DESCRIPTION The invention relates to a bearing housing of an exhaust-gas turbocharger as per the preamble of claim 1.

A fast supply of oil to the bearing arrangement of an exhaust-gas turbocharger is essential in particular during a cold start at low temperatures. Since the hot oil in the lines can drain out after the shutdown of the engine and under some circumstances the supply of oil takes too long during a cold start owing to high oil viscosity, damage to the bearing points can occur.

It is thus an object of the present invention to provide a bearing housing of the type specified in the preamble of claim 1, which bearing housing has an oil supply device which is of simple construction and which permits an adequate supply of oil to the bearing points of the bearing housing even during a cold start.

Said object is achieved by means of the features of claim 1.

According to the invention, the connecting region of the oil line is in the form of a siphon, which in the simplest case can be realized by means of a minor adaptation of the oil line running from the oil filter to the bearing housing of the exhaust-gas turbocharger. This is because the siphon may be formed as a type of kink in the oil line and collects the oil after the shutdown of the engine, which oil can then no longer flow out of the siphon.

The siphon is preferably arranged as close as possible to the inlet to the bearing housing. During a cold start, the oil is pumped to the bearing points by the pressure waves in the line as the engine is started. It is thus ensured in a simple manner that the bearing points of the bearing housing of the exhaust-gas turbocharger are supplied quickly and adequately with oil even in cold start phases.

The subclaims relate to advantageous refinements of the invention.

To avoid problems with oil carbon formation, in particular in the region of the siphon, in the post-heating phase, the oil supply line and also the siphon may be insulated. For this purpose, it is conceivable for the oil line or the siphon to be encapsulated or for heat shields to be provided in the region of the siphon and of the oil supply line.

To heat the oil which is highly viscous at low temperatures and thereby reduce the viscosity, the siphon may also be heated during the starting process. For this purpose, it is for example possible for a heating device to be integrated in the siphon or for a heating device in the form of a heating coil to be laid around the siphon. Further details, features and advantages of the invention will emerge from the following description of exemplary embodiments on the basis of the drawing, in which:

Figure 1 shows a schematically highly simplified illustration of an exhaust-gas turbocharger which can be provided with a bearing housing according to the invention,

Figure 2 shows a partial view of the bearing housing according to the invention as per a first embodiment, and

Figure 3 shows an illustration, corresponding to figure 2, of the bearing housing as per a second embodiment.

Figure 1 is a schematically highly simplified sketch of an exhaust-gas turbocharger 2 for the purpose of illustrating its basic components.

The exhaust-gas turbocharger 2 has a bearing housing 1 which connects a turbine housing 11 to a compressor housing 12. The exhaust-gas turbocharger 2 self-evidently also has all of the other conventional components, such as in particular a turbine wheel, a rotor shaft and a compressor wheel, but these are not discussed in detail because they are not necessary for explaining the principles of the present invention.

Figure 2 illustrates a part of the bearing housing 1 according to the invention likewise in schematically simplified form. The bearing housing 1 is provided with an oil inlet 3 to which a connecting region 4 of an oil supply line 5 is connected.

As shown in Figure 2, the connecting region 4 is in the form of a siphon 6 which is formed by a kink in the line, at which kink oil can collect after the shutdown of the engine without said oil flowing into the bearing housing 1, and said oil is thus in particular available for a cold start.

In the simplest case, to form the siphon 6, the oil supply line 5 is adapted or relocated accordingly. It is however alternatively also conceivable for the siphon 6 to be a separately producible component which is then connected at one end to an end region 13 of the oil supply line 5 and at another end region to a connecting piece 14 of the oil inlet 3.

In the embodiment illustrated in Figure 2, both the oil supply line 5 and also the siphon 6 are surrounded by an encapsulation 7 which prevents an excessive introduction of heat into the oil supply line 5 and the siphon 6.

Figure 3 is an illustration of the bearing housing 1 corresponding to Figure 2, but differs from the embodiment as per Figure 2 by the provision of a heating device 10 which, in the example, is in the form of a heating coil which is laid around the siphon 6, as can be seen in detail from Figure 3. Furthermore, in the example of Figure 3, two heat shields 8 and 9 are provided instead of the encapsulation 7, which heat shields prevent an excessive introduction of heat into the oil supply line 5 and the siphon 6. It would self-evidently also be possible in the embodiment as per Figure 2 for heat shields 8 and 9 of said type to be provided instead of the encapsulation 7.

As an alternative to a heating coil which is laid around the siphon 6 as in Figure 3, the heating device 10 could also be integrated in the siphon 6.

In addition to the above written disclosure of the invention, reference is hereby made explicitly to the diagrammatic illustration thereof in Figures 1 to 3.

LIST OF REFERENCE NUMERALS

1 Bearing housing

2 Exhaust-gas turbocharger 3 Oil inlet

4 Connecting region

5 Oil supply line

6 Siphon

7 Encapsulation

8, 9 Heat shields

10 Heating device

11 Turbine / Turbine housing

12 Compressor / Compressor housing

13 Connecting region

14 Connecting piece