DE102017205691A1 - Fuel high-pressure accumulator - Google Patents

Abstract

High-pressure fuel accumulator (16) for a fuel system (10) of an internal combustion engine has an elongated main body (26) with an elongated storage space arranged in the latter. It is proposed that the base body (26) is produced in an additive manufacturing process, in particular by a 3D printing process.

Description

State of the art

The invention relates to a fuel high pressure accumulator according to the preamble of claim 1.

The DE 199 49 963 A1 describes a method for producing a high pressure fuel accumulator for a common rail fuel injection system of an internal combustion engine. The high-pressure fuel accumulator comprises a hollow body and so far has a storage space, which is equipped with a plurality of connection openings. From the DE 199 49 963 A1 It is apparent that conventional high-pressure fuel accumulators are produced, for example, from a forging blank in which a longitudinal bore is formed, which forms the storage space. Fuel injector ports are also produced by drilling as well as, for example, by an electrochemical removal process.

Disclosure of the invention

Object of the present invention is to provide a high-pressure fuel storage, which is very compact.

This object is achieved by a high-pressure fuel storage with the features of claim 1. Advantageous developments of the invention are mentioned in subclaims. In addition, there are further features essential to the invention in the following description and in the drawing. These features may be essential for the invention, both alone and in different combinations, without being explicitly pointed out.

The fuel high-pressure accumulator according to the invention for a fuel system of an internal combustion engine has an elongated base body, in which an elongated storage space is arranged. According to the invention, it is proposed that the main body is produced in an additive manufacturing process, in particular by a 3D printing process. Additive manufacturing refers to a process in which a component is built up layer by layer on the basis of digital 3D design data by depositing material. Instead of, for example, milling a workpiece out of a solid block and then, for example, with a drill to edit, the additive manufacturing building components layer by layer of materials, which are usually present as a fine powder. As materials different metals, plastics and composites are available. First, for example, a thin layer of a powder material is applied to a build platform. A strong laser beam melts the powder exactly where the computer-generated part design data dictates. After that, the production platform lowers and another powder application takes place. The material is melted again and combines at the defined locations with the underlying layer. Depending on the source material and application, the components can be manufactured, for example, with stereolithography, laser sintering or 3D printers.

With such an additive manufacturing method, virtually any shape can be produced. As a result, an optimized in terms of the topology and shape construction of the high-pressure fuel storage is possible. The high-pressure fuel accumulator can thus be adapted particularly well to local space conditions in an engine compartment, for example of a motor vehicle, and to a required volume of the storage space.

Furthermore, connections for components, for example fuel injection devices, a pump, a pressure regulating valve, as well as a pressure sensor with regard to their position and position, taking into account individual requirements imposed by the space, for example, can be designed. Furthermore, by the manufacturing method proposed according to the invention, the range of materials from which the high-pressure fuel storage can be produced is extended. Both the material and the construction can be selected specifically with regard to the required nominal pressure and the function. Also, fuel high pressure accumulators with any number of ports for fuel injectors can be readily manufactured. Finally, in the so-called "intersection areas", in which terminals lead into the storage space, a design optimized in terms of strength can be realized.

In a first development, it is proposed that the storage space has a dimension in a longitudinal direction and dimensions in transverse directions, wherein the transverse directions extend substantially orthogonal to the longitudinal direction, and that the dimension changes seen in at least one transverse direction in the longitudinal direction. Thus, according to the invention, a storage space with a shape variable in the longitudinal direction is created. The shape of the storage space can be designed so voltage and / or flow optimized.

In a concrete further development, it is proposed that the storage space in a region of a connection has a larger cross-section than in a region remote from a connection Area. On the one hand, this is favorable for the course of the stresses in the main body and, on the other hand, for an optimal flow course in the storage space.

It is furthermore particularly advantageous if a longitudinal axis of the high-pressure fuel accumulator and / or a longitudinal axis of the storage space is wholly odd overall. This allows an arrangement of the fuel high pressure accumulator at a small distance, for example, to an engine block of an internal combustion engine, whereby space is saved.

In concrete development, it is proposed that the longitudinal axis has a waveform. This is easy to manufacture.

Another particularly advantageous embodiment of the invention provides that the fuel high-pressure accumulator has at least one holding section for holding a fuel injection device. Thus, it is possible to dispense with a separate mounting of the high-pressure fuel accumulator, for example on an engine block of an internal combustion engine. Overall, such a composite of high pressure fuel storage and directly held on this fuel injectors forms a very stable structure. If necessary, these can even be prefabricated, so that this prefabricated structure as a whole and thus can be mounted much faster on the internal combustion engine.

It is also particularly favorable if the high-pressure fuel accumulator is designed for the direct connection of at least one fuel injection device. Immediately means that a hitherto customary separate line between the fuel injection device and the high-pressure fuel storage can thus be omitted. This saves costs and eliminates points where leaks can occur. In essence, the fuel injector can be integrated into the design of the high-pressure fuel storage.

In a further development, it is proposed that at least one functional element, in particular a pressure regulating valve and / or a pressure sensor and / or a rod filter, is integrated in the basic body by means of additive production. It is possible, for example, that a complete assembly such as the pressure control valve, the pressure sensor or the rod filter are incorporated during the additive manufacturing process, for example as inserts. As a result, in turn, the assembly is simplified and it saves space. In particular, if, as mentioned above, the fuel injection device is directly connected to and held on the high pressure fuel reservoir, the rod filter can be very easily integrated into a connection channel between the storage space and the fuel injection device.

It is also possible that the storage space comprises at least one throttle point and / or honeycomb-like and / or sponge-like and / or grid-like structured. This is due to the fact that due to the conveying characteristic of conventional high-pressure pumps (this is usually sawtooth) and due to the injection processes by the fuel injectors to pressure fluctuations, in particular to pressure overshoots in the storage space can come. By integrating at least one throttle point into the storage space during the additive production of the high-pressure fuel accumulator, these pressure fluctuations can be reduced. In the same direction it goes if the storage space is at least partially honeycomb-like, sponge-like and / or grid-like structured. By the latter measures, the mentioned pressure overshoot can be reduced to a minimum without undesirably large throttle losses occur. It is also conceivable to provide a wall of the storage space at least in regions during the additive manufacturing process with a structured surface.

Finally, it is also part of the present invention that the high-pressure fuel accumulator comprises at least one fuel injector by being fixedly connected to it, wherein the fuel injector in an outer surface two straight parallel key surfaces for attaching a tool wrench and / or a claw having. Thus, an optionally required axial Pratzkraft can be applied to the fuel injection device very easily.

• 1 eine schematische Darstellung eines Common-Rail-Einspritzsystems mit einem Kraftstoff-Hochdruckspeicher und mehreren Kraftstoff-Einspritzvorrichtungen;
• 2 eine Seitenansicht auf den Kraftstoff-Hochdruckspeicher und die Kraftstoff-Einspritzvorrichtungen von 1;
• 3 eine Vorderansicht des Kraftstoff-Hochdruckspeichers und die Kraftstoff-Einspritzvorrichtungen von 1;
• 4 eine schematisierte Vorderansicht des Kraftstoff-Hochdruckspeichers ähnlich 3;
• 5 eine perspektivische Darstellung des Kraftstoff-Hochdruckspeichers und der Kraftstoff-Einspritzvorrichtungen von 1;
• 6 eine Ansicht von oben des Kraftstoff-Hochdruckspeichers von 1;
• 7 einen Längsschnitt durch den Kraftstoff-Hochdruckspeicher von 1;
• 8 eine Vorderansicht des Kraftstoff-Hochdruckspeichers von 1 ähnlich zu 3;
• 9 eine Seitenansicht des Kraftstoff-Hochdruckspeichers ähnlich zu 2;
• 10 eine perspektivische Darstellung des Kraftstoff-Hochdruckspeichers ähnlich zu 5;
• 11 eine Seitenansicht einer weiteren zweiten Ausführungsform eines Kraftstoff-Hochdruckspeichers;
• 12 eine perspektivische Darstellung des Kraftstoff-Hochdruckspeichers von 11;
• 13 eine perspektivische Darstellung eines Bereichs eines Kraftstoff-Hochdruckspeichers mit einer veränderten Ausführungsform einer Kraftstoff-Einspritzvorrichtung; und
• 14 eine Darstellung ähnlich zu 13, wobei zusätzlich eine Pratze dargestellt ist.

Hereinafter, embodiments of the invention will be explained with reference to the accompanying drawings. In the drawing show:

• 1 a schematic representation of a common rail injection system with a high-pressure fuel storage and a plurality of fuel injection devices;
• 2 a side view of the fuel high-pressure accumulator and the fuel injectors of 1 ;
• 3 a front view of the fuel high-pressure accumulator and the fuel injectors of 1 ;
• 4 a schematic front view of the high-pressure fuel storage similar 3 ;
• 5 a perspective view of the fuel high-pressure accumulator and the fuel injectors of 1 ;
• 6 a top view of the high-pressure fuel storage of 1 ;
• 7 a longitudinal section through the high-pressure fuel storage of 1 ;
• 8th a front view of the fuel high-pressure accumulator of 1 similar to 3 ;
• 9 a side view of the fuel high-pressure accumulator similar to 2 ;
• 10 a perspective view of the fuel high-pressure accumulator similar to 5 ;
• 11 a side view of another second embodiment of a high-pressure fuel storage;
• 12 a perspective view of the high pressure fuel storage of 11 ;
• 13 a perspective view of a portion of a high-pressure fuel storage with a modified embodiment of a fuel injection device; and
• 14 a representation similar to 13 , wherein additionally a claw is shown.

Elements and regions which have equivalent functions in different embodiments bear the same reference numerals below.

A common-rail injection system contributes in 1 Overall, the reference number 10 , It includes a fuel tank 12 , from which the fuel by means of a pumping device 14 , which usually includes an electrically driven feed pump and a mechanically driven high-pressure pump, in a high-pressure fuel storage 16 is pumped. At this are several fuel injectors 18 connected, of which in 1 however only one is drawn. At the high-pressure fuel storage 16 are also a pressure control valve 20 as well as a pressure sensor 22 arranged. To the common-rail injection system 10 also includes a control and regulating device 24 , which output side with the pumping device 14 and the fuel injectors 18 is connected, and which input side, inter alia, signals from the pressure sensor 22 receives. This is in 1 drawn by dashed lines.

The exact embodiment of a first embodiment of the high-pressure fuel storage 16 will now be with reference to the 2 - 10 explained.

The fuel high-pressure accumulator 16 includes an elongated body 26 in which a likewise elongated storage space 28 is available ( 4 and 7 ), in the operation of the common rail fuel system 10 the fuel is stored under very high pressure. The storage space 28 extends through the body 26 through from one end to the other, so as a through hole. The main body 26 is together with the storage space 28 in an additive manufacturing process, for example by a 3D printing process.

The main body 26 of the fuel high pressure accumulator shown in the figures 16 is for the supply of four fuel injectors 18 designed. In non-illustrated embodiments, however, any other numbers of fuel injectors are possible that can be powered by the high-pressure fuel storage. The main body 26 is with a total of four connection areas 30 executed. Between two adjacent connection areas 30 is in each case an intermediate area 32 available. The connection areas 30 have a larger outer diameter than the intermediate areas 32 , From the intermediate areas 32 to the connection areas 30 lead transition areas 34 which allows for a gradual change in the outer diameter of the intermediate areas 32 to the connection areas 30 to care.

Each connection area 30 has a lateral extension, which has a holding section 36 for holding a fuel injection device 18 forms. A holding section 36 is by a tangential to the main body 26 extending passage opening 38 ( 6 and 10 ), in which a fuel injector 18 can be inserted. Also the passage opening 38 has been produced as such in the context of the additive manufacturing process. To get an exact fit with the fuel injector 18 however, it is reworked by drilling. Defining the fuel injection device 18 in the passage opening 38 is a clamping screw 40 provided from the outside by a corresponding threaded hole 41 ( 9 and 10 ) in the holding section 36 is screwed, and in the installed position with its inner end an outer surface of the fuel injection device 18 charged (see also 4 ).

The direct fluidic connection between a fuel injector 18 and the storage space 28 is how out 4 can be seen through a short fluid channel 42 achieved, which is substantially orthogonal to a longitudinal direction 44 (for example 7 ) of the storage space 28 runs. In that regard, the fuel high-pressure accumulator 16 for direct connection of the respective fuel injectors 18 educated. In the fluid channel 42 is a functional element in the form of a rod filter 46 arranged, which at the additive Production in the holding section 36 of the basic body 26 was integrated.

At the in the 2 and 5 left end of the main body 26 is the pressure control valve 20 available. This can be screwed into a threaded bore produced by a post, through which it fluidly with the storage space 28 communicated. It is also possible that the pressure control valve 20 during the additive production of the main body 26 integrated in the form of an insert and so far integral with the body 26 is made. At the in the 2 and 5 right end of the main body 26 is the pressure sensor 22 available. Also with regard to the pressure sensor 22 that this is either screwed in or integral with the main body 26 can be made.

Like from the 7 and 8th indicates the memory space 28 one in the longitudinal direction 44 As far as variable cross section is concerned, than its dimension in a transverse direction 48 which are substantially orthogonal to the longitudinal direction 44 is, in the longitudinal direction 44 seen changed. In the area of the connection areas 30 In particular, it has a comparatively large cross-section 28a whereas in the area of transitional areas 34 and the intermediate areas 32 a comparatively small cross-section 28b having. Here is the storage space 28 in the area of the connection areas 30 concave from the inside (cross section 28a ), whereas in the area of intermediate areas 32 and the transition areas 34 seen from the inside is convex (cross section 28b ). The smallest cross section of the storage space 28 lies exactly in the middle between two adjacent connection areas 30 and is so small that thereby a throttle point 49 is formed for the fuel. Through such a throttle point 49 can pressure oscillations of the fuel in the storage space 28 be steamed. Not shown, but also possible is alternatively or in addition to the throttle 49 a honeycomb and / or sponge-like and / or lattice-like structuring of the storage space 28 ,

The second embodiment of the 11 and 12 is different from that of 2 - 10 in that the intermediate areas 32 and the transition areas 34 are formed differently. The to the connection areas 30 subsequent transition areas 34 namely have a curved longitudinal axis or longitudinal direction 44 on, so that between two transition areas 34 lying intermediate area 32 relative to the connection areas 30 axially offset laterally. Or, in other words: the longitudinal direction 44 of the high-pressure fuel storage 60 and with it the longitudinal direction 44 of the storage space 28 is non-rectilinear, namely odd or wavy.

Like from the 13 and 14 shows includes the high-pressure fuel storage 16 the fuel injectors 18 by doing this by means of the clamping screw 40 are firmly connected with him. In an outer surface 50 in the region of an upper end in the figures of the fuel injection devices 18 are two oppositely arranged, straight and parallel key surfaces 52 available ( 13 ). At these, for example, a claw 54 attach, by a required in particular for the assembly axial Pratzkraft on the fuel injection device 18 can be applied.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19949963 A1 [0002]

Claims (10)

High-pressure fuel accumulator (16) for a fuel system (10) of an internal combustion engine having an elongate base body (26) with an arranged therein elongated storage space (28), characterized in that the base body (26) in an additive manufacturing process, in particular by a 3D printing process is made. High-pressure fuel accumulator (16) after Claim 1 , characterized in that the storage space (28) has a dimension in a longitudinal direction (44) and dimensions in transverse directions (48), wherein the transverse directions (48) are substantially orthogonal to the longitudinal direction (44), and that the dimension in at least a transverse direction (48) in the longitudinal direction (44) changed. High-pressure fuel accumulator (16) after Claim 2 , characterized in that the storage space (28) has a larger cross-section in a region (30) of a connection than in a region remote from the region (30) of a connection. High-pressure fuel accumulator (16) according to one of the preceding claims, characterized in that a longitudinal axis (44) of the high-pressure fuel accumulator (16) and / or a longitudinal axis of the storage space is an odd overall. High-pressure fuel accumulator (16) after Claim 4 , characterized in that the longitudinal axis (44) has a waveform. High-pressure fuel accumulator (16) according to any one of the preceding claims, characterized in that it comprises at least one holding portion (36) for holding a fuel injection device (18). High-pressure fuel accumulator (10) according to any one of the preceding claims, characterized in that it is designed for direct connection of a fuel injection device (18). High-pressure fuel accumulator (16) according to any one of the preceding claims, characterized in that at least one functional element, in particular a pressure control valve (20) and / or a pressure sensor (22) and / or a rod filter (46), by means of the additive production in the main body (26) is integrated. High-pressure fuel accumulator (16) according to one of the preceding claims, characterized in that the storage space (28) comprises at least one throttle point (49) and / or honeycomb-like and / or sponge-like and / or lattice-like structured. High-pressure fuel accumulator (16) according to one of the preceding claims, characterized in that it comprises at least one fuel injection device (18) by being fixedly connected to it, wherein the fuel injection device (18) in an outer surface (50) at least has two straight parallel key surfaces (52) for applying a tool key and / or a claw (54).

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