KR20060060614A - Fuel supply device with a pressure accumulator tube closed by accumulator cover - Google Patents

Abstract

A fuel in the form of a common rail system, comprising at least one pressure accumulator chamber in a pressure accumulator unit, at least the end face of which can be closed by an accumulator cover, and in which all functional units are integrated with respect to fuel supply and transfer in the accumulator cover. In the supply device, in order to facilitate access to the functional unit and to maintain the advantage of pressure amplitude attenuation in the functional unit of the accumulator cover, in particular in the 3 / 2-way valve and the pressure tube, the accumulator cover has two parts with a sealing element. Consists of two modules in the form of a control unit, wherein the sealing element is arranged in a sealing engagement with the accumulator unit, and the control unit can be arbitrarily arranged within the pressure tube between the sealing element and the fuel injector to be fueled. have.

Description

FUEL SUPPLY DEVICE WITH A PRESSURE ACCUMULATOR TUBE CLOSED BY ACCUMULATOR COVER}

1 is a front view of an accumulator cover according to the invention with an accumulator unit disposed in a sealing element of the high pressure accumulator unit.

FIG. 2 is a side view of the accumulator cover according to FIG. 1 in which a separating seam between two modular parts is shown; FIG.

3 is a schematic view showing the arrangement of the accumulator unit of the accumulator cover according to the invention in a fuel injector;

4 shows a schematic representation of the arrangement of the accumulator unit of the accumulator cover according to the invention in a pressure tube between the sealing element and the fuel injector.

* Description of the symbols for the main parts of the drawings *

1: fuel injector 2: pressure tube

3: accumulator cover 4: sealing element

5: control unit 6: support part

7: screw

The present invention is a fuel supply device in the form of a common rail system for supplying fuel to a cylinder fuel injector of an internal combustion engine via a pressure pipe, the pressure pipe having at least one end face in at least one pressure accumulator unit which can be closed by an accumulator cover. A fuel supply device comprising a pressure accumulator chamber and in which all functional units are integrated with respect to fuel supply and transfer within the accumulator cover.

In DE 101 57 135 A1, for example, a fuel supply device according to the preamble of claim 1 is known.

The use of common rail systems in large diesel internal combustion engines is problematic due to the length of the pressure accumulator unit required in relation to the constant accumulator pressure for all cylinders along the engine axis. For this reason, the pressure accumulator unit is implemented as two or more separate accumulator units connected to each other by a connecting tube. The accumulator units may each be connected to two or more fuel injectors and may be pressured by a high pressure pump. By installing the accumulator covers with integrated all functional units on each of the two end faces with respect to fuel supply and transfer, the improvement in the existing engine type with a common rail injection system is significantly simplified.

As mentioned above, all functional units, such as quantity limiting valves, are arranged on the accumulator cover, which makes the modular construction simple and also increases the operating safety, because the memory unit, and thus the total pressure This is because the accumulator unit does not receive external forces from the support and hydraulic connections. The support and the connection are now housed by a modularly formed accumulator cover.

Fuel from each accumulator unit reaches the accumulator cover of the above manner through the perfusion limiter. The accumulator cover includes a plurality of functional units. For example, the injection is controlled via a 3/2 directional valve which is actuated indirectly via a 2/2 directional valve which is switched directly or electromagnetically controlled. From the 3 / 2-way valve the fuel reaches the connection of the pressure tube, as is known, through each pressure injector consisting of, for example, a conventional needle valve.

As noted above, this accumulator cover includes one or more 3 / 2-way valves (including 2 / 2-way valves for controlling 3 / 2-way valves in some cases), both limiting valves, all hydraulic connections, and internal combustion engines. A support for the entire accumulator element and a fixture and seal of the tubular accumulator body.

The preferred combination of a spring loaded fuel injector and a 3/2 directional valve disposed within the accumulator cover greatly simplifies the installation of existing engine types with a common rail injection system, and by installing the accumulator cover directly in the pressure accumulator unit, In particular, in the functional unit of the 3 / 2-way valve of the conventional common rail injection system, the pressure vibration which occurs especially at the end of injection is avoided.

However, there is a risk of wear of some components, especially in accumulator covers so complicated.

In such a case, at least the complete accumulator cover should in most cases be separated or replaced with the complete accumulator unit.

Upon replacement of the accumulator cover, the high pressure sealing surface between the accumulator unit and the accumulator cover is separated, which necessitates a new tightness test in service or creates a risk of leakage. It is relatively complicated to assemble / disassemble functional units of the accumulator cover to date which are in a totally high pressure state.

It is an object of the present invention to provide a fuel supply device in the form of a common rail system, while the advantages of pressure amplitude attenuation for the accumulator cover, in particular the functional units of the 3/2 directional valve and the pressure tube, are retained, but the aforementioned disadvantages of the accumulator cover are eliminated. To provide.

This object is achieved according to the invention by the features mentioned in the characterizing part of claim 1.

The accumulator cover consists of two modules in the form of a sealing element and a control unit in two parts, the sealing element being arranged in sealing engagement with the accumulator unit, and the structural unit of the control unit including all functional units and the sealing element of the accumulator cover. By separation and by the spatial separation of the two modules, ie by the placement of the control unit between the accumulator unit and the fuel injector, a control unit is arbitrarily arranged between the sealing element and the fuel injector to be fueled in relation to the pressure tube, thereby providing a positive The attenuation of the above-mentioned pressure amplitude is maintained, in particular at the end of the injection, in particular, and the aforementioned negative effects are eliminated.

In particular, accessibility to the control unit is remarkably improved by spatial separation of the control unit and the sealing element, so that the assembly / disassembly of the control unit in the high pressure coupling state becomes very easy.

Seal element and control unit when the diameter of the pressure tube, which is connected to the sealing element directly in the high pressure accumulator unit or can be integrated in the accumulator tube between the high pressure accumulator unit and the fuel injector or directly to or in the fuel injector, is about 7 mm. In the range of settings in which the spatial separation of is designed from 0 mm to 2000 mm, different assembly positions, i.e., the arrangement of the control unit, can be provided, so that optimum use of the available installation space is possible.

In any case, the sealing element is not separated from the sealing surface of the associated high pressure accumulator unit when the control unit or the functional unit of the control unit is replaced, thereby minimizing the risk of leakage.

By the above provision of the spatial separation of the sealing element and the accumulator cover, even in the case of extremes spaced 2000 mm, the advantage of pressure amplitude attenuation is maintained, especially in the 3 / 2-way valve and pressure tube, because the control unit This is because they are always close enough to the sealing element at certain diameters.

In addition, the best hydraulic matching of the fuel supply device is possible by pre-connection or post-connection of the hydraulic volume in the pressure pipe, so that the injection progress shaping, multiple injection, and the like are possible.

This has several positive effects on internal combustion engines such as smooth combustion, improved operating conditions, low fuel consumption and reduced emissions.

In addition, a separate, optimized part manufacturing is made, which part comprises a high pressure accumulator unit, a pressure tube, a sealing element, a control unit and a fuel injector. The manufacturing method is improved and in some cases it is possible to disassemble the control unit without disassembling the pressure tube.

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

The pressure accumulator unit is formed of tubular parts with or without inserts as is known, with end faces sealed by the accumulator cover 3 according to FIGS. 1 to 4 and each not shown at approximately the height of the cylinder head. It is arranged along the internal combustion engine.

Each accumulator unit is connected to one or more fuel injectors 1, which are generally electronically controlled by one or more pressure tubes 2.

In a preferred case, one accumulator unit is provided for each of the two cylinders to be operated. When the number of cylinders is odd, the accumulator unit, which can be arbitrarily arranged, operates only one cylinder. Depending on the engine type and application, the individual accumulator units connected to each other are filled by two to six high pressure pumps.

As mentioned above, the fuel reaches the accumulator cover 3 through the perfusion limiter from each accumulator unit. The accumulator cover 3 comprises a plurality of functional units. The injection can be controlled via a 3/2 directional valve which is switched directly or indirectly via an electromagnetically controlled 2/2 directional valve. Since the functional principles of the individual functional units are sufficiently known to those skilled in the art at least in the foregoing prior art, they are not described in detail here.

1 and 2 the accumulator cover 3 according to the invention consists of a control unit 5 and a sealing element 4 comprising two separate parts, namely all the functional units described above.

The sealing element 4 seals the end face of the high pressure accumulator element, which is not shown here. For this purpose the sealing element is fixedly connected to the tubular part of the high pressure accumulator element by a plurality of screws 7. The sealing element 4 is again equipped with a control unit 5 and in this embodiment is likewise fastened to the sealing element 4 by screws 8.

As mentioned above, the control unit 5 comprises one or more 3 / 2-way valves (and optionally 2 / 2-way valves for controlling the 3 / 2-way valves), both limiting valves and all hydraulic connections. The sealing element 4, on the other hand, comprises a support 6 for the entire accumulator element for the internal combustion engine and a fixture and seal of the tubular accumulator body of the accumulator element.

According to FIGS. 3 and 4 the control unit 5 can optionally be arranged in the pressure injector 2 (FIG. 4) or in the fuel injector 1 between the sealing element 4 and the associated fuel injector 1 (FIG. 4). 3).

The fuel supply device according to the invention is suitable for all types of large diesel engines, in particular internal combustion engines operated with heavy oil.

According to the invention, the accessibility to the control unit is significantly improved, in particular by the spatial separation of the control unit and the sealing element, while maintaining the advantage of pressure amplitude attenuation for the accumulator cover, in particular the functional unit of the 3 / 2-way valve and pressure tube. This makes it very easy to assemble / disassemble the control unit in the high pressure coupling state. In addition, in any case, the sealing element is not separated from the sealing surface of the associated high pressure accumulator unit when the control unit or the functional unit of the control unit is replaced, thereby minimizing the risk of leakage.

Claims (8)

A fuel supply device in the form of a common rail system for supplying fuel to a cylinder fuel injector of an internal combustion engine via a pressure tube, the pressure tube having at least one pressure accumulator chamber in a pressure accumulator unit at least whose end face can be closed by a sealing element. In the fuel supply device comprising: The sealing element is formed as an accumulator cover 3, and the accumulator cover consists of a module of the sealing element 4 and the control unit 5 in two parts, so that the sealing element 4 is sealingly coupled with the accumulator unit. In a fixed connection, the control unit 5 can be arbitrarily arranged between the sealing element 4 and the fuel injector 1 to be supplied in relation to the pressure tube 2, the control unit 5 being A fuel supply device characterized in that all functional units are integrated in connection with fuel supply and transport. 2. The pressure accumulator unit according to claim 1, wherein the pressure accumulator unit consists of a plurality of separate pressure accumulator chambers connected to each other by a transfer tube, wherein each pressure accumulator chamber has at least one fuel injector for the sealing element 4 and the control unit. Fuel supply device, characterized in that can be connected via the accumulator cover (3) consisting of (5). The pressure accumulator chamber (1) according to claim 2, wherein the pressure accumulator chamber has one accumulator volume each for supplying fuel to the two fuel injectors (1), the two end faces of the sealing element (4) and the control unit (5). A fuel supply device characterized in that it is configured to be closed by an accumulator cover (3) of two parts. The pressure control tube (5) according to any one of the preceding claims, wherein the control unit (5) of the accumulator cover (3) is connected to the cylinder head and between the sealing element (4) and the fuel injector (1). Fuel supply, characterized in that it is disposed immediately before said fuel injector (1) in relation to 2). 4. The control unit (5) according to any one of the preceding claims, wherein the control unit (5) of the accumulator cover (3) is arranged directly on the sealing element (4), and the pressure tube (2) is connected to the control unit (5). Fuel supply device, characterized in that it ends from the injector (1). Fuel supply according to one of the preceding claims, characterized in that the control unit (5) is arranged in the pressure tube (2) between the sealing element (4) and the fuel injector (1). Device. 4. Fuel supply according to one of the preceding claims, characterized in that the control unit (5) of the accumulator cover (3) is integrated in a fuel injector (1). 2. The spatial separation between the sealing element 4 and the control unit 5 is designed between 0 mm and 2000 mm, according to claim 1, wherein the diameter of the pressure tube 2 is about 7 mm. Fuel supply.

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