KR100972523B1 - Fuel injection valve - Google Patents

Abstract

The fuel injection valve 10 for the internal combustion engine is sealed with an actuator 11 operatively connected to the valve needle 15 guided by the nozzle body 26 and a valve seat surface 28 formed on the nozzle body 26. And a valve closing body 27 which is non-positively connected with the valve needle 15, forming a. The valve needle 15 and / or the valve closing body 27 comprise at least one grinding surface 29, which grinding surface is formed around the valve needle 15 and / or the valve closing body 27. Between the at least one grinding surface 29 and the corresponding surface 31 formed in the nozzle body 26, the throttle gap 32 having a cross section smaller than the open cross section of the sealing sheet in the open state of the fuel injection valve 10. Is formed.

Fuel injection valve, actuator, nozzle body, valve needle, valve closing body.

Description

Fuel injection valve

The present invention relates to a fuel injection valve according to the preamble of the independent claim.

DE 196 42 653 C1 is already known for forming ignitable fuel / air mixtures. When the nozzle opening is opened by separating the valve member from the valve seat including the nozzle opening, fuel is injected by an injector in each combustion chamber limited by the piston, thereby forming a ignitable fuel / air mixture in the cylinder of the direct injection internal combustion engine. Can be. Under all operating conditions of the internal combustion engine, in order to enable consumption- and emission-optimized internal mixture formation at each operating point of the overall characteristic field, especially during stratified air supply operation, the opening stroke and injection time of the valve member can be set variably. have.

DE 38 08 635 C2 is known for injecting fuel directly into a cylinder of a mixer-compressed internal combustion engine. The fuel injection device includes a fuel injection valve disposed in the cylinder wall toward the cylinder head and spaced apart from the outlet, and the jet axis of the fuel injection valve is directed toward an area around the spark plug disposed in the cylinder head. The fuel injection valve includes a self acting valve needle having a threaded spiral groove for generating a vortex of the injection jet. The jet axis of the fuel injection valve is directed towards the ignition point located in the middle of the cylinder head.

Also known from US 5 941 207 is a device for injecting fuel into a combustion chamber of a mixer compression external ignition internal combustion engine, in which the fuel is conically injected into the combustion chamber at a certain initial angle. In this case, the injected fuel fills the combustion chamber conical, and the effect of wall wetting is suppressed. A relatively flat piston forms a spherical shape of the fuel cloud injected during the compression step. The spherical mixture cloud is slightly mixed with the supplied air and guided to the spark gap of the spark plug upon further compression.

A disadvantage of the method or apparatus for injecting fuel into the combustion chamber of a mixer compression external ignition internal combustion engine, known from the above publications, is that the injected fuel is mixed with the supplied air to form an ignitable fuel / air mixture and It has a complex combustion chamber structure that is required to deliver it near the spark gap of the spark plug for ignition. The combustion chamber structure is difficult to manufacture on the one hand and on the other hand combustion cannot be optimized with regard to the emission of nitrogen oxides and the consumption of fuel.

It is also a disadvantage in most cases that the spark plugs are injection molded by direct fuel injection valves. This results in the spark plug being exposed to strong thermal shock loads on the one hand and soot deposited on the spark plug electrodes on the other hand, which significantly shortens the life of the spark plugs.

A disadvantage of the fuel injection valves, in particular known in DE 198 27 219 A1, is that the fuel injected into the combustion chamber at different injection angles mostly impinges on the walls or pistons of the combustion chamber, where it cools and releases or emits soot. It is a disadvantage that it can be burned.

The fuel injection valve according to the invention with the features of the independent claims is characterized in that the mixture cloud injected into the combustion chamber of the internal combustion engine is achieved by throttle in front of the sealing sheet by the corresponding shaping of the valve closing body of the fuel injection valve, so that the mixture cloud is injected. It has the advantage that it can be influenced to reach the spark plug only at the end of the process.

In this case the valve needle or the valve closing body has a grinding surface, the grinding surface throttles the fuel flow very or slightly strongly along the radial recess of the grinding surface, so that the cloud of mixture leaving the fuel injection valve regulates the stroke of the valve needle. With a larger or smaller opening angle α.

Measures implemented in the dependent claims enable a further refinement of the fuel injection valve set out in the independent claims.

It is particularly preferable that the predetermined throttle action can be freely selected, since the number of grinding surfaces is arbitrarily determined.

It is preferable that the guide of the valve needle is always ensured by the fact that the projecting guide surface disposed between the grinding surfaces cooperates with the corresponding surface formed in the nozzle body. This allows the error function to be prevented by the offset of the valve needle.

It is also preferred that the throttle action can be adjusted by means of the concavely arranged grinding surface or through the projecting guide ring.

Embodiments of the invention are briefly shown in the drawings and described in more detail in the following description.

1 is a longitudinal sectional view of an embodiment of a fuel injection system comprising a mixture cloud generated in a combustion chamber by a fuel injection valve according to the invention,

2 is a partial cross-sectional view of an embodiment of a fuel injection valve according to the present invention,

3A and 3B are cross-sectional views of the injection side portion of the embodiment shown in FIG. 2 of a fuel injection valve according to the invention in two different stroke positions,

4 is a second embodiment of a fuel injection valve according to the present invention, which is the same view as in FIGS. 3A and 3B.

1 shows a schematic schematic drawing showing an embodiment of a fuel injection system 1 for a mixer compression external ignition internal combustion engine.

The fuel injection system 1 comprises a combustion chamber 2, which is bounded by a cylinder wall 3, a cylinder head 4 having a ridge inclined surface 5, and a piston 6. The spark plug 7 is arranged to project into the combustion chamber 2, for example, from the side. The fuel injection valve 10 according to the invention is arranged between the ridge inclined surfaces 5 such that fuel is injected into the combustion chamber 2, for example in the form of a conical mixture cloud 8, 9.

In order to eliminate the aforementioned disadvantages associated with the stoichiometry of the direct injection molding of the mixture cloud 8, 9 and the spark plug 7, the fuel injection valve 10 is according to the invention that the fuel flow formed therein differs. By throttling to size, it is possible to form the mixture clouds 8, 9 in the combustion chamber 2 at varying opening angles α, depending on the stroke position of the valve needle of the fuel injection valve 10.

As shown in FIGS. 3A, 3B and 4 and described in more detail in the following description, a valve needle or a valve closing body operatively connected with the valve needle is provided for at least one preferably multiple grinding for this purpose. Face or guide ring.

By means of the measures according to the invention, first, a mixture cloud 8 having a large and small opening angle α can be formed in the combustion chamber 2, while the fuel injection valve 10 is closed in a short time. A mixture cloud 9 with a large opening angle α is formed, which passes through the spark plug 7 in the region of the electrode and thus carries the ignitable mixture to the spark gap of the spark plug 7.

An embodiment of a fuel injection valve 10 designed according to the invention suitable for this mode of operation is shown in FIG. 2 and described below.

2 shows a schematic cross sectional view of an embodiment of a fuel injection valve 10 designed according to the invention, which is particularly suitable for use in the fuel injection system 1 shown in FIG. 1.

The fuel injection valve 10 is in this case designed in the form of a direct injection fuel injection valve 10 which is used to inject the fuel directly into the combustion chamber 2 of the mixer compression type external ignition internal combustion engine. In this embodiment, the fuel injection valve is a fuel injection valve 10 which opens outward.

The fuel injection valve 10 includes an actuator 11 formed as a piezoelectric actuator 11 in this embodiment. The actuator 11 is encapsulated in the actuator housing 12 for stabilization and supported on the support 13 in the supply direction on the end side and on the shoulder 14 on the outflow side. The shoulder 14 is non-positively connected to the two-part valve needle 15.

While the inlet side first portion 16 of the valve needle 15 is supported on the shoulder 14, the second portion 17 is disposed separately from the first portion at the outlet side of the first portion 16. do. The first portion 16 of the valve needle 15 is loaded by a first return spring 18, which is arranged between the shoulder 14 and the sealing housing 19. The second portion 17 of the valve needle 15 is loaded by the second return spring 20, the force of the second return spring being less than the force of the first return spring 18, thereby providing a valve needle 15 The second portion 17 of) may vibrate relative to the first portion 16. This is for the weakening and debounce of the closing motion when the fuel injection valve 10 is switched quickly by the piezoelectric actuator 11.

The fuel injection valve 10 also includes a corgate tube seal 21 that protects the actuator 11 from fuel flowing through the fuel injection valve 10. Fuel is supplied in this embodiment through the central fuel supply 22 and flows through the fuel channel 23 into the housing body 24. In this case the fuel is guided into the recess 25 of the nozzle body 26 inserted into the housing body 24 through the sealing housing 19, in which the second part of the valve needle 15 ( 17) is also arranged.

The second portion 17 of the valve needle 15 comprises a valve closing body 27 integrally formed with the valve needle 15 or non-positively connected with the valve needle, the valve closing body being a nozzle body ( The sealing sheet is formed together with the valve seat surface 28 formed on the surface 26.

In the valve closing body 27 and / or the second portion 17 of the valve needle 15, a grinding surface 29 according to the invention is formed, which has a throttle action through the fuel injection valve 10. Is provided to be added to the fuel. The measures according to the invention are shown in more detail in FIGS. 3A, 3B and 4 and will be described further in the description below.

An excitation voltage is applied to the actuator 11 for the operation of the fuel injection valve 10, for example via an additionally unshown electrical line. The actuator 11, embodied as a piezoelectric actuator 11, is tensioned against the force of the first return spring 18. This causes the first portion 16 of the valve needle 15 to move in the stroke direction. The second part 17 of the valve needle 15, including the valve closing body 27, is also moved in the stroke direction against the force of the second return spring 20, whereby the valve closing body 27 has a valve seat surface ( 28) and fuel is injected.

When the actuator 11 is discharged, the first portion 16 of the valve needle 15 is returned to its starting position against the stroke direction by the force of the first return spring 18. This also reduces the load on the second part 17 of the valve needle 15, whereby the valve closing body 27 is again placed on the valve seat surface 28 and the fuel injection valve 10 is closed.

3A and 3B show an enlarged exploded view of the portion labeled III in FIG. 2 of the fuel injection valve 10 according to the invention in two different stroke positions of the valve needle 15. In this case, FIG. 3A shows, for example, a stroke position corresponding to the open position of the fuel injection valve 10, while FIG. 3B shows a stroke that appears when the fuel injection valve 10 is closed when the stroke of the valve needle 15 is small, for example. The location is shown. In all drawings the same parts are provided with the same reference numerals.

As described above, the second portion 17 of the valve needle 15 is at least one of directly connected to the valve closing body 27 integrally formed with the valve needle or the second portion 17 of the valve needle 15. It has a grinding surface 29. Preferably, a plurality of grinding surfaces 29 are regularly or irregularly distributed over the circumference of the valve closing body 27 and formed in the valve closing body.

The grinding surfaces 29 are for example formed in an elongated oval shape and are arranged alternately with the guide surfaces 30, which guide surfaces contact the corresponding surfaces 31 formed in the nozzle body 26. The guide face 30 and the corresponding face 31 guide the second part 17 of the valve needle 15 during the stroke movement. This prevents erroneous operation of the fuel injection valve 10 with subsequent jams by the offset of the valve needle 15.

As already mentioned above, the change in the opening angle α of the mixture cloud 8, 9 injected into the combustion chamber 2 is larger than the opening angle α ₁ at the start of the injection cycle at the end of the injection cycle. A mixture cloud 9 with an angle α ₂ is formed. The radial length of the grinding surface 29 of the valve closing body 27 defines a throttle gap 32 through which the grinding surfaces 29 release the width between the grinding surface 29 and the mating surface 31. It is formed to. In this case, since the width of the open cross section of the sealing sheet in the state where the fuel injection valve 10 is fully open is always larger than the width of the throttle gap 32 defined by the grinding surface 29, the grinding surface 29 is a preliminary one. Used as a throttle.

As shown in FIG. 3A, if the stroke of the valve closing body 27 is large, for example at its maximum position, a conical mixture cloud having a small opening angle α ₁ by means of a preliminary throttle obtained in the throttle gap 32. 8 may be injected into the combustion chamber 2.

The flow layer formed in the narrow gap of the grinding surface is thinner than the gap of the sealing sheet. This allows the fuel layer to deflect slightly and flow through the sealing sheet outwardly. The fuel layer does not flow through the sealing sheet region parallel to the wall, but slopes downward against the wall. Conical mixture clouds thus have a small opening angle.

Since a smaller excitation voltage is supplied to the actuator 11 of the fuel injection valve 10, when the valve closing body 27 is moved in the closing direction, the distance of the valve closing body 27 from the valve seat surface 28 is reduced. Narrower. If the gap is smaller than the gap of the grinding surface, flow through the sheet gap is forced to flow parallel to the wall. A larger opening angle of the conical mixture cloud is thus formed than in the first case.

4 shows a second embodiment of a fuel injection valve 10 designed in accordance with the invention as the same view as in FIGS. 3A and 3B.

In this embodiment the throttle function of the throttle gap 32 is independent of the grinding surface 29.

A guide region 33 is formed in the valve closing body 27 on the outflow side of the grinding surface 29, which guides the throttle gap 34 which always has the same width over the circumference of the valve closing body 27. Form. The ratio of the throttle by the sealing sheet and the throttle by the throttle gap 34 changes so that the throttle in the sealing sheet is advantageous when the fuel injection valve 10 is closed, thereby expanding the mixture cloud injected into the combustion chamber 22.

The throttle effect and subsequent expansion of the opening angle α of the mixture clouds 8, 9 are delayed in the closing process of the fuel injection valve 10 or by control of two separate stroke positions, for example via the actuator 11. Can be enhanced by

The present invention is not limited to the illustrated embodiment, but in any configuration of the fuel injection valve 10, different arrangements and valves of the spark plug 7 and the fuel injection valve 10 of the cylinder head 4 of the internal combustion engine are provided. Magnetic actuation of the needle movement can be used.

Claims (10)

An actuator 11 operatively connected with the valve needle 15 guided in the nozzle body 26, and a valve closing body 27 non-positively connected with the valve needle 15, In the fuel injection valve 10 for an internal combustion engine, the valve closing body 27 forms a sealing sheet together with the valve seat surface 28 formed on the nozzle body 26. The valve needle 15 and / or the valve closing body 27 comprises at least one grinding surface 29, the grinding surface of the valve needle 15 and / or the valve closing body 27. A cross section formed around the cross section between the at least one grinding surface 29 and the corresponding surface 31 formed on the nozzle body 26 in the open state of the fuel injection valve 10, the cross section being smaller than the open cross section of the sealing sheet. A throttle gap 32 is formed, The open cross section in the sealing sheet is closer to the cross section of the throttle gap 32 in the region of the grinding surface 29 upon closing of the fuel injection valve 10, while the opening angle of the mixture cloud is extended. Become, A guide region 33 is formed in the valve closing body 27 at the outflow side of the grinding surface 29, and the guide region has a throttle gap 34 which always has the same width over the circumference of the valve closing body 27. And an expansion of the throttle effect and subsequent opening angle of the mixture cloud (8, 9) is enhanced by the control of two separate stroke positions via the actuator (11). The method of claim 1, And at least one grinding surface (29) is provided in the guide region in the nozzle body (26). 3. The method of claim 2, A fuel injection valve, characterized in that a plurality of grinding surfaces (29) are provided which are arranged around the valve closing body (27) at regular or irregular intervals. The method of claim 3, wherein A fuel injection valve, characterized in that the guide surfaces (30) are formed between the grinding surfaces (29). The method of claim 4, wherein And the guide surfaces (30) cooperate with the corresponding surface (31) formed in the nozzle body (26) to form a guide of the valve closing body (27). The method according to any one of claims 1 to 5, The throttle action of the grinding surfaces (29) exceeds the throttle action of the sealing sheet in the open state of the fuel injection valve (10). delete delete The method of claim 1, Fuel injection valve, characterized in that the guide region (33) is formed integrally with the valve closing body (27). delete

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