake air to produce a mixer suitable for combustion, thereby improving the combustion efficiency and reducing the exhaust gas such as fuel consumption and smog.

Fuel injection valve, injection needle, diesel engine, combustion chamber, injection needle height adjusting means

Description

A two stage fuel injection valve for a diesel engine

The present invention relates to a two-stage fuel injection valve for a diesel engine, and more particularly, to increase the injection pressure under low load conditions of the engine by controlling the fuel injection pressure by injecting fuel in one or two stages according to the load condition of the engine. The present invention relates to a two-stage fuel injection valve for a diesel engine capable of improving combustion efficiency and preventing a sudden increase in temperature and pressure in a combustion chamber through two-stage injection under high load conditions of an engine.

Hereinafter, a background art and a problem thereof will be described with reference to the accompanying drawings.

1 is a cross-sectional view for explaining a fuel injection valve for a general diesel engine.

Referring to FIG. 1, a conventional fuel injection valve 1 for a diesel engine includes a hollow portion 100 formed inside the valve body 10 to push the elastic member 13 to the hollow portion 100. The rod 12 is installed, and the nozzle body 15 is installed below the valve body 10.

A sliding hole 150 is formed at an inner central portion of the nozzle body 15, a high pressure chamber 151 is formed at a central portion of the sliding hole 150, and a seat surface 152 at a lower end of the sliding hole 150. ), An injection chamber 153 is formed at the lower end of the seat surface 152, and a plurality of injection holes 154 are formed from the injection chamber 153 to the outer circumferential surface of the nozzle body 15.

The needle valve 11 is slidably inserted into the sliding hole 150 of the nozzle body 15 configured as described above so that the upper end is supported by the lower end of the elastic member 13, and thus the lower surface of the needle valve 11 is provided. The injection chamber 153 can be opened and closed while being spaced or in contact with the seat surface 152.

In addition, the high pressure fuel supplied from the fuel pump (not shown) is supplied to the high pressure chamber 151 of the nozzle body 15 through the fuel injection hole 103 formed in the valve body 10, and the high pressure chamber ( When the pressure of the supplied fuel is greater than the force applied to the upper portion of the needle valve 11 by the elastic member 13 and the push rod 12, the lower surface of the needle valve 11 is separated from the seat surface 104. Then it is sprayed into the combustion chamber through the injection chamber 153 and the injection port 154. The upper side of the elastic member 13 is provided with a pressure adjusting screw 14 that can adjust the opening pressure by adjusting the elasticity of the elastic member.

Next, the operation of the conventional fuel injection valve for a conventional diesel engine configured as described above is as follows.

The fuel injection valve 1 for the conventional general diesel engine configured as described above includes a nozzle body in which the fuel supplied at high pressure by a fuel pump (not shown) is provided with the needle valve 11 through the fuel inlet 103. When supplied to the high pressure chamber 151 of 15), the needle valve 11 is driven by the fuel supplied at high pressure through the fuel inlet 103 due to the characteristic of the needle valve 11 is formed larger than the diameter of the lower end portion It is pushed in the direction of the push rod 12 to perform a sliding movement.

In addition, the push rod 12 is pushed by the needle valve 11 is raised in conjunction with the needle valve 11 to press the elastic member 13, thereby the elastic member 13 is in a compressed state Becomes

As described above, when the needle valve 11 is slid and moved up, the needle valve 11 is spaced apart from the sliding hole 150 seat surface 152 to provide fuel between the needle valve 11 and the seat surface 152. Is introduced, and the fuel introduced between the needle valve 11 and the seat surface 152 passes through the injection chamber 153 and is supplied into the combustion chamber through the injection hole 154.

In addition, due to the nature of the fuel pump (not shown), since the pressure of the supplied fuel is momentarily interrupted, the original restoring force of the compressed elastic member 13 is greater than the pressure of the fuel formed in the high pressure chamber 151, so that the push rod 12 Will descend. The needle valve 11 is also pushed down by the push rod 12 that is lowered as described above, so that the lower end of the needle valve 11 comes into close contact with the seat surface 152 so that the fuel is no longer injected. It will not be supplied into the combustion chamber through.

However, the fuel injection valve 1 for the conventional diesel engine as described above has the needle valve 11 raised and a plurality of injection ports 154 open at the same time, so that excessive fuel is injected at the initial stage of the injection of the fuel, and thus, in the combustion chamber There is a problem in that the temperature and pressure is rapidly increased to generate a large amount of nitrogen oxide exhaust gas, and during low load operation, the fuel injection pressure is low due to the low fuel injection pressure, resulting in poor combustion efficiency and poor fuel economy, and exhaust of smog, etc. There was a problem that the gas is increased.

Accordingly, an object of the present invention is to adjust the fuel injection pressure by injecting fuel in one or two stages according to the load condition of the engine, thereby improving the combustion efficiency by increasing the injection pressure in the engine under low load conditions, and high engine load conditions. In the second stage injection to provide a two-stage fuel injection valve for a diesel engine that can prevent the phenomenon of rapid temperature and pressure increase in the combustion chamber.

The present invention for achieving the above object, is formed in the inner central portion, the first sheet surface is formed in the lower end, the second sheet surface is formed in the center portion, the third sheet surface is formed in the upper end of the second sheet surface A hollow portion having a fourth sheet surface formed at an upper end of the third sheet surface; A needle chamber formed below the hollow part so as to be positioned above the first seat surface; A lower pressure portion communicating with the needle chamber and a central portion communicating with the central portion of the hollow portion such that the high-pressure fuel inlet is formed through the outer peripheral surface center portion in the lower portion direction; A lower injection hole communicating downwardly inclined toward an outer circumferential surface at a lower end of the hollow part; An upper injection hole communicating downwardly inclined toward an outer circumferential surface at a lower end of the hollow part to be positioned above the lower injection hole; And a pressure-reducing air pressure inlet formed inclined downward from the one side of the upper surface to the fourth seat surface so as to communicate with the fourth seat surface. The first seat surface and the lower surface are slidably fastened so as to selectively contact the first seat surface and the lower surface with the needle chamber, and a fuel supply passage having a predetermined height is formed in the direction from the lower surface to the upper surface, and from the outer circumferential surface to the fuel supply passage An injection needle through which a fuel supply port is formed to communicate with the needle chamber; A push rod slidably fastened to the hollow portion so that the seat surface is supported by the upper surface of the injection needle; An injection spring interposed between the push rod and the hollow to support the lower end by the upper surface of the seat surface; A spring sheet slidingly coupled to an upper end of an outer circumferential surface of the push rod to support an upper end of the injection spring; An internal pressure needle slidingly fastened to an upper end of the spring sheet so that the lower surface is supported by the upper surface of the push rod; And a communication part with a central portion of the pressure-reducing air pressure inlet and the high-pressure fuel inlet, and slidingly coupled to a hollow portion in which the second to fourth seat surfaces are positioned such that the lower end is supported by the upper surface of the spring sheet and introduced through the pressure-reducing air pressure inlet. Injection needle height control means for raising the upper end by the high pressure fuel introduced through the air pressure and the high pressure fuel inlet, and raising the lower end by the high pressure fuel introduced through the high pressure fuel inlet; It is to provide a two-stage fuel injection valve for a diesel engine, characterized in that consisting of.

Here, the injection needle height control means, a fastening slot formed by a certain height in the direction of the lower surface from the lower surface, the fuel inlet is formed in the direction of the fastening slot in the center of the outer peripheral surface to communicate with the fastening slot, the upper surface of the fastening slot From the upper surface to the fuel injection port is formed through, the fuel inlet is in communication with the central portion of the high-pressure fuel inlet, the lower surface is fastened to the fastening slot to the internal pressure needle to be supported by the upper surface of the spring seat, the fastening slot The upper surface of the inner pressing needle is spaced apart from the upper surface by a predetermined distance, the lower surface is the outer pressing needle which is fastened to the inner pressing needle sliding the fastening slot so as to be spaced apart from the second seat surface; A control needle for selectively opening and closing the fuel ejection port of the external pressurizing needle and slidingly fastened to the hollow part so as to be in close contact with the third seat surface; A control piston supported by the upper surface of the control needle and slidably fastened to the hollow portion to be in close contact with the fourth seat surface, the control piston having a spring insertion slot formed in a direction from the upper surface to the lower surface; And a control spring inserted into the spring insertion slot and having an upper end protruding outward from the spring insertion slot of the control piston so that the upper end is supported by a lower surface of the height adjustment bolt screwed to the upper end of the hollow part. have.

In addition, in the two-stage fuel injection valve for the diesel engine according to the present invention, an additional pressurizing air pressure inlet may be further formed in the hollow portion in which the upper end of the control piston is located at the other side of the upper surface of the valve body.

As described above, the two-stage fuel injection valve for the diesel engine according to the present invention is pushed upward by the high pressure fuel sequentially supplied to the needle chamber, the fuel supply port and the fuel supply passage through the high pressure fuel inlet. The lower injection hole and the upper injection hole are sequentially opened by the sliding needle, so that the fuel is not injected in a large amount by instantaneously dividing the fuel in two stages through the lower injection hole and the upper injection hole. There is an effect to prevent the excessive generation of nitrogen oxides due to rapid temperature and pressure rise in the combustion chamber generated by the injection of a large amount of fuel.

In addition, the two-stage fuel injection valve for the diesel engine according to the present invention, the combustion chamber is formed by the injection of the primary combustion through the lower injection port and the combustion chamber to form a temperature and pressure more suitable for combustion to the secondary through the upper injection port In order to reduce the smog exhaust gas by increasing the combustion efficiency of the injected fuel, and in the low load area of the engine, the air pressure, the high pressure fuel inlet, the fuel inlet, and the fastening slot are injected into the hollow part through the pressure reducing air inlet. After the sequential roughness, the injection needle height control means is operated by the high-pressure fuel ejected upwardly through the fuel injection port to limit the height at which the injection needle is slid and moved so that the upper injection hole remains closed. Only the lower injection hole is opened while fuel is injected through only the lower injection hole. This allows the same amount of fuel to be injected at a higher pressure at the same time, thereby improving atomization of the fuel at low load conditions, and increasing the penetration length so that the fuel mixes better with the intake air. By producing a mixer suitable for combustion, there is an effect of improving the combustion efficiency and reducing the exhaust gas such as fuel consumption and smog.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is an overall cross-sectional view for explaining a two-stage fuel injection valve for a diesel engine according to the present invention, Figure 3 is a cross-sectional view for explaining the flow of fuel of the two-stage fuel injection valve for a diesel engine according to the present invention, 4 is a cross-sectional view illustrating a process of raising the injection needle of the two-stage fuel injection valve for a diesel engine according to the present invention, FIG. 5 is a cross-sectional view illustrating a process of raising the internal pressure needle as the injection needle is raised, FIG. 6 Is a cross-sectional view for explaining the configuration of the head height control means.

2 to 6, the two-stage fuel injection valve for a diesel engine according to the present invention, the valve body 10, the injection needle 11, the push rod 12, the injection spring 13, the spring seat ( 14), the internal pressure needle 15, the injection needle height control means (16).

In the valve body 10 of the two-stage fuel injection valve for a diesel engine according to the present invention configured as described above, a hollow portion 100 is formed at an inner central portion, and a first seat surface is formed at a lower end of the hollow portion 100. A 101 is formed, a second sheet surface 102 is formed at the central portion of the hollow portion 100, a third sheet surface 103 is formed at an upper end of the second sheet surface 102, and The fourth sheet surface 104 is formed at the upper end of the third sheet surface 103. In addition, the valve body 10 is formed with a needle chamber 105 in the lower portion of the hollow portion 100 to be located above the first seat surface 101, the needle chamber 105 and the lower end is in communication, The central portion is formed with a high-pressure fuel injection hole 106 penetrating from the outer circumferential center portion to the lower end portion so that the central portion communicates with the central portion of the hollow portion 100, and the lower furniture 107 is inclined downward from the lower end of the hollow portion 100 toward the outer circumferential surface thereof. ) Is formed in communication with each other, and the upper injection hole 108 is formed obliquely downward in the direction of the outer circumferential surface from the lower end of the hollow portion to be positioned above the lower injection hole 107, and the upper surface communicates with the fourth seat surface 104. In the fourth sheet surface 104 in the direction of the pneumatic inlet for pressure reduction 109 is formed through.

The injection needle 11 is slidably fastened so that the first seat surface 101 and the lower surface may be selectively adhered to the hollow portion 100 in which the needle chamber 105 is formed, and from the lower surface to the upper surface direction. The fuel supply passage 111 of a predetermined height is formed, and the fuel supply opening 112 is formed to communicate with the needle chamber 105 from the outer circumferential surface to the fuel supply passage 111 so as to vertically move along the hollow portion 100. As the slide is moved, the lower injection hole 107 and the upper injection hole 108 may be sequentially opened and closed.

The push rod 12 is slidably fastened to the hollow part 100 so that the seat surface 120 is supported by the upper surface of the injection needle 11.

The injection spring 13 is interposed between the push rod 12 and the inner circumferential surface of the hollow portion 100 so that the lower end is supported by the upper surface of the seat surface 120 of the push rod 12.

The spring seat 14 is slidingly fastened to an upper end of an outer circumferential surface of the push rod 12 to support an upper end of the injection spring 13.

The inner pressure needle 15 is slidably fastened to an upper end of the spring seat 14 so that the lower surface is supported by the upper surface of the push rod 12.

The injection needle height control means 16 is in communication with the central portion of the pressure-reducing air pressure inlet 109 and the high-pressure fuel inlet 106, and the second sheet so that the lower end is supported by the upper surface of the spring sheet 14. Sliding and fastening to the hollow portion 100, the surface 102, the third seat surface 103, the fourth seat surface 104 is located, the air pressure and high-pressure fuel inlet introduced through the pressure-reducing air inlet 109 ( The upper end is raised by the high pressure fuel introduced through the 106, and the lower end is raised by the high pressure fuel introduced through the high pressure fuel inlet 106 to control the height of the injection needle 11. .

Referring to the configuration of the injection needle height control means 16 as described above in more detail as follows.

The injection needle height control means 16 of the two-stage fuel injection valve for a diesel engine according to the present invention as described above, the external pressure needle 160, the control needle 161, the control piston 162 and the control spring 163. It consists of.

The external pressure needle 160 of the injection needle height control means 16 according to the present invention configured as described above, the fastening slot 160a of a predetermined height is formed in the direction of the upper surface from the lower surface, the fastening slot 160a The fuel inlet 160b penetrates through the center of the outer peripheral surface of the external pressure needle 160 in the direction of the fastening slot 160a, and the upper side of the external pressure needle 160 on the upper surface of the fastening slot 160a. The fuel inlet 160c is formed through the surface, and the fuel inlet 160b communicates with the central portion of the high-pressure fuel inlet 106, and the lower surface of the external pressure needle 160 is connected to the upper surface of the spring seat 14. The fastening slot 160a is slidably fastened to the inner pressure needle 15 so as to be supported by the fastening slot 160a, and the upper surface of the fastening slot 160a is spaced apart from the upper surface of the inner pressure needle 15 by a predetermined distance, and the external pressure needle 160 is fixed. Bottom surface) is spaced apart from the second seat surface 102 by a predetermined distance. So that the retaining slot (160a) is preferably fastened to the sliding inside the pressure needle (15).

The control needle 161 selectively opens and closes the fuel jet port 160c of the external pressure needle 160 and an upper portion of the external pressure needle 160 to be in close contact with the third seat surface 103. Sliding and fastening to the hollow portion 100 to be located in.

The control piston 162, the lower surface is supported by the upper surface of the control needle 161, the fourth seat surface 104 and the lower surface is selectively fastened to the hollow portion 100 to be in close contact with the lower surface. The spring insertion slot 162a is formed in the direction from the upper surface to the lower surface.

The control spring 163 is inserted into and fastened to the spring insertion slot 162a, and the upper end protrudes to the outside of the spring insertion slot 162a of the control piston 162 to screw the upper end of the hollow part 100. The upper end is supported by the lower surface of the height adjustment bolt 17.

Again, referring to Figures 2 to 6 will be described the operation of the two-stage fuel injection valve for a diesel engine according to the present invention.

2 to 6, first, in order to inject fuel using a two-stage fuel injection valve for a diesel engine according to the present invention, first by operating a fuel injection pump (not shown) connected to the fuel injection pump The high pressure fuel is supplied into the two-stage fuel injection valve for the diesel engine according to the present invention through the fuel inlet 106.

The high pressure fuel supplied as described above is supplied into the needle chamber 105 through the high pressure fuel inlet 106, and the high pressure fuel supplied into the needle chamber 105 supplies the fuel of the injection needle 11. It is introduced into the fuel supply passage 111 through the sphere (112).

When the high pressure fuel is supplied into the fuel supply passage 111 of the injection needle 11 as described above, the lower surface of the injection needle 11 is pressurized by the pressure of the fuel supplied into the fuel supply passage 111. And the sliding movement along the hollow portion 100 is raised.

As described above, when the injection needle 11 is slid and moved by a predetermined height along the hollow part 100 by the pressure of the fuel supplied into the fuel supply passage 111 of the injection needle 11, the injection needle The lower injection hole 107 sealed by the lower end of the outer circumferential surface of 11 is opened, and high-pressure fuel is primarily injected through the lower injection hole 107.

The high pressure fuel is first injected through the lower injection hole 107 as described above, and then the injection needle 11 is hollowed by the pressure of the fuel supplied into the fuel supply passage 111 of the injection needle 11. When the upper injection hole 108, which is closed by the lower end of the outer circumferential surface of the injection needle 11, is slid and moved along the part 100 to open, the lower injection hole 107 and the upper injection hole 108 are opened. Fuel is injected through.

At this time, the push rod 12 is pushed upward by the injection needle 11 which is slidably moved along the hollow part 100 to be moved upward along the hollow part 100, and the push rod 12 As the slide moves along the hollow portion 100, the injection spring 13 whose upper end is supported by the lower surface of the spring sheet 14 is pushed by the sheet surface of the push rod 12 is compressed.

In addition, as the push rod 12 is raised, the inner pressure needle 15 is also pushed upward by the push rod 12 to slide along the fastening slot 160a of the external pressure needle 160. .

That is, the inner pressing needle 15 may be moved by sliding by a distance L1 spaced apart from the upper surface of the fastening slot 160a and the upper surface of the inner pressing needle 15.

As described above, the two-stage fuel injection valve for the diesel engine according to the present invention is sequentially supplied to the needle chamber 105, the fuel supply port 112, and the fuel supply passage 111 through the high-pressure fuel inlet 106. The lower injection hole 107 and the upper injection hole 108 are sequentially opened by the injection needle 11 which is pushed upward by the high pressure fuel and is slidably moved, thereby allowing fuel to flow through the lower injection hole 107 and the upper injection hole 108. It is possible to prevent excessive generation of nitrogen oxide due to rapid temperature and pressure increase in the combustion chamber caused by instantaneous injection of a large amount of fuel by not spraying a large amount of fuel at a time by sequentially dividing the fuel into two stages. To help.

In addition, due to the influence of the fuel that is first injected through the lower injection hole 107, the combustion chamber forms a temperature and pressure suitable for combustion, thereby increasing the combustion efficiency of the fuel injected into the secondary through the upper injection hole 108. Smog emissions can be reduced.

In addition, the two-stage fuel injection valve for the diesel engine according to the present invention injects compressed air into the hollow portion 100 in which the control piston 162 is slidingly fastened through the pressure reducing air inlet 109 in the low load region of the engine. By raising the control piston 162, the control spring 163 is compressed by the control piston 162 as the control piston 162 is raised.

At this time, the high pressure fuel introduced into the fastening slot 160a of the external pressure needle 160 through the fuel inlet 160b of the external pressure needle 160 after being injected through the high pressure fuel inlet 106 is a fuel outlet ( It is discharged through the 160c to move the control needle 161 by sliding to raise it so that the lower end of the control needle 161 is in close contact with the third seat surface 103 and at the same time press the upper surface of the external pressure needle 160 By sliding the external pressure needle 160 to lower the lower surface of the external pressure needle 160 is in close contact with the second seat surface 102, the spring seat by the lower external pressure needle 160 14 is also slidingly moved to descend, the injection spring 13, the upper end supported by the lower surface of the spring sheet 14 is pressed by the spring sheet (14).

As the external pressure needle 160 is lowered as described above, the distance L1 between the upper surface of the fastening slot 160a of the external pressure needle 160 and the upper surface of the internal pressure needle 15 is pressurized by the external pressure. As the needle 160 is reduced by the lowered distance, the height at which the inner pressure needle 15 is raised is reduced by the distance by which the outer pressure needle 160 is lowered, thereby raising the push rod 12 and the injection needle 11. The height is also reduced by the distance the external pressure needle 160 is lowered.

Here, when the air pressure injected into the hollow part 100 through the pressure reducing air inlet 109 is low, it is insufficient to further inject air into the hollow part 100 through the additional pressure pneumatic inlet 18. To replenish the air pressure.

As described above, the two-stage fuel injection valve for the diesel engine according to the present invention includes the air pressure and the high pressure fuel inlet 106 and the fuel injected into the hollow part 100 through the pressure reducing air inlet 109 in the low load region of the engine. The injection needle height control means 16 is operated by the high pressure fuel ejected in the upward direction of the external pressure needle 160 through the fuel injection port 160c after passing through the inlet 160b and the fastening slot 160a sequentially. By restricting the height at which the injection needle 11 is moved by sliding, the upper injection hole 108 remains closed, and only the lower injection hole 107 is opened so that fuel is injected only through the lower injection hole 107. This allows the same amount of fuel to be injected at a higher pressure at the same time, thereby improving atomization of the fuel at low load conditions and increasing penetration length. This allows the fuel to mix better with the intake air to produce a mixer that is suitable for combustion, thereby improving combustion efficiency and reducing exhaust gases such as fuel economy and smog.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

1 is a cross-sectional view for explaining a fuel injection valve for a general diesel engine.

Figure 2 is an overall cross-sectional view for explaining a two-stage fuel injection valve for a diesel engine according to the present invention.

3 is a cross-sectional view for explaining the flow of fuel in a two-stage fuel injection valve for a diesel engine according to the present invention;

4 is a cross-sectional view illustrating a process of raising the injection needle of the two-stage fuel injection valve for a diesel engine according to the present invention;

5 is a cross-sectional view for explaining a process of raising the internal pressure needle as the injection needle is raised.

6 is a cross-sectional view for explaining the configuration of the head height control means.

<Description of the symbols for the main parts of the drawings>

10: valve body 11: injection needle

12: push rod 13: injection spring

14: spring seat 15: internal pressure needle

(16): injection needle height control means (17): height adjustment bolt

(18): Pneumatic inlet port for additional pressurization

Claims (3)

It is formed in the inner center portion, the lower end portion is formed with a first sheet surface, the central portion is formed with a second sheet surface, the upper end of the second sheet surface is formed with a third sheet surface, the upper end of the third sheet surface 4 a hollow portion in which the sheet surface is formed; A needle chamber formed below the hollow part so as to be positioned above the first seat surface; A lower pressure portion communicating with the needle chamber and a central portion communicating with the central portion of the hollow portion such that the high-pressure fuel inlet is formed through the outer peripheral surface center portion in the lower portion direction; A lower injection hole communicating downwardly inclined toward an outer circumferential surface at a lower end of the hollow part; An upper injection hole communicating downwardly inclined toward an outer circumferential surface at a lower end of the hollow part to be positioned above the lower injection hole; And a pressure-reducing air pressure inlet formed inclined downward from the one side of the upper surface to the fourth seat surface so as to communicate with the fourth seat surface. The first seat surface and the lower surface are slidably fastened so as to selectively contact the first seat surface and the lower surface with the needle chamber, and a fuel supply passage having a predetermined height is formed in the direction from the lower surface to the upper surface, and from the outer peripheral surface to the fuel supply passage An injection needle through which a fuel supply port is formed to communicate with the needle chamber; A push rod slidably fastened to the hollow portion so that the seat surface is supported by the upper surface of the injection needle; An injection spring interposed between the push rod and the hollow to support the lower end by the upper surface of the seat surface; A spring sheet slidingly coupled to an upper end of an outer circumferential surface of the push rod to support an upper end of the injection spring; An internal pressure needle slidingly fastened to an upper end of the spring sheet so that the lower surface is supported by the upper surface of the push rod; And In communication with the central portion of the pressure-reducing air inlet for pressure and the high-pressure fuel inlet, the air pressure introduced through the pressure-reducing air inlet by sliding fastening to the hollow portion in which the second to fourth seat surface is positioned so that the lower end is supported by the upper surface of the spring sheet. And an injection needle height control means configured to raise the upper end by the high pressure fuel introduced through the high pressure fuel inlet, and to raise the lower end by the high pressure fuel introduced through the high pressure fuel inlet to control the rising height of the injection needle. Two-stage fuel injection valve for a diesel engine, characterized in that configured. The method of claim 1, The injection needle height control means, A fastening slot formed at a predetermined height in a direction from a lower surface to a top surface, and a fuel inlet is formed in a direction of a fastening slot in a central portion of the outer circumferential surface so as to communicate with the fastening slot, and a fuel ejection hole is formed from an upper surface of the fastening slot to an upper surface of the fastening slot; The fuel inlet is in communication with the central portion of the high-pressure fuel inlet, the lower surface of the fastening slot is fastened to the internal pressure needle so that the fastening slot is supported by the upper surface of the spring seat, the upper surface of the fastening slot is the upper surface of the internal pressure needle An outer pressurizing needle spaced apart from each other by a predetermined interval, and a lower surface of the lower pressurizing needle slidingly fastened to the inner pressurizing needle so as to be spaced apart from the second seat surface by a predetermined distance; A control needle for selectively opening and closing the fuel ejection port of the external pressurizing needle and slidingly fastened to the hollow part so as to be in close contact with the third seat surface; A control piston supported by the upper surface of the control needle and slidably fastened to the hollow portion to be in close contact with the fourth seat surface, the control piston having a spring insertion slot formed in a direction from the upper surface to the lower surface; And And a control spring inserted into the spring insertion slot and having an upper end protruded to the outside of the spring insertion slot of the control piston so that the upper end is supported by a lower surface of the height adjustment bolt screwed to the upper end of the hollow portion. 2-stage fuel injection valve for diesel engine. The method of claim 2, A two-stage fuel injection valve for a diesel engine, characterized in that the additional pressure inlet for additional pressure is formed further through the hollow portion in which the upper end of the control piston is located on the other side of the upper surface of the valve body.

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