TURBOCHARGERS

Abstract: A method of manufacturing a turbocharger comprising a housing having a compressor housing portion (10), turbine housing portion (11) and a connecting portion (12), the geometry of at least the connecting portion (12) being circular and concentric with respect to a common centre line passing through all three portions. The method of manufacture includes preselecting an appropriate attitude setting and then manufacturing the housing using a casting technique.

Description: TURBOCHARGERS The invention relates to turbochargers, and is particularly concerned with problems associated with what is known as attitude setting of turbochargers. A turbocharger basically comprises a compressor and a turbine coupled together, generally with a common shaft. Engine exhaust gases are fed into the turbine and rotate the turbine and the common shaft. This drives the compressor which is used to force air into the engine. The compressor has an inlet and an outlet, as does the turbine. On any given engine, there may be an optimum position for the location of the compressor inlet and/or outlet and an optimum position for the location of the turbine inlet and/or outlet. The compressor position may not necessarily have die same attitude with respect to the turbine position on different engines. It has therefore been necessary to provide means for clamping the compressor housing to the turbine housing in different positions so that the attitude of the compressor housing with respect to the turbine housing can be adjusted to suit any given engine. This not only necessitates the use of complicated clamping rings and associated seals, but a very sophisticated jig is necessary to hold and adjust the housings prior to clamping them together. A further problem associated with known turbochargers is that extensive milling and drilling is required to manufacture the housings. We have now developed a method of turbocharger manufacture which eliminates or substantially reduces the above-mentioned problems. According to the invention, a method of manufacturing a turbocharger comprises designing a turbocharger housing having a compressor housing portion, a turbine housing portion, and a connecting portion, the geometry of at least the connecting portion being circular and concentric with respect to a common centre line passing through all three portions, and then manufacturing the housing using a casting technique, the attitude of the compressor portion with respect to the turbine portion being preselected prior to casting by appropriate adjustment of the mould utilised in the casting process. There may for example be a compressor housing mould portion and a turbine housing mould portion, the two mould portions being rotatable with respect to one another about the said centre line before casting takes place. It is preferred that each inlet and outlet to the housing is circular, with an annular groove, so that connections to other components can be made using annular seals and clamping rings, such as those known as MARMAN fittings. Preferably the dimensions of each inlet and outlet are made substantially identical, so that a single size of clamping fitting can be used for connection to other components. The invention includes using the method of the invention to produce a series of different turbochargers having different attitude settings. The invention includes a turbocharger having a housing manufactured by the method according to the invention. There may be a series of different turbochargers having different attitude settings. The invention includes casting apparatus for use in carrying out the method according to the invention. The apparatus preferably has a compressor housing mould portion and a turbine housing mould portion, the two mould portions being rotatable with respect to one another. By way of example, specific embodiment of the invention will now be described, with reference to the accompanying drawings, in which: Figure 1 is a view of a first embodiment of turbocharger housing manufactured according to the invention, looking along the centre line of the housing; Figure 2 is a view looking in the direction of arrow II of Figure 1; Figure 3 is a view similar to Figure 1 but showing a second embodiment of turbocharger housing according to the invention; and Figure 4 is a view looking in the direction of arrow IV of Figure 3. Referring firstly to Figures 1 and 2, there is shown a turbocharger housing comprising a compressor portion 10, a turbine portion 11 , and a connecting portion 12. A common centre line 13 extends through the housing. The compressor portion has an inlet 14 and an outlet 15. The turbine portion has an inlet 16 and an outlet 17. The housing is manufactured from ductile iron using a casting process. It can be seen from Figure 1 that the axis 18 of the compressor outlet 15 is at 90° with respect to the axis 19 of the turbine inlet. Different engines may require different attitudes of the axis 18 with respect to the axis 19. The invention makes it possible to pre-select attitude setting before manufacture. Because the geometry of the connecting portion 12 of the housing is circular and concentric with respect to the axis 13, portions of the mould used in the casting process can be adjusted with respect to each other about the axis 13 to bring about any desired attitude setting. In Figure 3 and 4, for example, a second embodiment of housing is shown, which is substantially identical to that shown in Figures 1 and 2, similar reference numerals being used throughout. However it will be seen that the compressor outlet axis 18 now extends in the same direction as the turbine inlet attitude 19, instead of being at 90° to one another. Any attitude setting whatsoever can be selected. Because attitude setting is pre-selected during manufacture, no complicated attitude setting is necessary after manufacture and no special components are needed to clamp housing parts together. Customers receive exactly the attitude setting that they have requested and the desired attitude cannot subsequently get out of alignment. Manufacture of the housing takes place in a single process, and no milling or drilling is required. Turbocharger assembly time is substantially reduced. Because the housing is a single component, there is a risk of undesirable heat conduction from the turbine to the compressor, but this can be minimised by casting into the housing webs or fins such as those shown at 20 in Figures 2 and 4. Alternatively, air or water jackets may be provided, for example cast as an integral part of the turbine section, or the centre section, or both. A further advantage of the embodiments of housing shown in the drawings is that we have eliminated not only milling and drilling, but also the need for tapping. Conventional housings are generally connected at inlets and outlets by flanges which are bolted together. This necessitates drilling and tapping of bolt holes. In the embodiments shown, each inlet or outlet is circular, and has an annular groove 21. This makes it possible to make a connection to a similar- shaped component by using a clamping ring, and appropriate seals, the clamping ring for example having a U-shaped or V-shaped groove in its inner periphery, so that one wall of the clamping ring will seat in one of the grooves 21 and the other wall of the clamping ring will seat in a similar groove of the component to which the housing is connected. Fittings known as MARMAN fittings may for example be used. Yet another advantage is that each of the inlets and outlets, and associated annular grooves 21, are of the same size, so that only one size of clamping ring needs to be stocked to make all the necessary connections to the housing. The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims: CLAIMS 1. A method of manufacturing a turbocharger comprising designing a turbocharger housing having a compressor housing portion, a turbine housing portion, and a connecting portion, the geometry of at least the connection portion being circular and concentric with respect to a common centre line passing through all three portions, and then manufacturing the housing using a casting technique, the attitude of the compressor portion with respect to the turbine portion being preselected prior to casting by appropriate adjustment of the mould utilised in the casting process. 2. A method according to Claim 1 , utilising a compressor housing mould portion and a turbine housing mould portion, the two mould portions being rotatable with respect to one another about the said centre line before casting takes place. 3. A method according to either of Claims 1 or 2, in which each inlet and outlet to the housing is circular, with an annular groove, so that connections to other components can be made using annular seals and clamping rings. 4. A method according to any one of the preceding Claims, in which the dimensions of each inlet and outlet are made substantially identical, so that a single size of clamping fitting can be used for connection to other components. 5. A method according to any one of the preceding Claims, when used to produce a series of different turbochargers having different attitude settings. 6. A method of according to any one of the preceding Claims, in which any attitude setting whatsoever can be selected. 7. A method according to any one of the preceding Claims, in which the turbocharger housing is manufactured from ductile iron. 8. A method according to any one of the preceding Claims, in which undesirable heat conduction is minimised by casting webs or fins into the housing. 9. A method according to any one of the preceding Claims, in which undesirable heat conduction is minimised by providing air or water jackets. 10. A method according to Claim 9, in which the air or water jackets are cast as an integral part of the turbine housing portion. 11. A method according to Claim 9, in which the air or water jackets are cast as an integral part of the connecting portion. 12. A method of manufacturing a turbocharger substantially as hereinbefore described. 13. Casting apparatus for use in carrying out the method as claimed in any one of the preceding Claims. 14. Casting apparatus as claimed in Claim 13, having a compressor housing mould portion and a turbine housing mould portion, the two mould portions being rotatable with respect to one another. 15. Casting apparatus constructed and arranged substantially as hereinbefore described, with reference to the accompanying drawings. 16. A turbocharger having a housing manufactured by the method as claimed in any one of Claims 1 to 12, or by the apparatus as claimed in any one of Claims 13 to 15. 17. A plurality of turbochargers as claimed in Claim 16, each turbocharger having a different attitude setting.

Inventors: O'HARA STEPHEN JOHN, O'HARA, STEPHEN, JOHN
Applicants: HARA STEPHEN JOHN O, SCHWITZER EUROP LTD, O'HARA, STEPHEN, JOHN, SCHWITZER (EUROPE) LIMITED
Application year: 1995
Main classification: F01D25
IPC codes: B22C9, F01D25, F02B39