Turbine wastegate

1. An assembly comprising:

a turbine housing that comprises a bore, a wastegate seat, wastegate passages that extend to the wastegate seat and a divider wall disposed between the wastegate passages wherein the divider wall comprises a divider wall surface;

a rotatable wastegate shaft configured for receipt by the bore;

a wastegate arm extending from the wastegate shaft; and

a wastegate plug extending from the wastegate arm wherein the wastegate plug comprises a contact portion that contacts the wastegate seat to cover the wastegate passages in a closed state and wherein the wastegate plug comprises a mesh that contacts the divider wall surface in the closed state.

2. The assembly of claim 1 wherein the mesh is a wire mesh.

3. The assembly of claim 2 wherein the mesh comprises a nickel-chromium alloy.

4. The assembly of claim 1 wherein the wastegate plug comprises a recess wherein a portion of the mesh is disposed in the recess.

5. The assembly of claim 4 wherein the portion of the mesh disposed in the recess is greater than 50 percent of the mesh.

6. The assembly of claim 4 wherein the recess comprises an opening and wherein the mesh protrudes from the recess via the opening.

7. The assembly of claim 1 wherein the recess comprises an interior portion and an opening wherein the interior portion comprises a cross-wise dimension that exceeds a cross-wise dimension of the opening.

8. The assembly of claim 1 wherein the wastegate arm and the wastegate plug are a unitary piece.

9. The assembly of claim 8 wherein the mesh is a separate piece that is fit to the wastegate plug.

10. The assembly of claim 1 wherein the wastegate shaft, the wastegate arm and the wastegate plug are a unitary piece.

11. The assembly of claim 10 wherein the mesh is a separate piece that is fit to the wastegate plug.

12. The assembly of claim 1 wherein each of the wastegate passages comprises a corresponding opening defined in part by the divider wall.

13. The assembly of claim 1 wherein, in the closed state, the mesh reduces flow of exhaust from one of the wastegate passages to another of the wastegate passages.

14. The assembly of claim 13 operatively coupled to an internal combustion engine wherein the reduction in flow of exhaust increases torque of the internal combustion engine.

15. The assembly of claim 1 wherein the contact portion of the wastegate plug comprises a profile defined by a portion of a torus.

16. The assembly of claim 1 wherein the wastegate seat comprises a profile defined by a portion of a cone.

17. The assembly of claim 1 wherein, in an open state of the wastegate plug with respect to the wastegate seat, the mesh comprises a compressed interior portion disposed in a recess of the wastegate plug and an uncompressed exposed portion.

18. The assembly of claim 17 wherein, in the closed state, the exposed portion is compressed by contact with the divider wall surface.

19. The assembly of claim 18 wherein the compressed exposed portion of the closed state comprises a void space that is less than a void space of the uncompressed exposed portion of the open state.

20. A method comprising:

rotating a wastegate plug to cover wastegate passages separated by a divider wall that comprises a divider wall surface;

compressing a portion of a mesh attached to the wastegate plug via contact between the portion of the mesh and the divider wall surface; and

hindering flow of exhaust from one of the wastegate passages to another one of the wastegate passages via the compressed portion of the mesh.