EP3341607A1

EP3341607A1 - Common rail distributor rail

Info

Publication number: EP3341607A1
Application number: EP15757115.9A
Authority: EP
Inventors: Christoph KRAUTER; Steffen Jung
Original assignee: Nova Werke AG
Current assignee: Nova Werke AG
Priority date: 2015-08-24
Filing date: 2015-08-24
Publication date: 2018-07-04
Also published as: US20180180004A1; WO2017031601A1; JP2018525568A; CN108350843A; KR20180042218A

Abstract

A common rail distributor rail (2) for supplying an internal combustion engine with fuel has an inner pressure pipe, an outer casing (4) and clamps (5) for the connection of high-pressure lines. The clamps (5) are securely connected to the outer casing (4), in particular by thermal joining, and thereby form a double-walled system with pressure-tight sealing of the casing.

Description

COMMON RAIL DISTRIBUTION RAIL

The invention relates to the field of fuel supply of internal combustion engines and in particular to a common rail distribution rail.

Common rail injection systems are used to supply fuel to internal combustion engines, in particular diesel engines. Such an injection system has a distributor rail with a pressure tube, which is fed by a high pressure pump via a supply line with fuel. The distribution rail has a plurality of outlets, each of which feed injector lines for supplying injection valves of a motor. The injector lines may be connected to the pressure tube with collars, typically with the injector tubes bolted to the collars, and the collars welded to the pressure tube. A line connection of an injector line is connected to a pressure pipe connection of the pressure pipe, which connection must withstand the operating pressure of the system.

US 4,832,376 shows such a departure, in which a line connection is pressed with an outer cone against an inner cone of a pressure tube. A corresponding pressing force is generated by a screw connection of the line connection in a Bride. The sealing of pressure-carrying volumes of the injection system is thus done by the Koni pressed against each other (and not in the area in which the Bride surrounds the pressure tube). If the bridge is attached to the pressure tube, the position of the bridge in the axial direction of the bridge must be Pressure tube must be aligned with high precision to the position of the inner cone. Therefore, it is advantageous if the Bride is displaceable when connecting the pipe connection to the pressure tube. For ship engines, for reasons of safety, the various lines of the injection system are guided in a double-walled manner, in particular the injector lines and the distribution rail itself. For this purpose, the pressure tube has an outer jacket. Thus, leakage of the fuel can be safely avoided. Alternatively or additionally, an operationally occurring fuel surplus of the injectors can be recycled by these spaces.

Typical operating pressures for the pressure pipe are over 1000 or over 2000 bar.

In the case of a double-walled distribution rail, the problem arises of connecting both the injector lines subjected to high pressure to the pressure pipe and of making the intermediate space pressure-resistant. Corresponding clips must therefore connect the injector leads to the pressure tube in a pressure-tight manner and also be connected to the jacket in a pressure-tight manner. In known systems, a pipe section is used as part of the shell between each two bridges and sealed with sealing elements, for example O-rings with respect to the Briden. The totality of such pieces of pipe and Briden forms the jacket. By the jacket is multi-part, and the Briden allow a certain axial play of the pipe sections, when mounting the distribution rail, an axial position of the Briden along the pressure tube to the axial position of the pressure pipe connections can be adjusted. The disadvantage here is that the parts only get their final position to each other during assembly of the distribution rail on the engine, and only then the compressive strength of the shell can be tested. It is therefore a possible object of the invention to provide a common rail distribution rail, which the above-mentioned disadvantages popular.

Another possible object is to provide a common rail distribution rail, which is easy to install and transport.

Another possible object is to provide a common rail distribution rail, which is double-walled and in which an outer jacket can be checked for leaks even before mounting on a motor for the operation of the distribution rail, and the tightness up to Assembly on the engine and after installation on the engine is maintained.

Another possible object is to provide a common rail distribution rail, which is einlach and thus inexpensive to produce in individual pieces or in small batches.

Another possible object is to provide a common rail distribution rail which is double-walled and permits reliable mounting of connections to an inner pressure pipe.

Another possible object is to provide a common rail distribution rail which is easy to repair, especially in the event of damage to a leakage pipe.

At least one of these objects solves a common rail distribution rail according to at least one of the claims.

A common-rail distributor rail for supplying an internal combustion engine with fuel according to a first aspect of the invention has an inner pressure tube, an outer jacket and bridges for connecting high-pressure lines such as injector lines. The Briden are firm with the outer coat connected, in particular by thermal joining, thereby forming a seal of the shell.

Thus, the parts of the jacket are no longer used in the Briden and sealed with O-rings, but form a firm connection with the Briden. The mentioned parts of the distribution rail - pressure tube, casing pipe and Briden - bi lden a solid structure. This is inherently fixed with respect to all six (translational and rotational) degrees of freedom. The distribution rail can be manufactured, tested, transported and assembled as a unit. In particular, a tightness test to a certain pressure, for example, 200 bar, in manufacturing possible and can then be considered secure - in contrast to a coat that is formed only during assembly on the engine and the associated assembly of the individual parts of the shell. Here and in other places is mentioned by connectable high pressure lines. It will be understood, however, that other high pressure components such as e.g. Flow limiter or pressure transducer can be connected.

By the jacket tube with the Briden is stiff in itself, so no mutual displacement of these elements allows Beißkantenabdichtungen be present between the pressure tube and connecting lines, such as injector as connection partner Beißkantenabdichtungen. In these, one side of such a connection can be a plane surface, so that the mutual position of the connection partners, in particular in the axial direction of the pressure tube, is not determined by the connection. The position of the bridges is defined by the firm connection with the jacket pipe, so that the position does not have to be determined by the connection with the pressure raw r. The axial direction of the pressure tube can also be called the longitudinal direction of the pressure tube, and is identical to the axial direction or longitudinal direction of the jacket as well as the distribution rail as a whole. Thermal joining includes in particular welding or soldering. As an alternative to thermal joining, the bridges can also be glued to the jacket.

According to a Ausmrungsform have the Briden with the jacket each circumferential joints.

In particular, therefore, the Briden are with the coat rundverschwe s s or round soldered. That is, it is on both sides of the Bride along the Urnfangs of the shell substantially circular weld or soldering between Bride and mantle before.

This has the consequence that no additional parts are required for sealing. It is created during manufacture of the joint a pressure-tight seal between the jacket and Bride. This can be checked for leaks, the tightness is ensured even after transport and installation of the distribution rail.

The jacket or the intermediate space must remain tight at pressures of, for example, 200 bar or 500 bar (in the intermediate space).

The pressure tube itself is not welded. As a result, its strength is not impaired. The materials for jacket tube and Bride can be selected for optimal welding properties.

According to one embodiment, the jacket is formed by a continuous jacket tube. A single jacket tube thus carries essentially all Briden. For a simple and stable construction of the distribution rail is realized. The jacket pipe is self-supporting and does not rely on the support by pressure tube and Briden. The pressure tube can be stored to a large extent "floating" in the jacket tube: it can be spaced by spacer elements of this, Such spacers can be inserted spacers, spacers, inwardly facing webs of the casing tube (profiled casing) and / or outwardly facing webs of the pressure tube Between the spacers, there is a gap for discharging leaking fuel, and in the case of webs as spacers, the space is formed by grooves located between the lands.

The gap provides a over the length of the distribution rail substantially constant leakage cross section - in contrast to a construction with individual Mante lrohr abs ch cut, which are each used in Briden. This is particularly advantageous in the derivation of injector leakage, that is to say in the case of a control quantity return from the injection valves. A mutual fixation between pressure tube and jacket tube is done via high pressure lines used respectively their connections on the pressure tube. Alternatively or additionally, the mutual fixation can be done by at least one fixing element. This can brace pressure tube and casing tube against each other, for example by the fixing element is designed as a screw which rotates in a thread in a Bride and presses against the pressure tube. In this case, a centering connection, for example by means of mating conical screw and pressure tube present. ,

According to one embodiment, the jacket is formed by a series of individual pieces of pipe, which are connected to each other by the bridges. The Distribution rail can also be made by welding the Briden with the pipe sections of the jacket tube, creating a solid structure, with the above-mentioned properties. According to one embodiment, pressure pipe connections are formed on the pressure pipe, which are provided for connection to a high-pressure line through a Beißkantenabdichtung.

For example, a pressure pipe connection has a flat surface against which a biting edge of a line connection of a high-pressure line can be pressed a biting edge realized seal ("Beißkantenabdichtung") have abutting sealing surfaces of two metallic components on an edged or bead-shaped survey that leads to a sealing plastic deformation along the survey when tightening the components against each other.

Alternatively, there may be a cone connection or lenticular connection between the line connection and the pressure pipe connection.

In a conical connection, for example, a precise tolerance between the pressure pipe connections on the pressure tube and the welded Briden must be complied with, over the entire length of the distribution rail, which may be up to 5 m for large engines, for example.

A common rail distribution rail for supplying an internal combustion engine with fuel according to a second aspect of the invention, which in combination with The other aspects but also independent of the other aspects can be realized, has an (inner) pressure tube and Briden to connect. of high pressure lines. The Briden are made by cutting out of a flat material. Optionally, the common rail distribution rail may also have an outer jacket.

It is thus a - in contrast to castings - flexible production of Briden different shapes possible. Brids can be designed and manufactured to order specific and cost-effective according to customer requirements for small series and single pieces of distribution rails. The flat material may be a metal plate, in particular a steel plate, with a maximum thickness of, for example, 4 cm to a sem or more. A single Bride can be made from a plate with a thickness of for example between 2cm and 4cm, a double Bride from 7cm to 15cm thick material. Overall, so Briden can have a thickness of 2cm to 15cm.

Cutting can be done for example by water jet cutting, laser cutting or flame cutting. The plane of the sheet from which the bridge is cut is normal to the axial direction of extension of the distribution rail, the pressure tube and the shell. Further, by using a rolled steel instead of cast steel, better material properties of the beams can be achieved, for example, better (notch) impact resistance, elongation at break, machinability, weldability, no casting defects, etc. Such cut-out pieces can be blanks forming the final shape of the billet Bridges to be reworked.

Alternatively, the braids can be made by:

• Producing a profile bar with a contour corresponding to a contour of the bridges in the axial direction of the distribution rail. This can be, for example done by extrusion. The profile bar is in this case an extruded body.

• Cutting pieces of profile bar into blanks of a length corresponding to a desired length of the bars in the axial direction of the bar.

• Finishing the blanks to the final shape of the brids.

This allows Briden to be manufactured inexpensively at high volumes.

According to one embodiment, the Briden elements for securing the Briden and thus the distribution rail on a motor.

In this case, therefore, the bridges have a double function in that they form both the connections of the high-pressure lines and also serve for fastening the distribution rail to the engine. The brackets may have other application specific mounting elements, for example for attaching a cover, cables or cable channels.

According to one embodiment, at least one of the bridles is made of a flat material having a different thickness than the other bridles, in particular of at least twice the thickness of the other bridles.

Thanks to the production of the bridges made of flat material, the extension of the bridge in the axial direction of the distribution rail can be determined simply by selecting the thickness of the flat material. A Bride with greater extension than others can be used to connect multiple pressure lines (supply and / or outlets), and / or for connection to other elements.

Further, brids of various shapes can be inexpensively manufactured by correspondingly cutting out various contours from the flat material. Thus, the distribution rail Briden different shapes, considered in cl he projection along the longitudinal direction or axial direction of the distribution rail, have.

Similarly, if the bridles are made by cutting off a section bar, at least one bridle can be made by cutting off a length of the section bar having a first length other than a length of other bridles. In particular, the first length is at least twice the length of other bridges. The length is measured along the longitudinal direction of the profile bar. This direction with respect to the bridge corresponds to the longitudinal direction of the distribution rail in the mounted state.

A common rail distribution rail for supplying an internal combustion engine with fuel according to a third aspect of the invention, which can be realized in combination with the other aspects but independently of the other aspects, comprises an inner pressure tube, an outer jacket and Brides for connecting High pressure lines on. In this case, a portion of the pressure tube, in particular at least one end of the pressure tube, and one of the bridges are positively connected to each other and forms this positive connection an anti-rotation of the pressure tube with respect to this Bride.

Alternatively or additionally, the pressure tube - even at a location other than at one end - be positively connected to each other, and thus the rotation can be formed. This prevents twisting of the pressure tube when, for example, a pipe screwed axially to the pressure pipe or a sealing neck has to be screwed to the pressure pipe. It can be arranged on only one end or at both ends of the distribution rail, a rotation. If there are two anti-rotation, the one can be designed so that they have a Displacement of pressure tube and Bride in the axial direction allows, and the other, so that they do not allow such a shift.

The rotation can be realized by appropriate shaping of the pressure tube and the Bride, for example by lying on the circumference of the pressure tube flattened point, or by a prismatic shape of the pressure tube and the inside of the Bride. Alternatively or additionally, in each case a groove in pressure tube and Bride be present, in which a feather key is inserted. The anti-twist device can be designed for a tightening torque of up to 200 Nm.

According to one embodiment, there is a fixing element, which eliminates a game of rotation.

The fixing eliminates any remaining game of anti-rotation by the pressure tube clamped against the Bride, this can be done in many ways, for example by means of a wedge or a fixing screw, which is guided in the Bride and screwed against the pressure tube.

There may be another fixing element which fixes a mutual position between at least one bridge and the pressure tube in the axial direction. It can also be realized this axial fixation by the identical fixing, which eliminates the game of rotation.

A common-rail distribution rail for supplying an internal combustion engine with fuel according to a fourth aspect of the invention, which can be realized in combination with the other aspects but also independently of the other aspects, has an (inner) pressure pipe and Briden for connecting high-pressure lines , There is a continuous leakage pipe for the discharge of backflowing fuel. Optionally, the common rail distribution rail may also have an outer jacket.

Such a leakage pipe is used, for example, to absorb an inherent return of fuel from the injection valves ("injector backflow") .The fuel can be supplied by its own return lines, which can also lead through the bridges themselves to the leakage pipe or directly into the leakage pipe.

By having a through leak tube, it can be easily assembled and disassembled, and it can be fixed to allow assembly / disassembly without having to disassemble the brackets and thus the entire rail - unlike systems in which A leakage line consists of several sections, each leading from Bride to Bride and are plugged into the Briden. Thus, the leakage pipe can be easily replaced if it is damaged.

According to one embodiment, the leakage pipe is fastened with hollow connecting elements to the bridges, wherein these connecting elements are each provided to direct refluxing fuel into the leakage pipe.

Connecting elements are, for example, hollow screws or hollow rivets. The connecting elements thus serve both for securing the leakage pipe as well as a supply line. The leak tube can also be welded or soldered to the bridges, but it must be prevented that warps the distribution rail. Alternatively, the leak tube can be glued to the Briden.

According to one embodiment, the leakage pipe is a profiled pipe, has at least one flat wall section in cross-section, and is flat therewith Wall section mounted against the bridge. In particular, the leakage tube is a square tube.

Thus, simple designed sealing points to the leakage pipe can be realized by the flat wall portion is mounted against a flat part of the Bride and a sealing element, such as a sealing ring between the two parts is arranged.

Typically, the leakage system and in particular the leakage pipe and the connected lines are designed for a pressure resistance of up to 50 bar.

Further preferred embodiments emerge from the dependent claims. In the following, the subject invention will be explained in more detail with reference to preferred embodiments, which are illustrated in the accompanying drawings. Each show schematically:

Figure 1 is a view of a distribution rail;

Figure 2 shows a longitudinal section through one end of the distribution rail with pressure tube and casing pipe;

Figure 3 is a plan view of the end of the distribution rail;

Figure 4 shows a longitudinal section through one end of a distribution rail with pressure tube and jacket tube and other elements;

Figure 5 shows a cross section through a distribution rail in the region of a Bride, with a conical connection;

6 shows a cross section through a Bride in the area of a

rotation; and

Figure 7 shows a cross section through a distribution rail in the region of a Bride, with a connection with a biting edge. Basically, the same parts are provided with the same reference numerals in the figures. Figure 1 shows a view of a distribution rail 2. Visible is a jacket tube 4 with strung thereon Briden 5. The Briden 5 are each welded to the circumference of the casing tube 4 with (circular) welds 41 with the jacket tube 4. The jacket tube 4 may be in one piece over the entire length of the distribution rail 2, or as a multi-part jacket, with individual sections of the shell each extend from a Bride 5 to the adjacent Bride 5 or even to a more distant Bride 5. The Briden 5 serve here both for connecting pressure lines as well as for fixing the distribution rail 2 to a motor (not shown).

FIG. 2 shows a longitudinal section through and FIG. 3 shows a plan view of sections of the distribution rail 2. A pressure pipe extending in the casing pipe 4 is not shown for the sake of clarity. In addition to the elements already described, pressure pipe connections 31 are still visible, at which outgoing high-pressure lines (injector lines) can be connected to the pressure pipe 3. In the area of a left in the image arranged double cross 5 'an anti-rotation 55 is arranged. The anti-rotation device 55 is formed here as a flattened part of the circumference of the opening for the pressure tube. FIG. 6 shows the anti-twist device 55 in a view (in the axial direction) of the double strap 5 'alone. The anti-rotation device 55 forms with a correspondingly shaped flattened region of the pressure tube 3 a positive connection and fixes a rotational position of the pressure tube 3 with respect to the double-Bride 5 '.

FIG. 4 shows a further longitudinal section through one end of a distributor rail 2 with pressure tube 3 and jacket tube 4 and further elements which are connected to the distributor rail 2: on the bridges 5, via intermediate pieces 7 (FIG. 7) each double-walled injector lines or high-pressure lines or other components such as flow limiters or Dmckaufhehmer be connected. Inner pressure lines of the high-pressure lines are connected with cone connections pressure-tight to the pressure tube 3. A supply line is also connected via a cone connection to the pressure tube 3. The high pressure lines and supply lines are not considered part of the distribution rail 2.

The pressure tube 3 has an upper flattened region with a pressure-tube connection 31, and a lower flattened region 35, which cooperates with the flattened region of the anti-rotation device 55 on the bridge, and thus realizes the anti-twist protection.

The jacket tube 4 is shown here to the very left throughout. If the double link 5 ', as shown in FIG. 2, also has the anti-rotation device 55, which is in fact formed on a constriction extending inwards to the pressure tube 3, then the continuous jacket tube 4 would only drive up to this constriction from the right. The left of the constriction remaining short section of the jacket is then formed by a separate piece of pipe, which is typically also welded to the double strap 5 '.

FIG. 5 shows a cross section through a distribution rail 2 in the region of a bridge 5. In addition to the elements already described, the following are visible here:

A pipe region 51, at which the bridge 5 is connected to the jacket pipe 4. Therein, a cross-section of the jacket tube 4 is visible, with inwardly directed webs 33 for spacing the pressure tube 3, and corresponding grooves 34 for forming a gap.

A connection region 52, to which a high-pressure line can be connected to the bridge 5 via an intermediate piece 7. In this case, a line connection 61 of the high pressure line with an outer cone against a pressure pipe connection 3 1 of the pressure tube 3 with an inner cone 32gepresst. The intermediate piece 7, on the one hand, presses the line connection 61 against the pressure pipe connection 31, and, on the other hand, forms a transitional space between the interspace of pressure pipe 3 and jacket pipe 4 and a gap between inner pipe and outer pipe of the high-pressure line.

• A mounting portion 53 for attaching the Bride 5 to a motor or other carrier object.

• A leak tube carrier 54 for attaching a leak tube 8. This may receive fuel flow from the injectors via return lines (not shown) and continue to return to the source of crudes.

The leakage tube 8 is mounted by means of a hollow screw 81 on Leckagerohrträger 54, with optional sealing elements between the hollow screw 8 1 and leakage tube carrier 54, if the sealing effect of the screw thread is insufficient. The Leckagerohrträger 54 may be formed integrally formed on the Bride 5. Fuel flows through the return line into the hollow screw 81 and through a bore at the long order of the hollow screw 81 into the leakage pipe. 8

A closure element 93, here in the form of a screw, can be opened in case of service and can be used to limit the location of a leak.

FIG. 7 shows a cross-section through a distribution rail 2 in the region of a ride 5, similar to FIG. 5. In addition to the elements already described, a connection with a biting edge is shown instead of a cone connection of the high-pressure line: a line connection 61 of the high-pressure line is designed as a biting edge and is through the intermediate piece 7, which, for example, with the

Bride is screwed against a flat surface at the connection portion 31 of the pressure tube 3 is pressed.

Claims

PATENT CLAIMS

Common rail distributor rail (2) for supplying an internal combustion engine with fuel, comprising an inner pressure pipe (3), an outer jacket and bridges (5) for connecting high-pressure lines,

characterized in that

the bridges (5) are firmly connected to the outer shell, in particular by thermal joining, and thereby form a seal of the shell.

Distributor rail (2) according to claim 1, wherein the Briden (5) with the jacket each have circumferential joints (41).

Distributor rail (2) according to claim 1 or 2, wherein the jacket is formed by a continuous jacket tube (4).

A distribution rail (2) according to claim 1 or 2, wherein the casing is formed by a series of individual pipe pieces, which are connected to each other by the bridges (5).

Distributing rail (2) according to one of the preceding claims, wherein pressure pipe connections (31) are formed on the pressure pipe (3), which are provided for connection to a high pressure line by a Beißkantenabdichtung, in particular by a pressure pipe connection (31) has a flat surface against which a biting edge of a line connection (61) of a high-pressure line can be pressed.

Distributor rail (2) according to one of the preceding claims, wherein the bridges (5) are made by cutting out of a flat material or by cutting off a profile bar.

7. distribution rail (2) according to claim 6, wherein the Briden (5) elements (53) for securing the Briden (5) and thus the distribution rail (2) on a motor.

Distributor rail (2) according to one of claims 6 or 7, wherein at least one of the bridges (5) is made of a flat material having a different thickness than the other bridges (5), in particular at least twice the thickness of the other bridges (5). , 9. Distributing rail (2) according to one of claims 6 or 7, wherein at least one of the bridges (5) is made by cutting a piece with a first length of a profile bar, and this first length has a different length than the other Briden (5 ), in particular at least twice the length of the other Briden (5).

10. Distributor rail (2) according to one of the preceding claims, wherein at least one section, in particular one end of the pressure tube (3) and one of the bridges (5) are positively and / or non-positively connected to each other and this positive connection an anti-rotation of the pressure tube (3 ) with respect to this bridge (5).

1 1. Distributor rail (2) according to claim 10, wherein a fixing element (92) is present, which eliminates a game of anti-rotation. 12. Distributor rail (2) according to one of the preceding claims, wherein there is a further fixing element, which fixes a mutual position between at least one Bride (5) and the pressure tube (3) in the axial direction, and wherein in particular the further fixing element is identical to a Fixing element (92), which eliminates a game of anti-rotation.

13. Distributor rail (2) according to one of the preceding claims, comprising a parallel to the pressure tube (3) extending and on the Briden (5) fixed through the leakage pipe (8) for the discharge of refluxing fuel. 14. Distributor rail (2) according to claim 13, wherein the leakage pipe (8) is fastened to the bridges (5) with hollow connecting elements (81), wherein these connecting elements (81) are each provided for flowing back-flowing fuel into the leakage pipe (8). to lead. 15. Distributor rail (2) according to claim 13, wherein the leakage pipe (8) is a profile tube, in cross section has at least one flat wall portion, and is mounted with this flat wall portion against the Bride (5), in particular wherein the leakage pipe (8) a Square tube is.