KR20040012819A - Fuel injector - Google Patents

Abstract

In the fuel injector in which the injector body 2 is equipped with the fuel injection control magnetic valve 4 provided with the magnet unit 6 comprised as the several component assembled in the fixed sleeve 61, the outflow path 67B is Air trapped in the fixed sleeve 61 and trapped in the gaps of the components in the fixed sleeve 61 by the pressurized fuel sent to the magnet unit 6 flows out of the fixed sleeve 61 to be replaced with fuel. The trapped air present in the gap between the components in the magnet unit 6 of the magnetic valve 4 is quickly replaced with fuel at the start of operation, so that stable control of the injected fuel amount can be reliably established in a short time.

Description

Fuel Injector {FUEL INJECTOR}

As a fuel injector for directly injecting fuel into a cylinder of an internal combustion engine, such as in a common rail system, for example, a fuel injector of the type disclosed in Japanese Unexamined Patent Application Publication No. 7 (1995) -310621 Is known. The fuel injector communicates with the low pressure part of the control chamber of the injector body to remove the valve piston back pressure, applies a current to raise the nozzle needle to start fuel injection, and opens the magnetic valve. After a period of time has elapsed, the application of the current to the magnetic valve is stopped to interrupt the communication between the control chamber and the low pressure part so that a predetermined back pressure acts on the valve piston to press the nozzle needle to terminate fuel injection. It is.

The magnetic valve for fuel injection control, which is attached to the injector body and opened and closed by a control signal applied from the outside, includes a cylindrical fixed core in which an excitation coil is wound in a backflow tube and a fixed sleeve that functions as a housing. a core obtained by coaxially positioning and further fixing a bush to an inner surface of the fixing core.

As described above, the components installed inside the fixed sleeve are manufactured and assembled with a predetermined dimensional precision so that no gap is caused between adjacent components. In practice, however, there is a slight gap between components, and the air is filled immediately after assembly. For example, when the fuel injector in this state is installed in the cylinder, and when injecting fuel, the air in the gap is gradually replaced by the fuel as the temperature of the fuel and the magnetic valve rises with the start of operation. However, until the gap is completely filled with fuel, the fact that air remains in the gap does not result in sufficient valve closing force. As a result, the amount of variation in the suction / repulsion action of the armature acted upon the on-off of the current supply to the magnetic valve used to control the communication state between the control chamber and the low pressure part. Fluctuations are caused. This causes a problem that fluctuations occur in the speed of the internal combustion engine because the amount of injected fuel cannot be stably controlled immediately upon installation of the injector. One way to avoid this problem is to run a test run until the trapped air escapes, but this requires unnecessary running time and fuel consumption, which presents another problem, inefficiency.

It is an object of the present invention to provide a fuel injector capable of overcoming the above problems of the prior art.

Another object of the present invention is to provide a fuel injector that enables stable injection operation immediately after installation.

Another object of the present invention is to provide a fuel injector that does not require unnecessary operating time.

Another object of the present invention is to provide a fuel injector that enables efficient fuel injection operation.

The present invention relates to a fuel injector for directly injecting fuel into a cylinder of an internal combustion engine.

1 is a cross-sectional view showing an embodiment of the present invention.

2 is an enlarged cross-sectional view of the magnet unit of the magnetic valve shown in FIG. 1;

FIG. 3 is a cross-sectional view showing enlargement of the core portion of the magnet unit shown in FIG. 2. FIG.

4 is a cross-sectional view showing an essential part of another embodiment of the present invention.

Fig. 5 is a front view showing, in cross section, the right half of an exciting coil of another embodiment of the present invention;

FIG. 6 is a view for explaining oiltight sealing in the case where the excitation coil shown in FIG. 5 is configured in the fixed core. FIG.

7 is a front view showing, in cross section, the right half of an exciting coil of another embodiment of the present invention;

FIG. 8 is a view for explaining oiltight sealing when the excitation coil shown in FIG. 7 is configured in a fixed core. FIG.

9 is a cross-sectional view of a core portion illustrating another embodiment of the present invention.

10 is a cross-sectional view showing an essential part of another embodiment of the present invention.

FIG. 11 is a perspective view of the sleeve shown in FIG. 10. FIG.

12 is a perspective view of the fixing core shown in FIG. 10.

FIG. 13 is a perspective view of the backflow tube shown in FIG. 10. FIG.

One feature of the present invention is:

The injector body is provided with a magnetic valve for fuel injection control having a hollow cylindrical fixed core fixed in a fixed sleeve and a magnet unit configured as a bush fixed in a central hollow of the fixed core, wherein the magnetic unit comprises a nozzle needle. In the fuel injector is installed between the control chamber and the low pressure portion for accumulating the high pressure fuel for controlling the rising operation of the, the high pressure fuel in the control chamber flows out to the low pressure portion through the bush when the magnetic valve is opened,

A hermetic seal is provided between the components contained in the fixed sleeve to prevent the high pressure fuel in the control chamber from penetrating into the gaps between the components.

Other features of the present invention are:

A fuel injector having an injector body equipped with a magnetic valve for fuel injection control having a magnet unit configured as a plurality of components assembled in a fixed sleeve,

The air trapped in the gap of the components in the fixed sleeve by the pressurized fuel sent to the magnet unit constitutes an outflow path that flows out of the fixed sleeve and is replaced by fuel.

When operating the fuel injector in a state where air is trapped in the gap in the fixed sleeve, pressurized fuel flows into the gap, and the pressure of the pressurized fuel quickly drives the trapped air through the outflow passage, instead of the trapped air. Fill the gap with fuel. Thus, stable control of the injected fuel amount can be reliably established within a short time immediately after installation of the injector.

BRIEF DESCRIPTION OF DRAWINGS To describe the present invention in more detail, it will be described with reference to the accompanying drawings.

1 is a cross-sectional view showing an embodiment of the present invention. Reference numeral 1 denotes a fuel injector used in a common rail system for injecting fuel in a diesel engine. The fuel injector 1 is provided in the cylinder of the internal combustion engine (not shown) in order to inject | pour a predetermined amount of the high pressure fuel supplied from the common rail (not shown) in a cylinder at predetermined time. It comprises an injector body 2 equipped with a magnetic valve 4.

The injector body 2 is equipped with the hollow body 23 which has the injector body 2 which the valve piston 21 slides. The hollow body 23 has a nozzle body 26 whose end is connected to the valve piston 21 as a nozzle orifice 25 and is closed by a tip of the nozzle needle 24. It is connected.

The hollow body 23 is formed with a hollow accessory 28 surrounding an inlet coupling 27 connected to a high pressure fuel supply pump (not shown). Fuel enters the fuel reservoir 29 through an internal passageway, and the nozzle body 26 is formed with a shoulder section 30 on which pressurized fuel in the fuel reservoir 29 acts. The nozzle spring 31 acts to press the valve piston 21 and the nozzle needle 24 downward.

Therefore, when the nozzle piston 24 is held at the position where the valve piston 21 is pressed downward to compress the nozzle spring 31 and close the nozzle orifice 25 of the nozzle body 26, the fuel injector 1 Fuel is not injected. When the force of the nozzle spring 31 moves the valve piston 21 upwards to hold the nozzle needle 24 in a position where the nozzle orifice 25 is open, fuel is supplied to the fuel injector 1. Sprayed by

The hollow body 23 has a head 33 configured with a downward facing drain chamber 32 extending coaxially with the axial groove 22 in the axial direction of the hollow body 23. Formed. The head 33 is formed together with the control chamber 37 in communication with the radial feed passage 34 and the axial drain passage 35. The feed passage 34 is in communication with the inlet coupling 27 through the radial passage 36 in the hollow body 23.

The fuel reservoir 29 is supplied with high pressure fuel using the passage 38. The high pressure fuel is also supplied to the control chamber 37, but as will be described later, when the drain passage 35 is in communication with the fuel low pressure portion by the magnetic valve 4, the fuel of the control chamber 37 The pressure is lower than the fuel pressure of the fuel reservoir 29. The upper surface of the valve piston 21 is formed to have a larger area than the upper surface of the shoulder portion 30, and therefore, the drain passage 35 is closed by the magnetic valve 4 so that the control chamber 37 has a high pressure. When filled with fuel, the nozzle needle 24 is held in a position to close the nozzle orifice 25 so that fuel is not injected.

On the other hand, when the magnetic valve 4 is opened, the fuel pressure of the control chamber 37 flows out through the drain passage 35 to the low pressure part, and the fuel pressure of the control chamber 37 is reduced by the fuel reservoir 29. The fuel injector is executed by retracting so that the nozzle needle 24 is maintained at a position to open the nozzle orifice 25 because it is lower than the fuel pressure.

The magnetic valve 4 for controlling the fuel pressure of the control chamber 37 for controlling the start and end of fuel injection is integrally formed with the injector body 2. The magnetic valve 4 comprises a magnet unit 6 shown in an enlarged sectional view of FIG. 2. The magnet unit 6 comprises a backflow tube 62 and a fixed core 63 located in the fixed sleeve 61, with an excitation coil 64 configured in the fixed core 63. The O-ring 65 is configured between the fixed sleeve 61 and the backflow tube 62 to form a structure such that fuel does not leak out from between the fixed sleeve 62 and the backflow tube 62.

A drain connector 62A for connecting with the fuel tank is integrally formed with the backflow tube 62. The axial hole 66 of the fixing core 63 is provided with a bush 67 having a small hole 67A formed at one end thereof. The bush 67 is attached through the fixing core 63 so that its small hole 67A and the drain connector 62A are coaxial. Thus, the backflow tube 62, the fixing core 63 and the bush 67 are installed coaxially in the fixing sleeve 61. The components installed in the fixed sleeve 61 in the manner described above are manufactured and assembled with a predetermined dimensional accuracy so that no gap is formed between adjacent components.

A disk-shaped armature 41 made of magnet is provided so as to face the fixed core 63 in the magnet unit 6, and a ball 42 (Fig. 1) operating as a valve body is It is held at the tip of the columnar portion 41A extending integrally from the armature 41. The armature 41 is pressed downward by the force of the valve spring (not shown), and forms the structure in which the ball 42 presses on the open end of the drain passage 35 to seal the drain passage 35.

Therefore, when the magnet unit 6 is not energized, the open end of the drain passage 35 is sealed by the ball 42, whereby the control chamber 37 is filled with high pressure fuel, and as a result, the valve piston 21 causes the nozzle needle 24 to close the nozzle orifice 25 so that no fuel is injected.

When the magnet unit 6 is energized, the armature 41 overcomes the force of the valve spring and retracts onto the magnet unit 6 such that the ball 42 is separated from the open end of the drain passage 35 and the control chamber The high pressure fuel in 37 flows out to the low pressure portion through the bush 67 and the drain connector 62A, and fuel is injected due to the pressure drop in the control chamber 37.

When the energization of the magnet unit 6 is stopped, the nozzle needle 24 returns to the position which closes the nozzle orifice 25 again, and fuel injection is complete | finished.

However, in the magnetic valve 4, a gap G1 occurs at the contact surface between the backflow tube 62 and the fixed core 63 due to the surface roughness and the assembly of the two components, and a slight gap ( G2 and G3 are formed between the fixing sleeve 61 and the fixing core 63 and between the fixing core 63 and the bush 67 due to the dimensional error occurring in the manufacturing process.

In the initial stage following the assembly of the magnetic valve 4, these gaps G1-G3 are filled with air. Therefore, if the fuel injector 1 should be operated at this stage, the difference in the damping forces of the air and fuel in the gap G1-the gap G3 is until the gap is completely filled with fuel, and the control chamber The amount of variation in the suction / repulsion action of the armature 41 operated in response to the on-off of the supply of current to the magnetic valve 4 used to control the communication state between the 33 and the low pressure portion. Will cause a change. As a result, it will generate a state in which it becomes impossible to perform stable control on the amount of injected fuel immediately after installation of the fuel injector 1. In order to avoid such a problem, the sealing members S1 and S2 are provided in the fixing sleeve 61 and the bush 67 to provide an oiltight seal so that fuel does not penetrate into the fixing sleeve 61.

3 is a cross-sectional view showing in detail an enlargement of the core portion of the unit shown in FIG. 2. The oiltight seals constituted by the fixing sleeve 61 and the bush 67 will be described with reference to FIG. 3.

An annular groove 61B is formed in the circumferential direction on the inner circumferential surface 61A of the fixing sleeve 61, and the sealing member S1 is provided in the annular groove 61B to be fixed. A hermetic seal is constructed between the sleeve 61 and the fixed core 63. Further, an annular groove 67C is formed on the outer circumferential surface 67B of the bush 67 in the circumferential direction, and the other sealing member S2 is provided in the groove 67C to provide the bush 67 with the bush 67. A hermetic seal is constituted between the fixed cores 63. The sealing members S1 and S2 are both formed as an annular member composed of a resin member having elasticity. Therefore, when the fixing core 63 is installed in the fixing sleeve 61, the sealing members S1 and S2 are in elastically forced contact with the associated wall of the fixing core 63 so that the fixing core 63 and the exciting coil ( 64) to form a hermetic seal between them. As a result, the fuel to penetrate into the gap G4 from the side of the armature 41 can be prevented by the sealing members S1 and S2, and the fuel is prevented from penetrating into the gap G1 to the gap G3. can do. In addition, by providing the sealing members S1 and S2 so as to be located as far as possible toward the armature 41 side, it is possible to prevent almost all of the fuel from penetrating into the gaps G1 to G3.

As a result, when the communication state control of the control chamber 33 and the low pressure part is operated in response to the on-off of the supply of current to the magnetic valve 4, it is possible to effectively prevent the high pressure fuel from entering the fixed sleeve 61. Even if there is air trapped in the gaps G1 to G3, it is possible to control a change in the amount of variation in the suction / repulsion action of the armature so that the amount of fuel injected immediately after installation of the fuel injector 1 can be controlled. Enable stable control. It is worth noting that if the sealing members S1 and S2 are installed to be located as far as possible toward the armature 41 side, almost all of the fuel can be prevented from penetrating into the fixed sleeve 61.

4 is a cross-sectional view showing an essential part of another embodiment of the present invention. Here, the contact region C1 of the fixed sleeve 61 and the fixed core 63 is formed of a taper contact portion 61C and a tapered contact portion 63A, respectively, and the fixed core 63 is fixed sleeve 61. By pressing down the upper part by swaging to form a hermetic seal in the linear contact region in the contact region C1 which prevents fuel penetration into the gap G2 from the armature 41 side, thereby sealing The structure which omits the member S1 is obtained.

In other words, the outer edge of the fixed core 63 is in forced contact with the fixed sleeve 61 along its inner circumferential surface to form a hermetic seal against an annular gap formed between the fixed sleeve 61 and the fixed core 63. The structure is made.

As shown in FIG. 2, the magnetic valve 4 constitutes a slight gap G4 between the fixed core 63 and the exciting coil 64 in addition to the gaps G1 to G3. The air trapped in the gap G4 causes the same problem as that caused by the air trapped in the gap G1 to the gap G3. If desired, these can be avoided by forming a hermetic seal between the fixed core 63 and the exciting coil 64.

5 and 6 show another embodiment in which a hermetic seal is formed between the fixed core 63 and the exciting coil 64. FIG. 5 is a front view showing the right half of the excitation coil 64 in cross section, and FIG. 6 is a view for explaining the oil-sealed state when the excitation coil shown in FIG. 5 is configured in the fixed core 63. In the embodiment shown in Fig. 5, the exciting coil 64 is covered by a coating layer 641 formed by molding with a coating material configured as a flexible resin material. In addition, the outer surface 641a and the inner surface 641b of the coating layer 641 are formed integrally with the sealing members S31 and S32 in an annular ridge member manner extending in cross section along an associated surface of a triangular shape. By being comprised, sealing member S31, S32 has appropriate elasticity as a sealing member.

Since the sealing members S31 and S32 are configured on the exciting coil 64 to have appropriate elasticity as the sealing member in the above-described manner, the exciting coil 64 can be attached to the fixed core 63 as shown in FIG. At this time, since the sealing members S31 and S32 are in elastic contact with the associated wall of the fixing core 63, the oil tight sealing is constituted between the fixing core 63 and the exciting coil 64. As a result, the fuel to penetrate into the gap G4 from the side surface of the armature 41 can be prevented by the sealing members S31 and S32, and the fuel can be prevented from penetrating into the gap G4. In addition, by configuring the sealing members S31 and S32 as far as possible toward the armature 41 side, it is possible to prevent almost all of the fuel from penetrating into the gap G4.

FIG. 7 shows a variation of the excitation coil 64 shown in FIG. In the embodiment of Fig. 7, the sealing coils S31 and S32 are replaced with the sealing members S41 and S42, which are formed integrally with each other in the manner of a hemispherical ridge member in cross section. 64 is different from that shown in FIG.

Since the sealing members S41 and S42 are configured on the exciting coil 64 so as to have appropriate elasticity as the sealing member in the above-described manner, the exciting coil 64 can be attached to the fixed core 63 as shown in FIG. At this time, since the sealing members S41 and S42 are elastically forced in contact with the associated wall of the fixing core 63, the oil tight sealing is constituted between the fixing core 63 and the exciting coil 64. As a result, the fuel to penetrate into the gap G4 from the side surface of the armature 41 can be prevented by the sealing members S31 and S32, and the fuel can be prevented from penetrating into the gap G4.

9 shows another embodiment of the present invention. Here, the fixed core 63 is covered with a coating layer 631 formed by molding with a coating material constituted as an elastic resin material. In addition, the outer surface 631a and the inner surface 631b of the coating layer 631 are formed and configured integrally with the sealing members S51 and S52 in an annular ridge member manner extending along a hemispherical related surface in cross section. As a result, the sealing members S51 and S52 have appropriate elasticity as the sealing member.

Since the sealing members S51 and S52 are configured on the fixing core 63 to have appropriate elasticity as the sealing member in the above-described manner, when the fixing core 63 is attached to the fixing sleeve 61, the sealing member S51 Since S52 is in elastically forced contact with the associated wall of the fixing core 63, a hermetic seal is constructed between the fixing core 63 and the fixing sleeve 61. As a result, the fuel to penetrate into the gap G1 to the gap G3 from the side surface of the armature 41 can be blocked by the sealing members S51 and S52, and the fuel is prevented from the gap G1 to the gap G3. Can be prevented from infiltrating

As is evident from the above, the fuel injector 1 is constituted by an oiltight seal between the components contained in the fixed sleeve, thereby preventing the high pressure fuel in the control chamber from penetrating into the gaps between the components, and thus, for example, fuel in the cylinder. When the injector 1 is installed and operated to inject fuel, suction / armature of the armature actuated in response to the on / off supply of current to the magnetic valve used to control the communication between the control chamber and the low pressure part. The fluctuation amount in the repulsion action is not changed for reasons that sufficient valve closing force cannot be obtained because of the air remaining in the gap. As a result, the injected fuel amount can be stably controlled immediately after installation of the fuel injector, and the variation of the internal combustion engine speed can be suppressed. Moreover, there is no need to continue the test run until the trapped air is discharged, so the efficiency is very high because no unnecessary running time or fuel consumption occurs.

10 shows the essential parts of another embodiment of a fuel injector according to the invention. Like the magnetic valve 4, the magnetic valve 104 shown in FIG. 10 is attached to the injector body 2 shown in FIG. 1 to constitute a fuel injector. The magnetic valve 104 includes a magnet unit 106. The magnet unit 106 includes a backflow tube 162 and a fixed core 163 located within the fixed sleeve 161, and an excitation coil 164 is configured within the fixed core 163. An O-ring 165 is configured between the fixed sleeve 161 and the backflow tube 162 to form a structure that prevents fuel from leaking out between the fixed sleeve 162 and the backflow tube 162.

A drain connector 162A for connecting with the fuel tank is integrally formed with the backflow tube 162. The axial hole 166 of the fixed core 163 is provided with a bush 167 having a small hole 167A formed at one end thereof. The bush 167 is attached through the fixing core 163 such that its small hole 167A and the drain connector 162A are coaxial. Thus, the backflow tube 162, the fixing core 163 and the bush 167 are installed coaxially in the fixing sleeve 161. The components installed in the fixed sleeve 161 in the manner described above are manufactured and assembled with a predetermined dimensional accuracy so that no gap is formed between adjacent components.

The disk-shaped armature 141 made of magnet is provided so as to face the fixed core 163 in the magnet unit 106, and a ball (not shown) which acts as a valve body extends integrally from the armature 141. It is held at the tip of the columnar portion 141A. The mechanism by which the armature 141 controls injection of fuel from the injector body is the same as that of the previous embodiment described with reference to FIG. 1.

However, in the magnet unit 106, a gap G5 occurs at the contact surface between the backflow tube 162 and the fixed core 163 due to the surface roughness and the assembly of the two components, and a slight gap G6 occurs. Due to the dimensional error occurring in the manufacturing process is formed between the fixed sleeve 161 and the fixed core 163. In addition, a slight gap G7 is formed between the bush 167 and the fixed core 163 due to the dimensional error occurring in the manufacturing process.

In the initial stages following assembly, these gaps G5, G6, G7 are filled with air. Therefore, immediately after operation of the fuel injector 101 immediately after assembly, the trapped air flows to quickly discharge the air trapped in the gaps G5, G6, and G7 to the outside of the magnetic valve 104 and replace it with fuel. Is formed in the bush 167.

11 is a perspective view of the bush 167. As can be seen in FIG. 11, the bush 167 has an outlet passage 167B, such as four round holes, at the same height as the height of the gap G5 between the backflow tube 162 and the fixing core 163. Is formed. Therefore, when the magnet unit 106 is energized to allow the high pressure fuel in the control chamber 137 to allow outflow to the low pressure portion through the bush 167 and the drain connector 162A, it acts on the gap G5. The fuel pressure may cause air trapped in the gaps G5, G6, and G7 to flow into the bush 167 through the outflow path 167B. As a result, the trapped air in the gaps G5, G6, G7 occurring in the magnetic valve 104 can be quickly discharged and replaced with fuel at the same time.

Although the outflow path 167B is formed in four positions, the number of positions is not limited to this, It may be one or more positions. In addition, its shape need not be round, and a rectangular or other desired shape can be formed at an appropriate position and at an appropriate size.

In addition, an auxiliary passage that improves the passage of the trapped air is formed in the fixed core 163 and the backflow tube 162 to further trap the air trapped in the magnetic valve 104 from the gaps G5, G6, and G7. It is possible to enable rapid discharge.

12 is a perspective view of the fixing core 163, and FIG. 13 is a perspective view of the backflow tube 162. An auxiliary passage formed therein will be described with reference to FIGS. 12 and 13.

In the fixing core 163, auxiliary passages 163B such as four grooves are formed on the outer circumferential surface 163A facing the fixing sleeve 161. Each secondary passage 163B is formed in the lower surface 163D from the upper surface 163C of the fixing core 163. The secondary passage 163B allows the trapped air present in the gap G6 and the lower surface 163D side of the fixing core 163 to quickly pass to the upper surface 163C of the fixing core 163.

Here, the auxiliary passages 163B are formed to have U-shaped cross-sections at four locations, but these may be formed at any number of locations, and may be other suitable shapes.

In addition, the lower surface 162B of the backflow tube 162 facing the fixed core 163 is grooved as the auxiliary passage 162C. The secondary passage 162C extends into the hole at the center of the backflow tube 162. Therefore, the secondary passage 162C is fixed core 163 through the trapped air, and / or secondary passage 163B, present in a slight gap in the fixed sleeve 161, the backflow tube 162 and the fixed core 163. The trapped air passed between the upper surface 163B and the fixed sleeve 161 of the gas is quickly passed through the outlet passage 167B (see FIG. 11) and replaced with fuel. A secondary passage similar to the secondary passage 162C may be formed on the end of the fixing core 163 facing the backflow tube 162 for the same purpose.

If the secondary passage 162C and the secondary passage 163B are formed at a place where they are in communication with each other, the entrapped air present in the gap G6 and the lower surface 163D side of the fixed core 163 is fixed to the fixed core ( The trapped air sent to the upper surface 163C of the 163 and the trapped air sent to the upper surface 163C can be sent to the gap G5 through the auxiliary passage 162C, so that the trapped air is discharged Through the furnace 145B can be quickly discharged from the gap (G5).

In the present embodiment, the auxiliary passages 162C are formed at four positions, but this is not limited, and these can be formed at one or more positions, while the shape and the like can also be appropriately determined. The secondary passage 162C may also be machined to the surface of the fixed core 163 in contact with the backflow tube 162.

As is apparent from the above, the fuel injector 101 has a bush 167 in which the outflow path 167B is formed, so that pressurized fuel sent from the magnet unit 106 to trap air trapped in the gap between components in the fixed sleeve 161. By outflowing to the outside of the fixed sleeve 161 and being replaced with fuel, for example, if the fuel injector 101 is installed in a cylinder to perform fuel injection operation, the trapped air is quickly replaced with fuel after the start of operation. can do.

This fills the gap completely with fuel in a short time, so a sufficient valve closing force can be obtained. Thereby, the amount of fluctuation in the suction / repulsion action of the armature operated in response to the on-off of the current supply to the magnetic valve used to control the communication state between the control chamber and the low pressure part is the air remaining in the gap. Since it is not changed because of insufficient valve closing force, the injected fuel amount can be stably controlled even immediately after installation of the fuel injector, and the fluctuation of the internal combustion engine speed can be suppressed. Therefore, the efficiency is very high because unnecessary running time or fuel consumption does not occur.

As is apparent from the above, the fuel injector according to the present invention ensures operational stability immediately after installation.

Claims (11)

Injector body has a fuel injection having a hollow cylindrical fixed core fixed in a fixed sleeve and a magnet unit configured as a bush fixed in a central hollow of the fixed core. A magnetic valve for control is provided, and the magnetic unit is provided between a control chamber and a low pressure section for accumulating high-pressure fuel for controlling the raising operation of the nozzle needle. In a fuel injector, in which the high pressure fuel in the control chamber flows out to the low pressure part through the bush when is opened, A fuel injector, wherein a fluid seal is provided between the components contained in the fixed sleeve to prevent fuel from penetrating into the gaps between the components and outflow from the high pressure portion in the control chamber to the low pressure portion. The fuel injector of claim 1, wherein the sealing member is configured in an annular gap formed between the fixed sleeve and the fixed core, and the other sealing member is configured in an annular gap formed between the fixed core and the bush. The fuel injector of claim 1, wherein the oiltight seal is formed against an annular gap formed between the fixed sleeve and the fixed core by forcibly contacting the outer edge of the fixed core with the fixed sleeve along an inner circumferential surface of the fixed sleeve. . The fixing coil according to any one of claims 1 to 3, wherein the exciting coil fixed in the fixing core is molded in a resilient coating material, and the coating material elastically presses the fixing core. Fuel injector to form a hermetic seal between the coils. 4. The exciting coil of claim 1, wherein the exciting coil fixed in the fixed core is formed in a resilient covering material, wherein a portion of the covering material elastically presses the fixing core to between the fixing core and the exciting coil. Fuel injector to form a hermetic seal on. The fuel injector of claim 1, wherein the stationary core is molded into a resilient coating material, the coating material forming a required hermetic seal. A fuel injector having an injector body equipped with a magnetic valve for fuel injection control having a magnet unit configured as a plurality of components assembled in a fixed sleeve, And an outlet passage for allowing air trapped in a gap of a component in the fixed sleeve by fuel sent to the magnet unit to flow out of the fixed sleeve and replaced with fuel. The injector body is provided with a magnetic valve for fuel injection control having a hollow cylindrical fixed core fixed in a fixed sleeve and a magnet unit configured as a bush fixed in a central hollow portion of the fixed core, wherein the magnetic unit is configured to raise the nozzle needle. In the fuel injector is installed between the control chamber and the low pressure section for accumulating the high pressure fuel for controlling the operation, the high pressure fuel in the control chamber flows out to the low pressure section through the bush when the magnetic valve is opened, A fuel injector characterized in that an outlet passage is formed in the bush for allowing air trapped in the gap of the components in the fixed sleeve by the fuel sent to the magnet unit to flow out of the fixed sleeve and replaced with fuel. 9. The fuel injector of claim 8, wherein an outlet passage is formed to allow air in the gap generated between the component installed between the fixed sleeve and the bush to flow into the bush. 10. The fuel injector according to claim 8 or 9, wherein an auxiliary passage is formed on the peripheral surface of the fixed core to allow the trapped air to flow out of the fixed sleeve. 10. The fuel injector according to claim 8 or 9, wherein an auxiliary passage is provided on an end surface of the fixed core to allow the trapped air to flow out of the fixed sleeve.