The invention relates to a fuel feed device of the type described in the preamble of claim 1 and a method for producing such fuel feed device of the type described in the preamble of the claim 9.
EP 1 772 60 B1 discloses a generic device for attaching a high-pressure fuel accumulator to a cylinder head, with a high-pressure fuel accumulator, which has a main pipe extending along a longitudinal axis. The device also includes several fluid-tight passageways which are formed to extend completely through the aforementioned high-pressure fuel accumulator and extend substantially perpendicular to the longitudinal axis, as well as several screws which can be inserted through the respective several fluid-tight passageways. The fastening elements can here be mounted on the cylinder head, by which the high-pressure fuel accumulator is mounted on the cylinder head. The fluid-tight passageways are entirely formed by the aforementioned main pipe of the high-pressure fuel accumulator.
This device disadvantageously has an increased risk for leaks, which would allow fuel to leak from the high-pressure fuel accumulator, unless other measures are implemented.
It is therefore an object of the present invention to provide a fuel feed device and a method for producing such a fuel feed device with improved and more secure functional performance.
This object is achieved by a fuel feed device having the features of claim 1 and by a method for producing a fuel feed device having the features of claim 9.
An inventive fuel feed device for attachment to a cylinder head of an internal combustion engine having at least one fuel distribution element extending along a longitudinal direction and at least one connecting element extending transverse, in particular perpendicular, to the longitudinal direction, via which the fuel distribution element can be connected to the cylinder head, is characterized by at least one reinforcing element, which is connected, on one hand, to an outer surface of the fuel distribution element and, on the other hand, with the connecting element outside, in particular exclusively outside, the fuel distribution element.
With the reinforcing element, the connection between the fuel distribution element, which is also referred to as the fuel rail, and the connecting element is reinforced. As a result, the probability of an occurrence of a leak and thus a leakage of fuel received in the fuel distribution element is significantly reduced.
Because the reinforcing element is connected to an outer surface of the fuel distribution element, a particularly large connecting surface exists between the reinforcing element and the fuel distribution element. This leads to lower stresses in the connecting surface when the fuel in the fuel distribution element is under very high pressure. This is particularly advantageous when the reinforcing element is materially connected, in particular soldered, to the fuel distribution element and/or to the connecting element. Due to the available large connecting surface, the mechanical stress, for example in the weld seam, is low. The large connecting surface is under less stress even in the presence of a very high internal pressure in the fuel distribution element and biasing forces from injectors cooperating with the fuel feed device, which significantly reduces the probability of a failure, for example, of the weld seam, and thus destruction of the entire fuel feed device.
The aforementioned advantages can be attained without increasing a wall thickness of the fuel distribution element and thus also its weight. This keeps the total weight of the fuel feed device within a small range. The number of attachment points and connecting surfaces between the connecting element and the fuel distribution element can be kept low, which in turn leads to a low weight and low cost of the fuel feed device.
A connecting surface between the reinforcing element and the connecting element is particularly large, wherein low stresses, and thus also low loads in the connecting surface, exist due to the large connecting surface even at a high internal pressure in the fuel distribution element, even in the presence of mechanical bias forces due to attached injectors, as well as the fuel feed device connected to the cylinder head. Because the reinforcing element and the connecting member are soldered together, this reduces the load on the weld seam, which positively affects the functional performance and reliability of the fuel feed device.
Preferably, the reinforcing element is formed as a reinforcing plate which advantageously has a receptacle corresponding to an outer contour of the fuel distribution element in which the fuel distribution element is at least partially received, and which extends away from the fuel distribution element at an angle, in particular transversely, with respect to the longitudinal direction. The reinforcing element is thus shaped as a collar, by which the fuel feed device is reinforced in the connecting region between the fuel distribution element and the connecting element.
The functions of the fuel feed device are then safely met to a particularly high degree when the connecting element is materially connected to the fuel distribution element, in particular soldered.
A particularly strong and rigid connection with a long service life is realized in a particularly preferred embodiment of the invention, wherein a receiving space is formed between the reinforcing element and the connecting element and/or between the reinforcing element and the fuel distribution element, in which receiving space a connecting means, in particular a connecting means for materially connecting the reinforcing element to the connecting element and/or the reinforcing element to the fuel distribution element, such as solder, adhesive and/or the like, are received. In this case, a particularly large surface area for forming, for example, a solder joint, is available which significantly reduces stresses in the solder joint.
According to another embodiment, the reinforcing element may have at least one through-opening extending into the receiving space, through which the connecting means, such as the solder, may be introduced. In this way, liquid solder can also be introduced into the exception of the receiving space which is enclosed on all sides with the exception of the through-opening.
In a further advantageous embodiment, the fuel feed device includes two reinforcing elements, which are each connected, on one hand, to the outer surface of the fuel distribution element and, on the other hand, with the connecting element outside, in particular exclusively outside, the fuel distribution element. For example, the connecting element hereby passes through the fuel distribution element and protrudes by a certain distance from both sides of the connecting element in the axial direction, i.e., on both a top side and a bottom side. For example, one of the two connecting elements is now arranged on the top side of the fuel distribution element and connected, on one hand, to the outer surface of the fuel distribution element and, on the other hand, to the connecting element. The second of the reinforcing elements is then arranged at the bottom side and connected, on one hand, to the outer surface of the fuel distribution element and, on the other hand, to the connecting element. This provides a particularly strong connection between the connecting element and the fuel distribution element. In addition, the stresses in the corresponding connecting surfaces between the respective reinforcing elements and the connecting element and/or the fuel distribution element are very small, resulting in a long service life of the fuel feed device.
The invention also relates to a method of producing a fuel feed device for attachment on a cylinder head of an internal combustion engine having at least one fuel distribution element extending along a longitudinal direction and at least one connecting element extending transverse, in particular perpendicular, to the longitudinal direction, via which the fuel distribution element can be connected to the cylinder head, wherein in one step of the method, a receiving space is formed between an attachment piece and the fuel distribution element and/or the connecting element for a connecting means for connecting the attachment piece to the fuel distribution element and/or the connecting element. The connecting means can then be placed or introduced in this receiving space, producing a particularly large connecting surface between the attachment piece and the fuel distribution element and/or the connecting element. This also keeps the load on the connection surface, in particular in this tension, low, thereby providing a fuel feed device which has a high functional performance and reliability and therefore a long service life.
Further advantages, features and details of the invention will become apparent from the following description of a preferred exemplary embodiment and with reference to the drawings. The features and feature combinations mentioned above in the description and the features and feature combinations mentioned below in the description of the drawings and/or the features and feature combinations shown solely in the figures can be used not only in the respective described combination, but also in other combinations or in isolation, without deviating from the scope of the invention.
The drawings show in:
As seen clearly in the context of
The high-pressure fuel reservoir 10 further includes reinforcing plates 30, wherein the respective reinforcing plate 30 is soldered, on one hand, to the outer surface 26 and, on the other hand, to the sleeve 24 exclusively on the outside of the fuel distribution pipe 12.
Moreover, a receiving space 32, in which the solder for soldering is received, is formed between the reinforcing plate 30 and the sleeve 24 and the fuel distribution pipe 12. In this way, soldering surfaces 34 are available for soldering the reinforcing plate 30 to the fuel distribution pipe 12 and the sleeve 24, ensuring a particularly strong connection of the fuel distribution pipe 12 with the sleeve 24. Moreover, the sleeve 24 is connected with solder applied to additional soldering surfaces 36 with the fuel distribution pipe 12, with solder applied at soldering surfaces 38 with the sleeve 22. The sleeve 22 is connected, via solder applied to corresponding solder surfaces 40, with fuel distribution pipe 12.
The reinforcing plate 30 provides very large solder surfaces 34, which in particular greatly relieves a solder seam between the fuel distribution pipe 12 and the sleeve 22, thereby lowering the probability for crack formation and formation of leaks in the high-pressure fuel accumulator 10.
When the fuel distribution pipe 12 has a high internal pressure and when the high-pressure fuel accumulator 10 is screwed to the cylinder head with bolts passing through the sleeves 22 and 24, the stresses and thus loads remain low in the solder surfaces 34, 36, 38 and 40, resulting in a very low risk for cracking. Since the reinforcing plate 30 is connected to the outer surface 26 and extends in the axial direction away from the fuel distribution pipe 12, the size especially of the soldering surface 34 does not depend on the wall thickness of the fuel distribution pipe 12, as is the case, for example, with the soldering surface 40. This produces a rigid connection between the fuel distribution pipe 12 and the sleeves 22 and 24, without increasing the weight of the fuel distribution pipe 12.
For arranging solder in the receiving space 32, the reinforcing plate 30 has at least one through opening 46 (
In other words, the high-pressure fuel accumulator 10 is produced by first plugging the sleeves 22 and 24 and the reinforcing plate 30 together, whereby the seal 28 and any solid solder rings are also mounted. The pre-assembled high-continuous pressure fuel accumulator 10 is then transported into and conveyed through the furnace for forming the respective solder joint. Thereafter, in a final assembly of the gasoline or diesel engine, the high-pressure fuel accumulator 10 is attached to the cylinder head, whereby the screws are guided through the sleeves 22 and 24 and screwed into the cylinder head.
Instead of the two sleeves 22 and 24 shown in the figures, only the sleeve 22 may be provided, whereby the seal 28 and a corresponding solder joint between the sleeve 22 and 24 is omitted. In this case, the connecting plate 30 is soldered, on one hand, to the outer surface 26 of the fuel distribution pipe 12 and, on the other hand, to the sleeve 22. The stresses on the corresponding solder surfaces during operation are also low in this embodiment of the high-pressure fuel accumulator 10, which results in a highly functional and reliable performance of the high-pressure fuel accumulator 10 and a very low probability for the occurrence of leaks.
Moreover, an additional reinforcing plate 31 is arranged on the top side 42, which like the reinforcing plate 30 is soldered, on one hand, to the outer surface 26 of the fuel distribution pipe 12 and, on the other hand, to the sleeve 24 exclusively outside of the fuel distribution pipe 12. A respective receiving space 32, in which the solder for soldering is received, is formed once more between the reinforcing plates 30 and 31 and the sleeve 24 and the fuel distribution pipe 12. In analogy to the reinforcing plate 30, the reinforcing plate 31 also has solder surfaces 34 for soldering the reinforcing plate 30 to the fuel distribution pipe 12 and the sleeve 24 in order to provide a particularly strong connection. The sleeve 24 is also soldered to the fuel distribution pipe 12 with solder applied to other solder surfaces 40. By providing two reinforcing plates 30 and 31 on both the top side 42 and on the bottom side 44, the solder surfaces 34 and 40 are subjected to very low loads and stresses during the operation of the gasoline or diesel engine, resulting in a long service life of the high-pressure fuel accumulator 10.
Number | Date | Country | Kind |
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10 2010 018 615.5 | Apr 2010 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2011/002110 | 4/27/2011 | WO | 00 | 10/24/2012 |