Exhaust valve for an internal combustion engine, and a method of strengthening an annular valve seat area in an exhaust valve
AssigneeMan Diesel & Turbo, Filial Af Man Diesel & Turbo SE, Tyskland
InventorsHarro Andreas Hoeg, Christian Skaaning
Life of this patent
Estimating the term…
Abstract
An exhaust valve for an internal combustion engine comprises a valve disc having a first side (14) and a second side (16), a valve stem extending from the first side of the valve disc, and an annular valve seat area (11) located at the first side of the valve disc. The annular valve seat area (11) is of a nickel-base alloy or a chromium-base alloy and has a valve seat surface. The annular valve seat area has at least a first annular portion (43) located in between two second annular portions (42). The first annular portion has lower hardness than the two second annular portions.
Claims5
A method of strengthening an annular valve seat area in an exhaust valve for an internal combustion engine, which exhaust valve comprises a valve disc having a first side and a second side, a valve stem extending from the first side of the valve disc, and the annular valve seat area located at the first side of the valve disc, the annular valve seat area being a nickel-base alloy or a chromium-base alloy, wherein at least the following steps are performed:
- a) providing a valve disc with a raw seat area that has at least two annular protrusions separated by an intermediate annular area,
- b) plastically deforming the two annular protrusions,
- c) machining the raw seat area to the dimensions of the annular valve seat area, and
- d) heat treating the valve disc with the annular valve seat area with a heat treatment including at least an aging heat treatment.
Dependencies are inferred from the claim text.