Patent ID: 8869511

Claim:
A large sized diesel engine, having a combustion room ( 3 ) delimited by a reciprocating piston ( 4 ), comprising: an exhaust valve ( 13 ) having a valve disc ( 15 ) arranged at a lower end of a valve shaft ( 14 ), the valve disc ( 15 ) including an underside which faces the combustion room ( 3 ) and being provided with a basin designed as a rotationally symmetric cavity ( 18 ) that is surroundingly bordered and downwardly open, wherein for retention of burnt gas, the maximum of rise of a concavely shaped underside of the valve disc ( 15 ) relative to an imaginary planar face ( 23 ) directly supporting the valve disc ( 15 ), is within the range of 2-10% of the outer diameter of the valve disc ( 15 ), at least one said tag being located with a line section of ¾ of the overall axial valve length opposed to the valve disc end, the tag of said exhaust valve being exposed for reading by non-contacting means positioned above the combustion room for said exhaust valve, and a combustion room volume formed by the cavity ( 18 ) on the underside of the valve disc ( 15 ) being compensated by raising a top face level of the piston ( 4 ) with a shims layer ( 24 ).