The invention relates to a cooled housing consisting of a turbine housing and a bearing housing for a turbocharger and a turbocharger with such a housing.
Turbochargers, as they are known from the prior art, generally have a turbine which is arranged in an exhaust gas stream. In operation, the turbine, driven by the exhaust gases from the engine, supplies the drive power for the compressor. The exhaust gas, which is here fed through an exhaust gas elbow into the turbine housing, drives the turbine wheel and this in turn a compressor wheel which is arranged on a shaft together with the turbine wheel. Here, the shaft is mounted on bearings in a bearing housing in the turbocharger. By the driving of the compressor via the turbine, the compressor raises the pressure in the engine's induction manifold, so that a larger quantity of air passes into the cylinder during the induction cycle. This means that more oxygen is available and a larger quantity of fuel can be burned.
As a consequence of the high temperatures of the exhaust gas stream which is fed through the turbocharger, the components of the turbocharger, in particular the turbine housing, are subject to a heavy thermal load. It is here possible, for example, that in an automobile internal combustion engine the exhaust gas can reach temperatures of up to 1100° C. In particular when operating under full load or close to full load, this can result in substantial temperature stresses on the components of the turbocharger.
Until now, the prior art has essentially relied on a suitable choice of materials for the manufacture of the housing parts for the turbocharger. Here, the selection of materials is made from the point of view of adequate strength at high temperatures. This involves the use of materials which are highly heat-resistant, which in general have high proportions of very expensive alloying elements, such as for example nickel. The effect of a high proportion of nickel in the material is that cast materials can better withstand the high temperatures. However, nickel has the disadvantage that it is a relatively expensive material. In the state of the art therefore, efforts are made to use alternative materials, or combinations of materials, which are more reasonable in price, but are equally suitable for high component temperatures and, in particular, do not require high proportions of expensive alloying elements, such as nickel.
Furthermore, a known approach in the prior art is to provide a cast-in cooling water jacket in the turbine housing, to lower the component temperature appropriately. However, such a jacket has the disadvantage that it is difficult to manufacture for small turbochargers, such as those used in vehicles, because an appropriate core must be provided for it.
Here, a turbocharger for marine use is known from DE 203 11 703. In this case the turbocharger has a cooled turbine-housing and bearing-housing. The turbine-housing is here constructed with a double wall, and is cooled by means of seawater. Further, the bearing housing has its own additional cooling facility, by which the bearing housing is cooled by means of a coolant from the coolant circuit of a connected engine, rather than by seawater as in the case of the turbine housing.
In addition, a turbine housing for a turbocharger is known from DE 100 22 052. In this case the turbine housing has, for example, a triple-walled construction. Here, the outer housing consists of several shells together with a welded-on water inlet and outlet. The outer and middle walls here form a hollow space, through which a coolant is fed. The inner and middle walls also form a hollow space, which forms an insulating air gap, whereby a sliding joint is also arranged in this hollow space to permit thermally-dependent length compensation between the sheet components. Here, a wire cushion stabilizes the sliding joint.
However, the turbine housing has the disadvantage that it has a complicated construction, due to its triple-walled design. The result of this is that the turbine housing is expensive to manufacture and assemble. Apart from this, only the turbine housing is provided with cooling, but not the bearing housing. The disadvantage of this is that the functionality of the turbocharger bearings can be degraded after hot soak conditions.
Accordingly, it is the objective of the present invention to provide a housing for a turbocharger with an improved cooling facility.
This objective is achieved by a housing with the characteristics of claim 1.
Accordingly the invention makes available for a turbocharger a housing, consisting of a turbine housing and a bearing housing, where the housing has a cooling jacket which is formed of at least one, or several, shell element(s) which are affixed to the housing externally and together with it form a hollow space into which a coolant can be fed.
This cooled housing, consisting of a turbine housing and a bearing housing, has the advantage that it is simple and cost-effective to manufacture, unlike the triple-walled turbine housing conforming to the prior art which must be welded together from three sheet layers. Furthermore, the additional cooling of the bearing housing makes it possible to maintain the functionality of the shaft bearing even after hot soak conditions.
Advantageous forms of embodiment and developments of the invention derive from the subclaims and from the description which makes reference to the drawings.
In accordance with one embodiment of the invention, the turbine housing and the bearing housing of the combined housing are constructed as one piece or two pieces. The one-piece form of embodiment has the advantage that a sealed joint of the turbine housing to the bearing housing to form one housing can be eliminated.
In a further form of embodiment in accordance with the invention, the turbine housing and/or the bearing housing has an appropriate seat on which to accommodate the other housing part. This seat can here take any required form, for example as a depression or a projection onto which the other housing part is pushed. By means of this seat, the two housing parts can be simply aligned and adjusted relative to each other before they are permanently joined to each other.
In another form of embodiment of the invention the shell element concerned can, for the purpose of affixing it to the housing and to form the cooling jacket, be a sheet component or a pressure diecasting, for example. A sheet component has the advantage of a constant thickness, whereby it can be reformed in order to form the appropriate contour for the cooling jacket. A pressure diecasting on the other hand needs no reforming but can also, for example, be designed with a more complex contour.
In accordance with another form of embodiment of the invention, the cooling jacket has on it, for example, at least one inlet connection for letting in a coolant and at least one outlet connection for letting out the coolant. The inlet and outlet connections can here be arranged adjacent to one another or on the same side of the housing, as appropriate. In this case, a separating wall element can optionally be arranged between the two connections. This has the advantage of preventing the fresh coolant which is fed into the cooling jacket from immediately flowing out again at the neighboring outlet before it has adequately flowed against the housing.
In another form of embodiment in accordance with the invention, the inlet and outlet connections are arranged some way apart from each other on the cooling jacket, for example on opposite sides. This has the advantage that no separating wall element is necessary between the two connections.
In a further form of embodiment in accordance with the invention, the shell element concerned can be attached to the housing by means, for example, of welding, soldering, bolting/screwing and/or gluing etc. The turbine housing and/or the bearing housing of the housing can as an option have appropriate attachment sections, to simplify the seating and attachment of the shell element concerned. The attachment section can here be of any desired design, for example in the form of a depression or a step, a groove or a slot etc., for suitably accommodating the shell element concerned. The attachment sections can here be in the same form or different.
In accordance with another inventive form of embodiment the coolant used is, for example, cooling water which is diverted off from an engine connected to the turbocharger in the housing. This has the advantage that a coolant circuit which is already present can be utilized.
In a further form of embodiment in accordance with the invention, the turbine housing, the bearing housing and/or the shell element concerned are at least partially or completely manufactured from plastic(s) and or fiber-bonded material(s). By this means the joint between the parts forms a suitable seal. Such plastics or fiber-bonded materials, as applicable, have the advantage that they are comparatively light, and thus the weight of the turbocharger can be reduced.
In another form of embodiment in accordance with the invention, the bearing housing has at least one or several feed lines in order to cool a part of, or essentially all of, the bearing arrangement which is mounted within the bearing housing. Through these feed lines, coolant is then fed into the region of the bearing arrangement and, as an option, the used or heated coolant is also fed off again through an appropriate feed line or return line, as applicable. This has the advantage that the coolant can be fed closer to the bearing arrangement, and it is possible thereby to achieve improved cooling.
The invention is explained below in more detail by reference to the exemplary embodiments shown in the schematic figures in the drawing. These show:
An example of a cooled turbocharger housing in accordance with the invention, consisting of a turbine-housing and bearing-housing, is explained below by reference to the figures. Such a turbocharger can be used, for example, in particular in an automobile or other vehicle.
The invention's approach is aimed, among other things, at the integration of the bearing housing and the turbine housing into one housing component or a casting, where the required cooling of the turbine housing material and of the bearing arrangement is effected by a cooling jacket. Here, the cooling jacket is formed of at least one, two, three or more shell element(s) attached around the combination housing consisting of the turbine-housing and bearing-housing, and thereby together with the housing forming a hollow space into which the coolant can be introduced.
The objective of the invention is a reduction in the component temperature for the turbine housing, in order to permit the use of cheaper materials. At the same time, the bearing housing should be integrated into the turbine housing and the cooling jacket extended to areas of the bearing housing which are to be cooled. By this means it is possible, for example, to maintain the functionality of the turbocharger bearings even after hot soak conditions.
The hollow space which is formed around the actual turbine-housing and bearing-housing part, in that at least one or several shell elements is/are attached to the housing, is then formed in such a way that it is suitable for a coolant to flow through it and can be extended over the bearing housing area by any required distance. For example, essentially over the entire bearing housing part, or over a section of the bearing housing.
The cooling jacket 18 in
If the housing 11, consisting of the turbine-housing and bearing-housing 10, 13 is made of an aluminum alloy, for example, then the shell element 14, 16 concerned can be made from a pressure diecasting which can, for example, be welded or soldered with the aluminum alloy. In this case, the pressure diecasting can, for example, have a wall thickness in the range of 2 mm to 3 mm or 2.5 mm to 3 mm, as appropriate, where the wall thickness of the pressure diecasting is not restricted to this range, but can also chosen to be less or greater, depending on its function and intended use.
Depending on whether there is an essentially liquid coolant or, for example, even a gaseous coolant in the cooling jacket 18, the shell element 14, 16 concerned will be attached to the turbine-housing and bearing-housing 10, 13 in a liquid-tight or gas-tight way, for example welded and/or soldered, in order to provide a suitable hollow space 12 for the coolant. However, it is also possible to provide other types of attachment and seals, which are suitable for joining the shell elements 14, 16 to the housing 11 in a liquid-tight or gas-tight way, as appropriate.
The turbine-housing and bearing-housing 10, 13, as shown in
In the present case, as shown in
As shown in
As shown in
As the coolant, which is fed into the cooling jacket 18 via the first connection 20, or the inlet connection, use can here be made of cooling water or some other suitable coolant. Furthermore, it is possible for example to use as the cooling water cooling water from the engine, or diverted off from it, as appropriate, or cooling water can be provided in a separate circuit.
As shown in
Here, the connections 20, 22 can be arranged at the same height as shown again, for example in the next
In an alternative form of embodiment, not illustrated, the inlet and outlet connections 20, 22 can also, for example, be arranged on the same side or directly alongside each other, or close to each other, where the two connections 20, 22 are in this case essentially separated from each other by, for example, a separating wall element (not illustrated). The separating wall element is in this case positioned in the cooling jacket 18 of the housing 11 in such a way that the coolant essentially flows via the inlet connection 20 initially into the cooling jacket 18 or its hollow space 12, and does not immediately flow away again through the neighboring outlet connection 22, but instead initially flows against the housing 11 or its turbine-housing and bearing-housing 10, 13, or at least flows partially or mostly around it, as applicable. When the coolant has mostly flowed around the turbine-housing and bearing-housing 10, 13, and has thereby for example absorbed heat from the hot or warm turbine-housing and bearing-housing 10, 13, it then flows out of the cooling jacket 18 again via the outlet connection 22. As previously described, the separating wall element serves the purpose of essentially preventing the fresh coolant from mixing with used or consumed coolant. In this case, the separating wall element can, for example, as appropriate be provided on or attached to the turbine-housing and bearing-housing 10 and/or an appropriate shell element 14, 16. The shell element can here be arranged and attached between the inlet and outlet connections 20, 22 in such a way that it separates them completely or at least partly from one another, in that the separating wall element is arranged, for example, between the two connections 20, 22 over the entire length of the housing 11, or at least over part of the length of the housing 11.
Further,
The attachment sections 24 on the turbine housing 10 are provided as appropriate, for example in the form of a depression 34 or a step in
As shown in
As an option, at least one, two or more additional flow elements 28 can be provided in the interior of the cooling jacket 18, for example to guide a liquid coolant. The two flow elements 28 can then each be constructed, for example, in the form of a rib which, for example, extends in an axial direction, as indicated in highly simplified form in
In addition, the inlet connection 20 is, for example, provided on the second shell element 16. In principle however, it would be possible for only one of the connections 20, 22 to be attacked to one of the shell elements 14, 16. The two connections 20, 22 are here, for example, attached separately to the shell element 14, 16 concerned, or formed into it, as applicable, and as shown in
For the purpose of cooling the bearing arrangement (not illustrated), arranged in the bearing housing 13, two infeed lines 38 are provided, for example, via which the coolant is fed into the region 40 of the bearing arrangement in order to cool it. In principle, the inventive cooling jacket 18 can be applied to any type of cooling of a bearing arrangement in a bearing housing 13 and to any type of infeed line 38 for the bearing arrangement coolant. The illustration in
In the present case, as it is shown in
The advantage of the inventive form of embodiment described above, in particular relative to a form of embodiment with a cast-in cooling jacket, is that the cooling jacket 18 can also be realized for very a small automobile turbine housing 10, because it does not require the use of core elements. Apart from this, it permits a reduction in the number of components in the turbocharger, the possible reduction to one coolant inflow and outflow for a cooled region of a turbine-housing and bearing-housing.
Although the present invention has been described above by reference to preferred exemplary embodiments, it is not restricted to them but can be modified in diverse ways. The forms of embodiment described above, in particular individual features of them, can here be combined with each other.
The coolant, such as for example cooling water for cooling the housing 11, can as already described be taken from a cooling circuit of an engine which is linked to the turbocharger. The cooling circuit here comprises, for example, an engine block, a thermostat, a radiator and a coolant pump. After cooling the housing 11, the coolant can be fed back to the cooling circuit. However, the invention is not restricted to this form of embodiment of a cooling circuit.
The provision of the cooling jacket 18 for cooling the housing 11 enables the latter to be made of less heat-resistant materials. For example, the housing 11 concerned can incorporate materials such as more lightly alloyed steels, aluminum, cast gray iron etc. By this means, it is possible to eliminate the use of expensive alloying elements such as for example nickel, or their proportions can at least be reduced. This has the further advantage that the manufacturing costs can be reduced.
Apart from this, it is possible to effect the engineering of the turbine housing 10, the bearing housing and/or the shell elements 14, 16 concerned not only in iron or non-ferrous metals, but also in plastic(s) and/or fiber-bonded material(s). In this case, the plastics or fiber-bonded materials, as applicable, are chosen such that they are suitable for the relevant temperatures which will arise in the turbine housing 10 or bearing housing 13 or shell elements 14, 16 constructed from them.
In this case, the turbine housing 10 or the bearing housing 13 and the shell elements 14, 16 concerned will be appropriately jointed, for example by means of welding, soldering, bolting/screwing with a seal between the shell elements 14, 16 concerned and the housing 11, and/or gluing, to name just some methods of attachment. The shell elements 14, 16 can each be manufactured from the same material or a different material, depending on their function and intended use. The same applies for the turbine housing 10 and the bearing housing 13.
Apart from the cooling function of the cooling jacket 18, by the introduction of the coolant, it is also possible for example to use the cooling jacket 18 for heating purposes, if for example the turbine housing 10 and bearing housing 13 should be warmed up or prewarmed to an operating state. In this case it is possible, for example, to use cooling water which has already been heated up by the engine, and introduce it into the cooling jacket 18.
Number | Date | Country | Kind |
---|---|---|---|
10 2008 011 258.5 | Feb 2008 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP08/64638 | 10/29/2008 | WO | 00 | 8/25/2010 |