KR100361442B1 - Fuel injection device - Google Patents

Abstract

The fuel injection device for the internal combustion engine of the present invention, in particular a two-stroke diesel engine, comprises an eccentric injection-nozzle tip 4 protruding into a combined combustion chamber, the nozzle tip being a plurality of discharge injections where the fuel can collide. A pocket drill hole 3 with a nozzle drill hole 13. The axis of at least the outer nozzle tip drill hole 13 in the drill hole row is inward in the radial direction. The fuel inflow condition is substantially the same as that of all the nozzle holes 13, so that the jet becomes stable. The inlet chamber 16 branches from the pocket drill hole 3 and becomes at least part of the nozzle drill hole 13, the inner diameter of the chamber being greater than the diameter of the nozzle drill hole 13 and the chamber being located within all the drill hole rows. It is designed so that at least the length ratio is similar to the nozzle drill hole.

Description

Fuel injection device {FUEL INJECTION DEVICE}

Fuel injection devices of this type are known from EP 0 606 371 B1. In the case of large two-stroke diesel engines provided with a central outlet valve in the cylinder head, the fuel injection value should normally be arranged in the combustion chamber circumference. The nozzle bores of the nozzle head are arranged such that the main injection direction is dispersed from one side of the nozzle head. In order to prevent the jet jet from being greatly dispersed in the transverse direction, the nozzle bores are aligned in the main jet direction instead of radially arranged with respect to the axis of the blind bore hole. This results in different lengths of the nozzle bores and different lengths of the boreholes crossing the outer periphery of the individual boreholes, while at the same time significantly changing the margin angles of the inner end region of the nozzle bore. Thus, the conditions for supplying fuel into individual nozzle bores vary widely, resulting in changes in throughput and throughput. In particular, the outer nozzle bore region of the borehole row comprising several nozzle bores arranged side by side is particularly unfavorable because the difference in the length of the walls across the outer periphery of the individual boreholes is wide. Due to the particularly high wall friction in the outer flank area, the flow is particularly unstable and the jetting jet is accompanied by only a small amount of air. This results in inadequate mixing, resulting in incomplete combustion, which leads to high fuel consumption and increased pollutants emissions.

The present invention relates to a fuel injection device for an internal combustion engine, in particular a large two-stroke diesel engine, comprising a nozzle head projecting into a corresponding combustion chamber and arranged eccentrically with respect to the axis of the combustion chamber, wherein the nozzle head is capable of passing fuel therethrough. A blind borehole, wherein the blind bore hole has a plurality of nozzle bores extending therefrom, wherein the nozzle bore can be opened and closed controlled by a slide member disposed in the blind bore hole, and the slide member Is axially slidable against the action of the return device by the pressure of the fuel, the nozzle bore facing the peripheral area of the blind borehole and arranged at the same height on the axis of the blind borehole. Arranged in a row to inject a common jet stream, the nozzle beam at least outside the borehole row It relates to a fuel injection device in which the axis of the air is inclined radially inward with respect to the axis of the blind borehole so that the divergent angle of the injection jets is acute.

1 is a cross-sectional view of an injector according to the invention of a large two-stroke diesel engine.

Figure 2 is a horizontal sectional view of the nozzle bore region of an embodiment with a hemispherical inlet chamber, through the nozzle head of a large two-stroke diesel engine injector.

3 shows an example with a ring-segment shaped inlet chamber corresponding to the hemispherical inlet chamber of FIG. 2;

4 is a cross-sectional view taken along the line IV / IV of FIG. 3.

It is therefore an object of the present invention to improve the apparatus of the type described above so that good combustion, ie low consumption of fuel and reduced pollution emission, can be achieved using simple and cost effective means.

The present invention allows at least some of the nozzle bores to be coupled to an inlet chamber extending from the blind borehole, the inner diameter of the inlet chamber being larger than the diameter of the nozzle bore and the inlet chamber being at least equal in length to all of the nozzle bores in the borehole row. Do it.

In this way almost equal proportions can be reliably achieved such that fuel is introduced without restriction in all nozzle bores. Advantageously, therefore, the inlet chamber allows the circumferential portions of the individual nozzle bores to achieve an indefinite outer length. Likewise, boreholes of approximately the same length can be achieved for both nozzle bores. Thus, the method according to the invention has a favorable effect on the averaging of the wall friction and the flow rate and the spray jet as a whole becomes stable. In particular, a relatively large amount of air intake is ensured by the jet jet as a result of stabilization in the outer nozzle bore region of the borehole row. This allows good mixing formation, i.e. good combustion, resulting in low fuel consumption, low emissions and reduced engine failure. Thus, the method according to the invention completely solves the above mentioned disadvantages.

Preferred embodiments and generally improved general methods are disclosed in the dependent claims. Therefore, the case where the inlet chamber is engaged with the outer nozzle bore of the borehole row is effective. Since so far this region of the outer nozzle bore has been characterized by the most unstable mixing flow, the maximum effect can be achieved by the inlet chamber according to the invention in the outer nozzle bore region of the borehole row.

In a first preferred embodiment, the inlet chamber consists of a recess in the nozzle head having a hemispherical shape in cross section. A hemispherical recess can form a preferably accurate and identical margin angle over the entire circumference of the nozzle bore. The hemispherical recesses are effectively arranged so that their centers are coincident with the axes of the respective bonded nozzle bores so that the nozzle bores are centered with respect to the inlet chamber to which the nozzle bores are coupled.

In addition, by forming the inlet chamber together with the hemispherical recess of the nozzle head, the nozzle head is thus not weakened by this and a simple coupling of each inlet chamber and each nozzle bore can be ensured.

A further advantage is that the hemispherical recess is arranged to form a staying stay in the two adjacent recess regions which can act as a guide stay for the slide member, thus preventing wear of the slide member. to be.

In another preferred embodiment of the general method, the inlet chamber is formed in the nozzle head with a ring-segment shaped recess. This is particularly economic in terms of production. In addition, in the above embodiment, the limit angle of 90 degrees to the transition portion between the inlet chamber coupled with the nozzle bore can be achieved relatively easily.

An additional advantage is that the intermediate group of nozzle bores facing other nozzle bores can be combined with the common inlet chamber without the nozzle head being too weak.

In an improved general method, a step-shaped cross-sectional enlargement, which is preferably formed by a step-shaped punch-out, may be provided at the outer end of the nozzle bore. This provides an axial interface around the outer end of the nozzle bore. It is stable to favor the flow of air, thereby ensuring the interference prevention of the jets. Thus, these disclosed methods reinforce the aforementioned basic advantages of the present invention.

Further preferred embodiments and effective improvements of the general method are set forth in the remaining dependent claims and the following illustrative description is set forth in more detail with reference to the accompanying drawings.

The main design and function of the large two-stroke diesel engine are known per se and no further explanation is required herein.

The injector shown in FIG. 1 consists of a cylindrical outer case 2 tapering forward, including a nozzle head 4 with a blind bore hole 3. The rear flange of the nozzle head 4 is supported by the front collar of the outer case 2. The rear end of the nozzle head 4 is connected to a guide bush 5 housed in the outer case 2, which guide bush 5 is with respect to the blind bore hole 3 of the nozzle head 4. A through-borehole 6 arranged coaxially. The through-bore hole comprises a stepped throat formed as a valve seat 7 which interacts with a valve body 8 projecting away from the shaft 9 arranged in the guide bush. The diameter of the valve body 8 is smaller than the diameter of the shaft 9 so that the ring space 10 surrounds the valve body 8 and results in the formation of the borehole 6.

The shaft 9 is connected to a central bore hole 11 connected to the fuel line, and fuel can be supplied through the bore hole, and the bore hole 11 passes through the plunge bore hole 12 to the ring space 10. ). The valve body 8 is pushed into the seal seat 7 by the action of a return spring (not shown) which interacts with the shaft 9. When the fuel pressure in the ring space 10 correspondingly increases, the valve bore 8 is lifted from the corresponding sealing seat 7 so that fuel can pass through and the blind bore hole of the nozzle head 4 ( 3) are connected.

The nozzle head 4 comprises a plurality of nozzle bores 13 arranged in their lower sections approximately equal in height and laterally aligned with the axis of the blind bore hole 3, said nozzle bores 13. By the fuel can be injected into the combined combustion chamber. A ring-shaped slide member connected to the valve body 8 by the rod 14 to ensure that fuel can no longer be discharged from the nozzle bore 13 after closing the passage controlled by the valve body 8. 15 is provided in the blind bore hole 3, and the lower end of the slide member 15 is opened so that the nozzle bore 13 opens when lifted from the valve seat 7 to which the valve body 8 is coupled. It forms a control edge that passes over the arrayed nozzle bores 13 and the nozzle bores 13 are closed when the valve body 8 is positioned opposite the valve seat 7. 1 shows this position.

In order to inject the required amount of fuel, a plurality of nozzle bores 13 are laterally offset from each other in the axial direction of the blind bore hole 3, which are arranged in FIGS. 2 and 3. It is arranged at approximately the same height as illustrated. The nozzle bores 13 may be arranged along the vertical axis, or may be slightly inclined outward as illustrated in FIG. 4. Since the jetting jet generated jointly by the nozzle bore 13 should not be classified too much, the nozzle bore 13 is not arranged radially with respect to the axis of the blind bore hole 3, but instead a radial line The angle of diversion, that is, the angle of dispersion, is smaller since it is arranged in the direction of the main jet with respect to.

If the nozzle bore 13 passes through the blind bore hole 3 without any change in cross section, different inflow relationships into and into the individual nozzle bores 13 can also occur very widely. . Two outer nozzle bores 13 of the borehole rows comprising four nozzle bores 13 provided parallel to the position may be considerably longer than the inner nozzle bores 13 and these outer nozzle bores across their circumference. (13) The length of the region also becomes different. Due to these conditions, incomplete combustion can occur, resulting in high fuel consumption and high emissions. In order to prevent this, the inlet chamber 16 spreading from the blind bore hole 3 is combined with the nozzle bore 13, and the inner diameter of the inlet chamber 16 is larger than the diameter of the nozzle bore 13.

In the embodiment of FIG. 2, a hemispherical recess 17 of the nozzle head 4 is provided to form an inlet chamber extending from the blind bore hole 3. The hemispherical recess 17 can be simply formed by an electrolysis, object cutting device operating according to the electric discharge machining (EDM) method. The nozzle bore 13 itself is simply drilled by the laser beam.

The hemispherical recesses 17 forming the inlet chamber are arranged such that their center is located on the axis of the combined nozzle bore 13. In this way, the inlet chamber to which the nozzle bore 13 is coupled is centered. This centering creates a limit angle in the transition region between the inlet chamber and the nozzle bore 13 and is guaranteed to be approximately equal to the diameter across the entire borehole diameter, as indicated by point 18 of FIG. 2.

The hemispherical recesses 17 located in the nozzle bores 13 adjacent to each other have a stay 19 located between the hemispherical recesses 17 adjacent to each other, and the stay 19 is a ring-shaped slide member ( It can act as a guide stay for 15), so that the ring-shaped slide member 15 can also be reliably supported in the inflow chamber region, which is advantageous in achieving longevity.

In certain cases the inlet chamber 16 is located in only two outer nozzle bores 13. In the preferred embodiment according to FIG. 2, the inlet chamber formed by the hemispherical recess 17 can be combined with all of the nozzle bores 13 to achieve particularly good combustion conditions, ie particularly preferred fuel consumption.

In the embodiment illustrated in FIG. 3, an inlet chamber 4 consisting of a ring-segmented recess 20 of the nozzle head 4 is associated with the nozzle bore 13. The radius of the ring-segmented recess 20 is such that the limit angle in the transition region between the inlet chamber and the nozzle bore 13 is as close as possible to 90 degrees, as indicated by (21) in FIG. 13).

It is conceivable to arrange its own inlet chamber formed by the ring segment 20 for each nozzle bore 13. In the illustrated embodiment, the common inlet chamber formed by the ring segment 20 is coupled with two central nozzle bores 13. The ring segment 20 corresponds to a ring groove section coaxial with the axis of the blind bore hole 3 of the nozzle head 4, the ring segment 20 having a diameter associated with two outer nozzle bores 13. It is bounded by smaller adjacent ring segments 20.

These outer ring segments 20 are arranged such that their centers are each positioned on the axis of the combined nozzle bore 13 and centered relative to the corresponding inlet chamber. This allows the inflow properties to be leveled across the borehole diameter. The center of the ring segment 20 coupled with the two nozzle bores 13 is located in the region between the two axes of the two coupled nozzle bores 13.

In the nozzle bore 13 outer end region of the embodiment illustrated in FIGS. 3 and 4, a perforation 22 having a larger diameter than the nozzle bore 13 is provided. The perforations 22 form a stepped cross-sectional enlargement with a ring region 23 aligned with the borehole axis and surrounding the borehole end. The perforation 22 ensures that jets injected from the nozzle bore 13 are not subjected to any interference.

It is of course also conceivable to provide the above-described type of perforation in the embodiment according to FIG. 2.

Although two embodiments of the present invention have been described in detail, the present invention is not limited thereto. Thus, part of the nozzle bore 13 is combined with an inlet chamber formed by a hemispherical recess 17 and the other part with one or several ring-segment shaped recesses 20, for example an outer nozzle bore ( 13 is conceived to engage the inlet chamber formed by the hemispherical recess 17 and the inner nozzle bore 13 with the common inlet chamber formed by the ring-segment shaped recess 20.

Claims (14)

As a fuel injector for internal combustion engines, especially large two-stroke diesel engines, A nozzle head 4 protruding into a corresponding combustion chamber and arranged to be eccentric with respect to the axis of the combustion chamber, The nozzle head 4 comprises a blind borehole 3 through which fuel can pass, The blind bore hole has a plurality of nozzle bores 13 extending from it, The nozzle bore 13 can be opened and closed controlled by the slide member 15 disposed in the blind bore hole 3, The slide member 15 is slidable in the axial direction against the action of the return device by the pressure of the fuel, The nozzle bore 13 is arranged in a row of boreholes facing the peripheral area of the blind bore hole 3 and disposed at the same height on the axis of the blind bore hole 3 to inject a common jet stream, The inclined angle of the nozzle bore 13 at least outside of the bore hole row is inclined radially inward with respect to the axis of the blind bore hole 3 so that the divergent angle of the injection jets is acute. At least a portion of the nozzle bore 13 is coupled with an inlet chamber 16 extending from the blind bore hole 3, The inner diameter of the inlet chamber 16 is larger than the diameter of the nozzle bore 13, At least part of the inlet chamber 16 is formed by a ring-segmented recess 20 of the nozzle head 4, The recesses 20 have different diameters such that the lengths of all the nozzle bores in the borehole rows are the same. Fuel injector. 2. The fuel injector of claim 1, wherein the case length of the nozzle bore does not vary along the circumference. The fuel injector of claim 1, wherein all nozzle bores have the same length. The fuel injection device according to claim 1 or 2, wherein the inlet chamber (16) is coupled with a nozzle bore (13) at least outside of the borehole row. The fuel injection device according to claim 1 or 2, wherein at least part of the inlet chamber is formed in the nozzle head (4) with a recess (17) having a hemispherical cross section. 6. A fuel injection device according to claim 5, wherein an inlet chamber formed of said hemispherical recess (17) is associated with each nozzle bore (13). 6. Fuel injection device according to claim 5, wherein the center of each hemispherical recess (17) forming the inlet chamber is located on the axis of the corresponding respective nozzle bore (13). 6. A fuel injection device according to claim 5, wherein a guide stay (19) is provided between adjacent inlet chambers formed by said hemispherical recesses (17). delete 2. The fuel injection device of claim 1, wherein a group of nozzle bores located in the middle of the plurality of nozzle bores is associated with a common inlet chamber formed of a ring-segment shaped recess (20). 3. The center of the ring-segmented recess 20, which forms an inlet chamber coupled with the nozzle bore 13, is arranged on the axis of the corresponding nozzle bore 13. Fuel injector. 3. The fuel injector of claim 1, wherein the side wall of the nozzle bore and the corresponding inlet chamber are at an angle of at least 90 degrees. 4. The fuel injection device according to claim 1 or 2, wherein a stepped cross-sectional enlarged portion formed by a punched-out part (22) is provided at an outer end of the nozzle bore (13). 14. A fuel injection device according to claim 13, wherein the perforations (22) comprise an inner boundary surface formed along an axis perpendicular to the corresponding nozzle bore (13).