A method for introducing combustion air into a cylinder (25) of an internal combustion engine, a high-pressure inlet valve (1) provided therefor and an internal combustion engine that operates using the method and the high-pressure inlet valve are described. All the combustion air for the respective cylinders (25) is introduced into the cylinder (25) of the internal combustion engine, by means of a high-pressure inlet valve (1) arranged in the relevant cylinder head (26) and on the basis of a controlled mass flow, such that mixture formation and charge exchange are intensified. In addition, the temperature and/or pressure of the combustion air is measured and the quantity of combustion air is introduced into the cylinder (25), in a controlled manner and on the basis of the measurement results, by means of the high-pressure inlet valve (1) by opening or closing a sliding piston (3) of the high-pressure inlet valve (1) by displacement. As a result of an axial displacement of the sliding piston (3) between guide sections (5) in the housing (2) of the high-pressure inlet valve (1), passage areas (6) for combustion air are blocked in a closed position (7) and opened in an open position (8). In the passage area (6), the sliding piston (3) has two pressurization areas (10, 11) facing each other, the surfaces of which are of equal size or differ from each other when projected in one plane. The first pressurization area (10) can be designed as a poppet valve (12) and the second pressurization area (11) can be designed as an annular surface (13). The internal combustion engine has a high-pressure line (27) for the combustion air, which line is connected to the high-pressure inlet valve (1). With respect to the longitudinal axis of the cylinder (25), the high-pressure inlet valve (1) is arranged in the cylinder head (26) in an upright or horizontal position.

In a hollow exhaust poppet valve including a fillet increasing in diameter toward a leading end, a stem, and a head and having a coolant within a hollow part formed from the head to the stem, the stem includes a first stem part on a base end side, and a second stem part integrated with the first stem part via a step part and integrated with the fillet, and the hollow part includes a first hollow part formed inside the first stem part, and a second hollow part formed inside the second stem part, the fillet, and the head in such fashion as to have a constant inner diameter greater than the first hollow part and formed so as to be continuous with the first hollow part via a tapered part or a curved part.

In a hollow exhaust poppet valve including a fillet increasing in diameter toward a leading end, a stem, and a head and having a coolant within a hollow part formed from the head to the stem, the stem includes a first stem part on a base end side, and a second stem part integrated with the first stem part via a step part and integrated with the fillet, and the hollow part includes a first hollow part formed inside the first stem part, and a second hollow part formed inside the second stem part, the fillet, and the head in such fashion as to have a constant inner diameter greater than the first hollow part and formed so as to be continuous with the first hollow part via a tapered part or a curved part.

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 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.