Turbine for an exhaust gas turbocharger with a two-volute turbine housing and a valve arrangement having improved outflow

1. A turbine for an exhaust-gas turbocharger, the turbine comprising:

a turbine housing having two exhaust-gas volutes for a flow of exhaust gas, a separating wall between said two exhaust-gas volutes, and a common wastegate opening;

a linear valve having a valve element for selectively opening and closing said common wastegate opening, and a displacement shaft, with a shaft longitudinal axis, for actuating said valve element;

said displacement shaft extending through said separating wall in a direction of a separating wall plane spanned by said separating wall and movably disposed in a direction of said shaft longitudinal axis in said separating wall; and

said valve element being disposed in a separating wall cutout between said exhaust-gas volutes and being led out from a region of said exhaust-gas volutes, in a direction of the wastegate opening, toward a valve seat which is formed on an inner side of said wastegate opening facing towards said exhaust-gas volutes.

2. The turbine according to claim 1 , wherein said valve element has a valve disk which, in a closed state of said linear valve, lies sealingly against said valve seat, and a valve body on a side of said valve disk which is averted from said displacement shaft, said valve body projecting into said wastegate opening.

3. The turbine according to claim 2 , wherein said valve body, at least in one partial region, has an external geometry selected from the group consisting of conical, cylindrical, hemispherical and parabolic, which also defines an opening cross section of said wastegate opening when said linear valve is opening.

4. The turbine according to claim 2 , which comprises a volute valve slide disposed between said valve disk and said displacement shaft and fixed with said valve disk, and wherein said valve slide is received, adjustably in the direction of said shaft longitudinal axis, in a corresponding slide recess in said separating wall.

5. The turbine according to claim 4 , wherein said separating wall is formed, in the region of said valve slide, with a volute connecting window which is formed as an aperture through said separating wall and which is arranged in said separating wall to be closed by said volute valve slide when said linear valve is in the closed state.

6. The turbine according to claim 5 , wherein said volute valve slide is formed with a valve window being an aperture through said volute valve slide and wherein, with a progressive opening of said linear valve, said valve window progressively opens up said volute connecting window formed in said separating wall, to fluidically connect that said two exhaust-gas volutes to one another.

7. The turbine according to claim 1 , wherein said valve seat is formed by a valve seat ring installed in said wastegate opening.

8. The turbine according to claim 7 , wherein said valve seat ring is pressed into said turbine housing at said wastegate opening.

9. The turbine according to claim 1 , wherein said linear valve and said separating wall, arranged in the region of said linear valve, between said exhaust-gas volutes are constituent parts of a separate valve structural unit inserted into said turbine housing.

10. The turbine according to claim 9 , wherein said valve structural unit inserted into said turbine housing and is connected to said turbine housing by way of a connection selected from the group consisting of a screw connection, a welded connection, a press-fit connection, a caulked connection and a riveted connection.