A poppet valve includes: a valve body comprising a valve stem body, a valve head body with a valve combustion face, and a valve fillet body interconnecting the valve stem body and the valve head body. The valve fillet body surface has an increased thermal resistance compared to the valve combustion face.

A poppet valve includes: a valve body comprising a valve stem body, a valve head body with a valve combustion face, and a valve fillet body interconnecting the valve stem body and the valve head body. The valve fillet body surface has an increased thermal resistance compared to the valve combustion face.

A manufacturing method for a hollow engine valve comprises: a step of forming, by forging, a solid round bar as a material of a valve main body into a valve main body intermediate member provided with a semifinished product valve head portion corresponding to a valve head portion and a solid stem portion corresponding to a valve stem portion; a step of performing cutting process with respect to the valve main body intermediate member across the solid stem portion and the semifinished product valve head portion for forming a semifinished product hollow hole with a bottom corresponding to a hollow hole; and a step of performing necking process with respect to the valve main body semifinished product for squeezing the semifinished product valve stem portion step by step, to form the valve main body semifinished product into the valve main body.

A manufacturing method for a hollow engine valve comprises: a step of forming, by forging, a solid round bar as a material of a valve main body into a valve main body intermediate member provided with a semifinished product valve head portion corresponding to a valve head portion and a solid stem portion corresponding to a valve stem portion; a step of performing cutting process with respect to the valve main body intermediate member across the solid stem portion and the semifinished product valve head portion for forming a semifinished product hollow hole with a bottom corresponding to a hollow hole; and a step of performing necking process with respect to the valve main body semifinished product for squeezing the semifinished product valve stem portion step by step, to form the valve main body semifinished product into the valve main body.

An engine valve includes a stem, a head comprising an outer lip surface, a seating surface extending from the outer lip surface toward the stem, and a combustion surface extending from the outer lip surface on the opposite side of the head as compared to the seating surface. The combustion surface includes a first convex arcuate surface spaced away from the outer lip surface, at least partially forming a raised ring, and a first concave arcuate surface spaced away from the outer lip surface, at least partially forming a dimple.

A production method for a valve body of a hollow valve includes providing a preform with a valve head and a tubular wall which surrounds a cylindrical cavity. The tubular wall is flow formed above a flow forming mandrel which is inserted into the cavity in order to increase a length of the tubular wall. A hollow valve produced by flow forming is also disclosed.

A production method for a valve body of a hollow valve includes providing a preform with a valve head and a tubular wall which surrounds a cylindrical cavity. The tubular wall is flow formed above a flow forming mandrel which is inserted into the cavity in order to increase a length of the tubular wall. A hollow valve produced by flow forming is also disclosed.

The invention relates to a method for producing a valve body for a hollow valve. Said method comprises the following steps: providing a workpiece, blank or semi-finished product and a forming punch, introducing a protective layer between the workpiece and the forming punch (22) and press forming the workpiece to produce a preform. The invention also relates to a hollow valve produced by means of this method.

The invention relates to a method for producing a valve body for a hollow valve. Said method comprises the following steps: providing a workpiece, blank or semi-finished product and a forming punch, introducing a protective layer between the workpiece and the forming punch (22) and press forming the workpiece to produce a preform. The invention also relates to a hollow valve produced by means of this method.

A method for producing a valve body of a hollow valve includes providing a workpiece blank or semi-finished product, spin extruding the workpiece to produce a preform having a cup with a hollow shape formed by the cup wall. A hollow valve produced by this method is also provided.