A valve seat insert includes a top convex arcuate blend for improving fluid flow, and a valve seating surface for slowing down valve recession. The valve seating surface includes a radially outer convex arcuate segment defining an outer radius of curvature forming a first wear crown for contacting the valve at an early wear state, a radially inner convex arcuate segment defining an inner radius of curvature forming a second wear crown for contacting the valve at a later wear state, and a linear segment extending between the radially outer convex arcuate segment and the radially inner convex arcuate segment.

A method for the production for a semi-finished valve product (4), includes casting, forging, deep-drawing, pressing and/or drop-welding of one or several metal material into a semi-finished valve product (4) that corresponds to a circle segment of a valve cut open in the axial direction. A valve is produced by welding together at least two semi-finished valve products (4) into an internally cooled valve, with the weld running in the axial direction of the valve.

A method for the production for a semi-finished valve product (4), includes casting, forging, deep-drawing, pressing and/or drop-welding of one or several metal material into a semi-finished valve product (4) that corresponds to a circle segment of a valve cut open in the axial direction. A valve is produced by welding together at least two semi-finished valve products (4) into an internally cooled valve, with the weld running in the axial direction of the valve.

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 valve seat insert includes a top convex arcuate blend for improving fluid flow, and a valve seating surface for slowing down valve recession. The valve seating surface includes a radially outer convex arcuate segment defining an outer radius of curvature forming a first wear crown for contacting the valve at an early wear state, a radially inner convex arcuate segment defining an inner radius of curvature forming a second wear crown for contacting the valve at a later wear state, and a linear segment extending between the radially outer convex arcuate segment and the radially inner convex arcuate segment.

A valve seat insert includes a top convex arcuate blend for improving fluid flow, and a valve seating surface for slowing down valve recession. The valve seating surface includes a radially outer convex arcuate segment defining an outer radius of curvature forming a first wear crown for contacting the valve at an early wear state, a radially inner convex arcuate segment defining an inner radius of curvature forming a second wear crown for contacting the valve at a later wear state, and a linear segment extending between the radially outer convex arcuate segment and the radially inner convex arcuate segment.

A valve seat insert includes a top convex arcuate blend for improving fluid flow, and a valve seating surface for slowing down valve recession. The valve seating surface includes a radially outer convex arcuate segment defining an outer radius of curvature forming a first wear crown for contacting the valve at an early wear state, a radially inner convex arcuate segment defining an inner radius of curvature forming a second wear crown for contacting the valve at a later wear state, and a linear segment extending between the radially outer convex arcuate segment and the radially inner convex arcuate segment.

A valve seat insert includes a top convex arcuate blend for improving fluid flow, and a valve seating surface for slowing down valve recession. The valve seating surface includes a radially outer convex arcuate segment defining an outer radius of curvature forming a first wear crown for contacting the valve at an early wear state, a radially inner convex arcuate segment defining an inner radius of curvature forming a second wear crown for contacting the valve at a later wear state, and a linear segment extending between the radially outer convex arcuate segment and the radially inner convex arcuate segment.

A method of operating an internal combustion engine having an electrical circuit that includes a connection closed by abutment between two distinct parts, one of which is mounted to a rocker arm of a rocker arm assembly and another that is mounted to a part distinct from the rocker arm. The connection is structured such that the movement of the rocker arm causes relative motion between the surfaces of the distinct parts that close the connection. The relative motion causes the circuit resistance to transition between values within a first range and values within a second range. The transitions of resistance between those ranges are detected and their presence, absence, or timing used for purposes of providing diagnostic feedback or control.

A method of operating an internal combustion engine having an electrical circuit that includes a connection closed by abutment between two distinct parts, one of which is mounted to a rocker arm of a rocker arm assembly and another that is mounted to a part distinct from the rocker arm. The connection is structured such that the movement of the rocker arm causes relative motion between the surfaces of the distinct parts that close the connection. The relative motion causes the circuit resistance to transition between values within a first range and values within a second range. The transitions of resistance between those ranges are detected and their presence, absence, or timing used for purposes of providing diagnostic feedback or control.