A scavenger valve and method of directing gas in a two stroke engine are provided involving poppet elements in a scavenger valve with specific multiple, different flow paths from individual poppet heads.

A valve seat ring for a gas exchange valve of a cylinder of an internal combustion engine includes: a one-part or multi-part main body defining a through-flow opening; and a valve seat region arranged on a portion of the main body in the region of the through-flow opening, a surface of the valve seat region forming a valve seat for a valve body of the gas exchange valve. At least into the main body at least one recess is introduced, which is at least partly filled with a solder material.

A valve seat ring for a gas exchange valve of a cylinder of an internal combustion engine includes: a one-part or multi-part main body defining a through-flow opening; and a valve seat region arranged on a portion of the main body in the region of the through-flow opening, a surface of the valve seat region forming a valve seat for a valve body of the gas exchange valve. At least into the main body at least one recess is introduced, which is at least partly filled with a solder material.

A piston for an internal combustion engine includes a plurality of valve pockets formed in a piston rim, the valve pockets forming fluid flow paths through the piston rim. Each of the valve pockets includes a central step standing proud of a pocket floor to limit a fluid flow area through the pocket and slow combustion gas flow from a combustion bowl toward a cylinder liner and thereby reduce displacement of an engine oil film thereon.

A piston for an internal combustion engine includes a plurality of valve pockets formed in a piston rim, the valve pockets forming fluid flow paths through the piston rim. Each of the valve pockets includes a central step standing proud of a pocket floor to limit a fluid flow area through the pocket and slow combustion gas flow from a combustion bowl toward a cylinder liner and thereby reduce displacement of an engine oil film thereon.

A cylinder head having a cast-in-place valve seat for an automobile vehicle includes a valve seat having an inner wall. At least one retaining feature integrally and homogeneously extends from the inner wall. The valve seat when positioned into a casting mold has the at least one retaining feature assisting in retaining the valve seat in the casting mold. A metal in a molten form is received in the casting mold. A cast component formed after cooling of the metal has the valve seat cast-in-place.

A cylinder head having a cast-in-place valve seat for an automobile vehicle includes a valve seat having an inner wall. At least one retaining feature integrally and homogeneously extends from the inner wall. The valve seat when positioned into a casting mold has the at least one retaining feature assisting in retaining the valve seat in the casting mold. A metal in a molten form is received in the casting mold. A cast component formed after cooling of the metal has the valve seat cast-in-place.

A method for manufacturing a poppet valve or mushroom valve includes providing a mixture of metal powder and a binder, filling and pressing said mixture in a mold, to obtain a green product, removing the binder from the green product, and thermally sintering the green product to a poppet valve blank, by hot isostatic pressing. A poppet valve is also provided that is manufactured with this method.

An engine head assembly includes a valve seat insert having a valve seating surface defining a center axis, and each of an inner peripheral surface and an outer peripheral surface extending circumferentially around the valve seat center axis. The outer peripheral surface includes an upper section interference-fitted with the engine head, and a lower section. A stiffness relief channel is formed by a relief cutout in the valve seat insert, and extends radially between the lower section of the outer peripheral surface and the engine head. The stiffness relief channel permits flexing of the valve seat insert to cushion valve seating to prolong engine valve and valve seat insert service life.

An engine head assembly includes a valve seat insert having a valve seating surface defining a center axis, and each of an inner peripheral surface and an outer peripheral surface extending circumferentially around the valve seat center axis. The outer peripheral surface includes an upper section interference-fitted with the engine head, and a lower section. A stiffness relief channel is formed by a relief cutout in the valve seat insert, and extends radially between the lower section of the outer peripheral surface and the engine head. The stiffness relief channel permits flexing of the valve seat insert to cushion valve seating to prolong engine valve and valve seat insert service life.