JP2001527186A - Fuel injection valve for internal combustion engine - Google Patents

Abstract

(57) [Summary] A fuel injection valve for an internal combustion engine is described here. A needle valve (2) movable axially in a nozzle member (6) forming an injection nozzle together with a valve seat (4) in a closing direction by a valve closing mechanism (8, 10, 12, 13, 14, 15). Receive a load. The needle valve (2) is surrounded by an injection space (24) into which the fuel to be injected at high pressure is introduced. In this case, when a predetermined opening pressure is exceeded, the needle valve (2) is lifted from the valve seat (4) against the force of the valve closing mechanism (8, 10, 12, 13, 14, 15), and the injection nozzle is opened. . According to the present invention, in order to start the internal combustion engine by lowering the opening pressure, an adjusting device (17, 18) for reducing the force of the valve closing mechanism (8, 10, 12, 13, 14, 15) is provided. . The time interval for reducing the force of the valve closing mechanism (8, 10, 12, 13, 14, 15) can be controlled by the control device (30).

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a fuel injection valve for an internal combustion engine according to the first aspect of the present invention.

[0002] In internal combustion engines, especially large diesel engines, fuel injection valves are used to inject fuel into the combustion chamber of the internal combustion engine. The internal combustion engine includes a needle valve movably supported in a nozzle member in an axial direction, a valve seat acting on the needle valve, a valve closing mechanism for closing the needle valve, and an injection valve surrounding the needle valve. There is space. The fuel to be injected at high pressure is introduced into this injection space surrounding the needle valve via a high-pressure channel. In this case, when the pressure exceeds the predetermined opening pressure in the injection space, the needle valve moves against the force of the valve closing mechanism, and fuel is injected into the combustion chamber of the internal combustion engine.

[0003] In order to shorten the injection time, the opening pressure has tended to increase further, and at present opening pressures of 900 bar or more are already being used. However, the consequence of this is that when starting the internal combustion engine, the high pressure required to open the nozzle cannot be achieved, so that the internal combustion engine usually does not start with known starting devices.

[0004] It is therefore an object of the present invention to provide a fuel injection valve for an internal combustion engine, which is designed for operation at a high opening pressure and does not cause starting difficulties.

[0005] This problem is solved by a fuel injection valve having the features of claim 1.

[0006] Other advantageous embodiments of the fuel injection valve according to the invention are disclosed in the dependent claims.

A fuel injection valve for injecting fuel into a combustion chamber of an internal combustion engine has one needle valve supported movably in an axial direction within a nozzle member, a valve seat acting on the needle valve, and the needle valve. There is a valve closing mechanism acting in the closing direction and an injection space surrounding the needle valve. Fuel to be injected at a high pressure is introduced into this injection space via a high-pressure passage. In this case, when the pressure becomes equal to or higher than the predetermined opening pressure of the injection space, the needle valve moves in the opening direction against the force of the valve closing mechanism, and injects fuel into the combustion chamber of the internal combustion engine. According to the present invention, the fuel injection valve includes an adjusting device that reduces the force of the valve closing mechanism during the start process of the internal combustion engine, and a control device that controls a time interval in which the force of the valve closing mechanism is reduced by the adjusting mechanism. There is.

Thus, the advantage of the fuel injector according to the invention is that during operation the fuel is injected at high pressure into the combustion chamber of the internal combustion engine, whereas the opening pressure during the starting process is reduced,
No additional or special starting device is required for the internal combustion engine.

According to one embodiment of the present invention, the valve closing mechanism has a spring device for closing the needle valve, and the prestress of the spring of the spring device can be changed by the adjusting device.

According to one embodiment of the present invention, the adjusting device has an adjusting piston arranged so as to move axially through a hole provided in the valve holder of the injection valve, and the adjusting piston applies a force applied to the needle valve. In order to adjust the valve closing mechanism.

In that case, an adjusting piston is connected to the spring device in order to vary the prestress of the spring.

According to one embodiment, two abutments are provided for determining the final position of the adjusting piston corresponding to two different pre-specified closing forces of the valve closing mechanism.

According to an advantageous embodiment, the abutment device has means for adjusting the final position of the adjusting piston.

According to an advantageous embodiment, the valve closing mechanism of the fuel injector has two valve closing springs which are mechanically connected in parallel between the needle valve and the regulating device.

According to an advantageous embodiment, two valve closing springs are arranged one after the other in a bore provided in the valve holder of the injection valve, and are mounted in this bore so as to be movable axially. One sliding sleeve is in the valve closing mechanism, the first spring is connected at one end to the needle valve via the first connecting rod and at the other end to the adjusting device via the sliding sleeve surrounding the second spring. The second spring has one end connected to the needle valve and the other end connected to the adjustment device via the second connection rod and the first connection rod passing through the first spring.

According to a particularly advantageous embodiment of the fuel injection valve according to the invention, the adjusting piston can be operated during operation by means of pressurized leaking fuel which occurs at the injection valve.

According to an advantageous embodiment of the invention, it is provided that the fuel injection valve forms a fuel mixing pressure passage leading from the needle valve to the side of the adjusting piste opposite the valve closing mechanism, so that the leaking fuel hitting the valve needle It communicates with the adjustment piston facing the valve closing mechanism and gradually moves it in a direction to increase the closing force of the valve closing mechanism.

According to a particularly advantageous configuration of the invention, a control device in the form of a control valve is provided which is connected to the side of the regulating piston to which the leaking fuel is applied, by means of which the control valve is perpendicular to the closing force of the valve closing mechanism. The load on the control valve can be reduced by the pressure of the leaked combustion generated by moving the control piston in any direction.

In this case, it is advantageous if the control valve is connected to a fuel mixing pressure passage leading from the needle valve to the regulating piston.

The control valve is advantageously formed as a needle valve having a needle tip and a valve seat for receiving the needle valve. In that case, the needle valve closes or opens a load release hole passing through the valve seat to reduce the burden of leaking fuel applied to the adjustment piston.

Advantageously, the control valve has a valve spring acting on the needle valve in the closing direction.

According to an advantageous embodiment of the invention, there is a control piston on the control valve, which is connected to the needle valve, the control piston acting in the direction of opening of the needle valve by means of a gaseous or liquid medium.

According to an advantageous embodiment of the invention, the control piston is formed integrally with the needle valve, the gaseous or liquid medium being applied on the side facing the tip of the needle, the tip of the needle being On the opposite side, the needle valve is supported against a valve spring that acts on the needle valve in the closing direction.

The medium applied to the control piston is the compressed air used to start the internal combustion engine.

According to an advantageous embodiment, the control valve is configured as a safety valve that opens automatically when the fuel pressure exceeds a predetermined fuel pressure and reduces the load on the adjusting piston.

In particular, the control valve is designed as a safety valve, and is designed such that when the strength of the valve spring exceeds a predetermined fuel pressure, the control valve opens automatically and reduces the load on the adjusting piston.

According to an advantageous embodiment of the invention, the adjusting piston is connected to a passage communicating with the fuel pressure on the side facing the valve closing mechanism which applies the mixed pressure of the opening pressure and the injection pipe residual pressure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a longitudinal section of a fuel injection valve according to an embodiment of the present invention. Reference numeral 1 denotes a valve holder in which all the main parts of the fuel injector are mounted and held. Reference numeral 6 denotes a nozzle member, which includes the components of the actual injection nozzle. A needle valve 2 is mounted on the nozzle member 6 so as to be movable in the axial direction. The needle valve acts on the valve seat 4 in a direction to open and close an injection nozzle formed thereby. A valve closing mechanism is mounted on the nozzle holder 1, and includes a first connecting rod 8, a second connecting rod 10, a first valve closing spring 12, a second valve closing spring 14, a sliding sleeve 14, and a sliding sleeve. It is formed by a guide sleeve 15 arranged on the moving sleeve 14. The first connecting rod 8 is axially movably supported in the first hole 9 of the valve holder 1 and is connected to the needle valve 2. The second connecting rod 10 is axially displaceably mounted in the guide sleeve 15 of the sliding sleeve 14 and is connected to the first connecting rod 8, which slide sleeve 14 is provided in the second bore 11 of the valve holder 1. It is mounted movably in the axial direction. The first valve closing spring 12 acts between the first connecting rod 8 and the sliding sleeve 14, while the second valve closing spring 13 operates between the second connecting rod 10 and the sliding part 16.
Work between. This sliding portion 16 is also used in the second hole 11 of the valve holder 1 so as to be movable in the axial direction. The sliding part 16 also acts on the sliding sleeve 14.

There is an injection space 24 around the needle valve 2. The fuel pressurized through the high-pressure passage 25 is introduced into the injection space for injection into the combustion chamber of the internal combustion engine. When the pressure exceeds a predetermined pressure determined by the predetermined stresses of the two valve closing springs 12, 13, the needle valve 2 lifts up from the valve seat 4, and fuel flows from the injection space 24 through the nozzle opening 5 to the combustion chamber of the internal combustion engine. It is injected. Leaked fuel leaking between the needle valve 2 and the nozzle member 6 during operation is collected in the fuel collecting hole 29 and discharged through the fuel mixing pressure passage 26.

On the back side of the sliding part 6, there is provided an adjusting device for varying the force of the valve closing mechanism formed by the members 8, 10, 12, 13, 14, 15 for starting the internal combustion engine. Fuel with low fuel pressure can be injected. This regulating valve is formed by a regulating piston 17 in the embodiment of the fuel injection valve shown in FIG. This piston is arranged in a third hole 18 formed in the valve holder 1 so as to be movable in the axial direction of the valve holder 1. In this periphery, the adjusting piston 17 is provided with a sealing ring 19, which seals its periphery against the third bore 18. The adjusting piston 17 is located in the third hole 1
8 and is movable between two final positions determined by the abutment device. That is, first, the contact side 18a of the adjustment piston 17 on the side facing the valve closing mechanism and the stopper 21 on the opposite side, and the contact adjustment 18 is screwed into the screw inside the adjustment piston 17. The screw 20 hits. The stopper 21 is screwed into the sealing plug 22 and can be adjusted by a contact adjusting screw 23. This airtight stopper 22 closes the rear end of the valve holder 1. On the side opposite to the sliding portion 16, the adjusting piston 17 is provided with a contact bolt 2.
0a is provided. This bolt can also be adjusted with an adjusting screw and determines the dimension between the sliding part 16 and the adjusting piston 17.

The space behind the adjusting piston 17, that is, the space on the side facing the sliding portion 16 or the valve closing mechanism, is connected to a fuel mixing pressure passage 26 via a connecting passage 27.
Further, a control valve is connected to the fuel mixing pressure passage 26. This control valve is generally designated by the reference numeral 30 in FIG. 1a) and is shown enlarged in FIG. 1b).
The movement of the adjustment piston 17 brings the valve closing mechanism into two states. That is, in the first state with the adjusting piston 17 in its final position on the rear side, the sliding part 16 and the sliding sleeve 14 move to the left in the drawing, so that both closing springs 12 and 13 are relaxed to a certain extent. In this state, if the pressure of the fuel in the injection space is low, the needle valve 2 opens, so that the internal combustion engine can be started. In the second state, since the adjusting piston 17 is in contact with the contact end 18a, the sliding portion 16 and the sliding sleeve 14 move to the right.
This urges both closing springs 12 and 13 more strongly, so that the needle valve 2
Opens when the pressure in the injection space 24 increases. In this situation, the fuel is injected at a high pressure and therefore in a very short time into the combustion chamber of the internal combustion engine. The fuel pressure corresponding to both end positions of the adjusting piston 17 is, for example, 300 or 900 bar.

The adjustment of the adjustment piston 17 is performed as follows. When the internal combustion engine is stopped, the adjusting piston 17 is in the final left position. In this position, the adjusting piston is brought into its position by the force of both valve closing springs 12 and 13. After the internal combustion engine is started, the adjusting piston 17 is gradually brought into contact with the abutting end until the final position is reached by the leaking fuel flowing from the fuel collecting hole 29 to the back side of the adjusting piston 17 via the fuel mixing pressure passage 26 and the connection passage 27. Move in the direction of 18a. The speed at which the piston 17 moves, that is, the time interval of the movement, is determined by the amount of leaking fuel introduced through the fuel mixing pressure passage 26 and the connection passage 27.

After the internal combustion engine has been shut down, the adjusting piston 17 first remains in its final position at the abutment end 18a corresponding to the high opening pressure due to the high pressure leaking fuel located behind. A control valve 30 is provided to constantly reduce the load on the back side of the adjusting piston 17 if necessary, to move the adjusting piston and to reduce the required opening pressure.

FIG. 1 b) shows the control valve 30 in an enlarged manner, and will be described in detail here.
The control valve 30 includes a needle valve 34 having a needle tip 35. The needle tip 35 is housed by a valve seat 36 having a hole passing through the fuel mixing pressure passage 26 penetrating therethrough. The front part of the needle valve 34 is surrounded by a hollow space 39 connected to the discharge hole 50. The needle valve 34 is sealed against a hole 37 by a sealing ring 38, in which the needle valve 34 is disposed so as to be movable in the axial direction.

The control piston 31 is formed by being incorporated into a needle valve 34. The control piston is movably mounted in a bore 32 and the control piston 3
1 is sealed by a sealing ring 33. A hollow space 60 is provided in front of the control piston 31. Behind the control piston 31 is a valve spring 41, which is shown in broken lines in the drawing. This valve spring has one end supported by the control piston 31 and the other end supported by the stopper 42. The stopper is located at a screw bolt 43, which is screwed into the rear end of the valve holder 1 and seals the hole for the control valve 30. The contact rod 40 passing through the screw plug 43 can be adjusted by an adjusting nut 44. Between the abutment rod 40 and the projection 45 on the rear side of the control piston 31, it is possible to adjust the play H by which the control piston 31 can be moved between both end positions.

A liquid or gaseous medium is introduced into the hollow space 60 via a hole or a passage (not shown). This medium allows the control piston 31 to move to the rear end position against the force of the valve spring 41, so that the needle point 35 of the needle valve 34 is
6 to open a hole through the valve seat 36. Thus, the adjusting piston 17
Can be opened through the connection passage 27 and the fuel mixing pressure passage 26, and the leaked fuel is discharged through the hole through the valve seat 36 of the control valve 30 and the hollow hole 39 through the hollow space 39.
0, from which it is mixed, for example, with the remaining leaking fuel of the injector.

To apply the air to the hollow space 60 on the front side of the control piston 31, start air is suitable for starting the engine with air. This means that when pressurized into the hollow space 60 during the starting process, the control piston 31 immediately reaches the rear end position, the control valve 30 opens, and the load on the back side of the adjusting piston 17 is reduced. The piston is in the rear, final position, reducing the load on the valve closing mechanism. Alternatively, the hollow space 60 may be loaded by an external liquid or an external gaseous medium.

Another function of the control valve 30 is that of a safety valve. For this reason, when the strength of the valve spring 41 exceeds the critical pressure on the back side of the adjusting piston 17 which propagates to the needle tip 35 of the needle valve 34 via the connection passage 27 and the fuel mixing pressure passage 26, the needle tip 35 It is designed in such a way that it lifts out of the seat 36, whereby the load on the space behind the adjusting piston 17 is reduced. This safety feature of the control valve 30 ensures that the fuel injector mechanism is protected against possible overloads due to overpressure.

[0039]

[Brief description of the drawings]

FIG. 1 a) a longitudinal sectional view of an embodiment of a fuel injection valve according to the invention, and b)
FIG. 3 is an enlarged partial view of a) showing a control valve of a fuel injection valve according to an embodiment of the present invention in detail.

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] November 17, 1999 (November 17, 1999)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

19. The fuel injection valve according to claim 1, wherein an externally introduced hydraulic or pneumatic pressure is applied to the adjusting piston (17).

[Procedure amendment]

[Submission date] July 24, 2000 (2000.7.24)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Title of the Invention] Fuel injection valve for internal combustion engine

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a fuel injection valve for an internal combustion engine according to the first aspect of the present invention.

[0002] In internal combustion engines, especially large diesel engines, fuel injection valves are used to inject fuel into the combustion chamber of the internal combustion engine. The internal combustion engine includes a needle valve movably supported in a nozzle member in an axial direction, a valve seat acting on the needle valve, a valve closing mechanism for closing the needle valve, and an injection valve surrounding the needle valve. There is space. The fuel to be injected at high pressure is introduced into this injection space surrounding the needle valve via a high-pressure channel. In that case, when the pressure becomes equal to or higher than the predetermined opening pressure in the injection space, the needle valve moves in the opening direction against the force of the valve closing mechanism,
Fuel is injected into the combustion chamber of the internal combustion engine.

[0003] In order to shorten the injection time, the opening pressure has tended to increase further, and at present opening pressures of 900 bar or more are already being used. However, the consequence of this is that when starting the internal combustion engine, the high pressure required to open the nozzle cannot be achieved, so that the internal combustion engine usually does not start with known starting devices.

[0004] It is therefore an object of the present invention to provide a fuel injection valve for an internal combustion engine, which is designed for operation at a high opening pressure and does not cause starting difficulties.

[0005] This problem is solved by a fuel injection valve having the features of claim 1.

[0006] Other advantageous embodiments of the fuel injection valve according to the invention are disclosed in the dependent claims.

A fuel injection valve for injecting fuel into a combustion chamber of an internal combustion engine has one needle valve supported movably in an axial direction within a nozzle member, a valve seat acting on the needle valve, and the needle valve. There is a valve closing mechanism acting in the closing direction and an injection space surrounding the needle valve. Fuel to be injected at a high pressure is introduced into this injection space via a high-pressure passage. In this case, when the pressure becomes equal to or higher than the predetermined opening pressure of the injection space, the needle valve moves in the opening direction against the force of the valve closing mechanism, and injects fuel into the combustion chamber of the internal combustion engine. According to the present invention, the fuel injection valve includes an adjusting device that reduces the force of the valve closing mechanism during the start process of the internal combustion engine, and a control device that controls a time interval in which the force of the valve closing mechanism is reduced by the adjusting mechanism. There is.

Thus, the advantage of the fuel injector according to the invention is that during operation fuel is injected into the combustion chamber of the internal combustion engine at a high opening pressure, whereas the opening pressure decreases during the starting process, so that the internal combustion engine No additional or special starting device is required.

According to one embodiment of the present invention, the valve closing mechanism has a spring device for closing the needle valve, and the prestress of the spring of the spring device can be changed by the adjusting device.

According to one embodiment of the present invention, the adjusting device has an adjusting piston arranged so as to move axially through a hole provided in the valve holder of the injection valve, and the adjusting piston applies a force applied to the needle valve. In order to adjust the valve closing mechanism.

In that case, an adjusting piston is connected to the spring device in order to vary the prestress of the spring.

According to one embodiment, two abutments are provided for determining the final position of the adjusting piston corresponding to two different pre-specified closing forces of the valve closing mechanism.

According to an advantageous embodiment, the abutment device has means for adjusting the final position of the adjusting piston.

According to an advantageous embodiment, the valve closing mechanism of the fuel injector has two valve closing springs which are mechanically connected in parallel between the needle valve and the regulating device.

According to an advantageous embodiment, two valve closing springs are arranged one after the other in a bore provided in the valve holder of the injection valve, and are mounted in this bore so as to be movable axially. One sliding sleeve is in the valve closing mechanism, the first spring is connected at one end to the needle valve via the first connecting rod and at the other end to the adjusting device via the sliding sleeve surrounding the second spring. The second spring has one end connected to the needle valve and the other end connected to the adjustment device via the second connection rod and the first connection rod passing through the first spring.

According to a particularly advantageous embodiment of the fuel injection valve according to the invention, the adjusting piston can be operated during operation by means of pressurized leaking fuel which occurs at the injection valve.

According to an advantageous embodiment of the invention, it is provided that the fuel injection valve forms a fuel mixing pressure passage leading from the needle valve to the side of the adjusting piste opposite the valve closing mechanism, so that the leaking fuel hitting the valve needle It communicates with the adjustment piston facing the valve closing mechanism and gradually moves it in a direction to increase the closing force of the valve closing mechanism.

According to a particularly advantageous configuration of the invention, a control device in the form of a control valve is provided which is connected to the side of the regulating piston to which the leaking fuel is applied, by means of which the control valve is perpendicular to the closing force of the valve closing mechanism. The load on the control valve can be reduced by the pressure of the leaked combustion generated by moving the control piston in any direction.

In this case, it is advantageous if the control valve is connected to a fuel mixing pressure passage leading from the needle valve to the regulating piston.

The control valve is advantageously formed as a needle valve having a needle tip and a valve seat for receiving the needle valve. In that case, the needle valve closes or opens a load release hole passing through the valve seat to reduce the burden of leaking fuel applied to the adjustment piston.

Advantageously, the control valve has a valve spring acting on the needle valve in the closing direction.

According to an advantageous embodiment of the invention, there is a control piston on the control valve, which is connected to the needle valve, the control piston acting in the direction of opening of the needle valve by means of a gaseous or liquid medium.

According to an advantageous embodiment of the invention, the control piston is formed integrally with the needle valve, the gaseous or liquid medium being applied on the side facing the tip of the needle, the tip of the needle being On the opposite side, the needle valve is supported against a valve spring that acts on the needle valve in the closing direction.

The medium applied to the control piston is the compressed air used to start the internal combustion engine.

According to an advantageous embodiment, the control valve is configured as a safety valve that opens automatically when the fuel pressure exceeds a predetermined fuel pressure and reduces the load on the adjusting piston.

In particular, the control valve is designed as a safety valve, and is designed such that when the strength of the valve spring exceeds a predetermined fuel pressure, the control valve opens automatically and reduces the load on the adjusting piston.

According to an advantageous embodiment of the invention, the adjusting piston is connected to a passage communicating with the fuel pressure on the side facing the valve closing mechanism which applies the mixed pressure of the opening pressure and the injection pipe residual pressure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a longitudinal section of a fuel injection valve according to an embodiment of the present invention. Reference numeral 1 denotes a valve holder in which all the main parts of the fuel injector are mounted and held. Reference numeral 6 denotes a nozzle member, which includes the components of the actual injection nozzle. A needle valve 2 is mounted on the nozzle member 6 so as to be movable in the axial direction. The needle valve acts on the valve seat 4 in a direction to open and close an injection nozzle formed thereby. A valve closing mechanism is attached to the nozzle holder 1, and includes a first connecting rod 8, a second connecting rod 10, a first valve closing spring 12, a second valve closing spring 13, a sliding sleeve 14, and a sliding sleeve. It is formed by a guide sleeve 15 arranged on the moving sleeve 14. The first connecting rod 8 is axially movably supported in the first hole 9 of the valve holder 1 and is connected to the needle valve 2. The second connecting rod 10 is axially displaceably mounted in the guide sleeve 15 of the sliding sleeve 14 and is connected to the first connecting rod 8, which slide sleeve 14 is provided in the second bore 11 of the valve holder 1. It is mounted movably in the axial direction. The first valve closing spring 12 acts between the first connecting rod 8 and the sliding sleeve 14, while the second valve closing spring 13 operates between the second connecting rod 10 and the sliding part 16.
Work between. This sliding part 16 is also supported in the second hole 11 of the valve holder 1 so as to be movable in the axial direction. The sliding part 16 also acts on the sliding sleeve 14.

There is an injection space 24 around the needle valve 2. The fuel pressurized through the high-pressure passage 25 is introduced into the injection space for injection into the combustion chamber of the internal combustion engine. When the pressure exceeds a predetermined pressure determined by the predetermined stresses of the two valve closing springs 12, 13, the needle valve 2 lifts up from the valve seat 4, and fuel flows from the injection space 24 through the nozzle opening 5 to the combustion chamber of the internal combustion engine. It is injected. Leaked fuel leaking between the needle valve 2 and the nozzle member 6 during operation is collected in the fuel collecting hole 29 and discharged through the fuel mixing pressure passage 26.

On the rear side of the sliding part 16 there is provided an adjusting device for varying the force of the valve closing mechanism formed by the members 8, 10, 12, 13, 14, 15 for starting the internal combustion engine. Fuel with low fuel pressure can be injected. This regulating valve is formed by a regulating piston 17 in the embodiment of the fuel injection valve shown in FIG. This piston is arranged in a third hole 18 formed in the valve holder 1 so as to be movable in the axial direction of the valve holder 1. In this periphery, the adjusting piston 17 is provided with a sealing ring 19, which seals its periphery against the third bore 18. The adjusting piston 17 is movable between two final positions in the third bore 18 as determined by the abutment device. That is, first, the contact side 18a of the adjustment piston 17 on the side facing the valve closing mechanism and the stopper 21 on the opposite side, and the contact adjustment 18 is screwed into the screw inside the adjustment piston 17. The screw 20 hits. The stopper 21 is screwed into the sealing plug 22 and can be adjusted by a contact adjusting screw 23. This airtight stopper 22 closes the rear end of the valve holder 1. On the side facing the sliding part 16, the adjusting piston 17 is provided with a contact bolt 20a. This bolt can also be adjusted with an adjusting screw and determines the dimension between the sliding part 16 and the adjusting piston 17.

The space behind the adjusting piston 17, that is, the space on the side facing the sliding portion 16 or the valve closing mechanism, is connected to a fuel mixing pressure passage 26 via a connecting passage 27.
Further, a control valve is connected to the fuel mixing pressure passage 26. This control valve is generally designated by the reference numeral 30 in FIG. 1a) and is shown enlarged in FIG. 1b).
The movement of the adjustment piston 17 brings the valve closing mechanism into two states. That is, in the first state with the adjusting piston 17 in its final position on the rear side, the sliding part 16 and the sliding sleeve 14 move to the left in the drawing, so that both closing springs 12 and 13 are relaxed to a certain extent. In this state, if the pressure of the fuel in the injection space is low, the needle valve 2 opens, so that the internal combustion engine can be started. In the second state, since the adjusting piston 17 is in contact with the contact end 18a, the sliding portion 16 and the sliding sleeve 14 move to the right.
This urges both closing springs 12 and 13 more strongly, so that the needle valve 2
Opens when the pressure in the injection space 24 increases. In this situation, the fuel is injected at a high pressure and therefore in a very short time into the combustion chamber of the internal combustion engine. The fuel pressure corresponding to both end positions of the adjusting piston 17 is, for example, 300 or 900 bar.

The adjustment of the adjustment piston 17 is performed as follows. When the internal combustion engine is stopped, the adjusting piston 17 is in the final left position. In this position, the adjusting piston is brought into its position by the force of both valve closing springs 12 and 13. After the internal combustion engine is started, the adjusting piston 17 is gradually brought into contact with the abutting end until the final position is reached by the leaking fuel flowing from the fuel collecting hole 29 to the back side of the adjusting piston 17 via the fuel mixing pressure passage 26 and the connection passage 27. Move in the direction of 18a. The speed at which the piston 17 moves, that is, the time interval of the movement, is determined by the amount of leaking fuel introduced through the fuel mixing pressure passage 26 and the connection passage 27.

After the internal combustion engine has been shut down, the adjusting piston 17 first remains in its final position at the abutment end 18a corresponding to the high opening pressure due to the high pressure leaking fuel located behind. A control valve 30 is provided to constantly reduce the load on the back side of the adjusting piston 17 if necessary, to move the adjusting piston and to reduce the required opening pressure.

FIG. 1 b) shows the control valve 30 in an enlarged manner, and will be described in detail here.
The control valve 30 includes a needle valve 34 having a needle tip 35. The needle tip 35 is housed by a valve seat 36 having a hole passing through the fuel mixing pressure passage 26 penetrating therethrough. The front part of the needle valve 34 is surrounded by a hollow space 39 connected to the discharge hole 50. The needle valve 34 is sealed against a hole 37 by a sealing ring 38, in which the needle valve 34 is disposed so as to be movable in the axial direction.

The control piston 31 is formed by being incorporated into a needle valve 34. The control piston is movably mounted in a bore 32 and the control piston 3
1 is sealed by a sealing ring 33. A hollow space 60 is provided in front of the control piston 31. Behind the control piston 31 is a valve spring 41, which is shown in broken lines in the drawing. This valve spring has one end supported by the control piston 31 and the other end supported by the stopper 42. The stopper is located at a screw bolt 43, which is screwed into the rear end of the valve holder 1 and seals the hole for the control valve 30. The contact rod 40 passing through the screw plug 43 can be adjusted by an adjusting nut 44. Between the abutment rod 40 and the projection 45 on the rear side of the control piston 31, it is possible to adjust the play H by which the control piston 31 can be moved between both end positions.

A liquid or gaseous medium is introduced into the hollow space 60 via a hole or a passage (not shown). This medium allows the control piston 31 to move to the rear end position against the force of the valve spring 41, so that the needle point 35 of the needle valve 34 is
6 to open a hole through the valve seat 36. Thus, the adjusting piston 17
Can be opened through the connection passage 27 and the fuel mixing pressure passage 26, and the leaked fuel is discharged through the hole through the valve seat 36 of the control valve 30 and the hollow hole 39 through the hollow space 39.
0, from which it is mixed, for example, with the remaining leaking fuel of the injector.

To apply the air to the hollow space 60 on the front side of the control piston 31, start air is suitable for starting the engine with air. This means that when pressurized into the hollow space 60 during the starting process, the control piston 31 immediately reaches the rear end position, the control valve 30 opens, and the load on the back side of the adjusting piston 17 is reduced. The piston is in the rear, final position, reducing the load on the valve closing mechanism. Alternatively, the hollow space 60 may be loaded by an external liquid or an external gaseous medium.

Another function of the control valve 30 is that of a safety valve. For this reason, when the strength of the valve spring 41 exceeds the critical pressure on the back side of the adjusting piston 17 which propagates to the needle tip 35 of the needle valve 34 via the connection passage 27 and the fuel mixing pressure passage 26, the needle tip 35 It is designed in such a way that it lifts out of the seat 36, whereby the load on the space behind the adjusting piston 17 is reduced. This safety feature of the control valve 30 ensures that the fuel injector mechanism is protected against possible overloads due to overpressure.

[0039]

[Brief description of the drawings]

FIG. 1 a) a longitudinal sectional view of an embodiment of a fuel injection valve according to the invention, and b)
FIG. 3 is an enlarged partial view of a) showing a control valve of a fuel injection valve according to an embodiment of the present invention in detail.

──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G066 AA07 AB02 BA07 BA19 CC06T CC14 CC52 CC53 CC64T CC68T CE12 CE15

Claims (21)

[Claims] 1. A needle valve (2) supported in a nozzle member (6) movably in an axial direction, a valve seat (4) acting on the needle valve (2), and a needle valve (2). A valve closing mechanism (8, 10, 12, 13, 14, 15) for setting a valve in a closing direction;
An injection space (24) surrounding the needle valve (2) and into which high-pressure fuel to be injected via the high-pressure passage (25) is introduced, wherein when the injection space (24) exceeds a predetermined pressure, the needle valve (2) The valve closing mechanism (8, 10, 12, 13, 14, 1)
The fuel injection valve moves in the opening direction against the force of 5), the fuel is injected into the combustion chamber of the internal combustion engine (opening pressure), and the fuel is injected into the combustion chamber of the internal combustion engine. An adjusting device (17, 18) for reducing the force of the valve closing mechanism (8, 10, 12, 13, 14, 15), and a valve closing mechanism (8) by the adjusting mechanism (17, 18).
, 10, 12, 13, 14, 15, 15) for controlling a time interval for reducing the force of the fuel injection valve. 2. The valve closing mechanism (8, 10, 12, 13, 14, 15) has a spring device (12, 13) for closing the needle valve (2), and the initial stress of the spring is adjusted. 2. The fuel injection valve according to claim 1, wherein the fuel injection valve can be changed by a device (17, 18). 3. The adjusting device (17, 18) has an adjusting piston (17) which is axially displaceable in a bore (18) provided in the valve holder (1) of the injection valve. 3. The fuel injection valve according to claim 1, wherein the adjusting piston is connected to a valve closing mechanism for adjusting the force applied to the needle valve. 4. The fuel injection valve according to claim 1, wherein the adjusting piston is connected to a spring device for varying the spring initial stress. 5. Two abutment devices (21, 23 and 20, 20a) are provided, and these abutment devices provide a valve closing mechanism (8, 10, 12, 13, 14, 14, 15).
5. The fuel injection valve according to claim 3, wherein a final position of the adjusting piston corresponding to two different predetermined closing forces is determined. 6. The fuel injection valve according to claim 5, wherein the abutment device has means for adjusting the final position of the adjustment piston (17) (abutment adjustment screws 20 and 23). 7. A valve closing mechanism (8, 10, 12, 13, 14, 15) comprising two valves mechanically connected in parallel between the needle valve (2) and the adjusting device (17, 18). 7. The fuel injection valve according to claim 1, comprising a closing spring (12, 13). 8. A valve closing mechanism (8, 10, 12, 13, 14, 15) comprising two valve closing members arranged one after another in a hole (11) provided in a valve holder (1) of an injection valve. A first spring (12) having a spring (12, 13) and a sliding sleeve (14) axially movably mounted in the bore (11), wherein the first spring (12) is a first connecting rod (8). One end to the needle valve (2) via a sliding sleeve (14) surrounding the second spring and the other end to the adjusting device (17, 18) via a second spring (13). Spring (1
2) that one end is connected to the needle valve (2) and the other end is connected to the adjusting device (17, 18) via the second connecting rod (10) and the first connecting rod (8) penetrating therethrough. The fuel injection valve according to any one of claims 1 to 7, characterized in that: 9. The fuel injection valve according to claim 3, wherein the adjusting piston is operated by pressurized leaking fuel which is generated during operation in the injection valve. 10. A fuel injection valve is provided with a control piston (17) from a needle valve (2).
) Is formed with a fuel mixing pressure passage (26, 27) communicating with a side facing the valve closing mechanism (8, 10, 12, 13, 14, 15). The leaking fuel generated is controlled by a valve closing mechanism (8, 10, 12)
, 13, 14, 15), and passes this through the valve closing mechanism (8, 10, 12).
10. The fuel injection valve according to claim 9, wherein the fuel injection valve is gradually moved in a direction to increase the force of the fuel injection valve. 11. A control device (30) in the form of a control valve (30) connected to the side of the adjusting piston (17) to which the leaking fuel is applied, by means of which the adjusting piston is closed by a valve closing mechanism (8, 10,. The fuel injection valve according to claim 9 or 10, wherein the load on the adjusting piston is reduced by the pressure of the leaking oil generated for moving the closing force of (12, 13, 14, 15). 12. A control valve (30) is provided from a needle valve (2) to an adjustment piston (1).
12. The fuel injection valve according to claim 11, which is connected to a fuel mixing pressure passage (26) leading to (7). 13. A control valve (30) comprising a needle valve (34) having a needle tip (35).
) And a valve seat (36) having a needle tip (35), the needle valve (34) being adapted to reduce the load of leaking fuel on the adjusting piston (17). 13. The fuel injection valve according to claim 11, wherein a load relief hole passing through the opening is selectively closed or opened. 14. The control valve comprises a valve spring (4) for closing the needle valve (34) in the closing direction.
14. The fuel injection valve according to claim 13, comprising: (1). 15. A control piston (3) coupled to a needle valve (34).
15. The fuel injection valve according to claim 13, wherein the control piston operates in the opening direction of the needle valve by using a gaseous or liquid medium. 16. The control piston (31) is formed integrally with a needle valve (34), and a gaseous or liquid medium is applied to a side facing the needle tip (35), and is opposite to the needle tip (35). 16. The fuel injection valve according to claim 15, characterized in that it is supported on the side against a valve spring (41) for closing the needle valve (34). 17. The method according to claim 15, wherein the medium added to the control piston is compressed air used to start the internal combustion engine.
A fuel injection valve according to claim 1. 18. The control valve according to claim 11, wherein the control valve is configured to open automatically when a predetermined leaking oil pressure is exceeded and to reduce the load on the adjusting piston. The fuel injection valve according to any one of claims 1 to 4. 19. The control valve (30) is formed as a safety valve and includes a valve spring (41).
The control valve automatically opens when the strength of the oil exceeds a predetermined leak oil pressure, and the adjusting piston (1)
18. The method according to claim 14, which is designed to reduce the load of 7).
The fuel injection valve according to any one of claims 1 to 4. 20. A valve closing mechanism (8, 10, 12, 12) for fully controlling the mixing pressure from the amount of blocked leaking fuel consisting of the tip pressure and the residual pressure of the injection conduit. 20. The fuel injection system according to claim 15, wherein the fuel injection passage is connected to a pressure-inwardly leaking fuel passage for reducing a load on a side facing the fuel injection passage. valve. 21. A fuel injection valve according to claim 3, wherein an externally introduced hydraulic or pneumatic pressure is applied to the adjusting piston (17).