A poppet valve (2) with a valve body (4) has a cavity (6), a coolant inlet port (8). A coolant outlet port (10). The coolant inlet port (8) and the coolant outlet port (10) are arranged on a valve stem (12) of the poppet valve (2). The cavity (6) extends into the valve stem (12) of the poppet valve (2) and into a valve head (14) of the poppet valve (2), wherein there is provided a coolant conducting element (16) within the cavity (6) and extending into the cavity (6) from the valve head (14) to the valve stem (12), where the coolant conducting element (16) in each case has a cross-section. The coolant conducting element (16) includes a pipe section (18) and a funnel section (20), and the coolant conducting element (16) extends concentrically to the poppet valve (2) in the cavity (6) of the poppet valve (2).

A poppet valve (2) with a valve body (4) has a cavity (6), a coolant inlet port (8). A coolant outlet port (10). The coolant inlet port (8) and the coolant outlet port (10) are arranged on a valve stem (12) of the poppet valve (2). The cavity (6) extends into the valve stem (12) of the poppet valve (2) and into a valve head (14) of the poppet valve (2), wherein there is provided a coolant conducting element (16) within the cavity (6) and extending into the cavity (6) from the valve head (14) to the valve stem (12), where the coolant conducting element (16) in each case has a cross-section. The coolant conducting element (16) includes a pipe section (18) and a funnel section (20), and the coolant conducting element (16) extends concentrically to the poppet valve (2) in the cavity (6) of the poppet valve (2).

A method for manufacturing an engine poppet valve may comprise a forging operation, a diameter-decreasing operation, and a joining operation. At the forging operation, an intermediate member at which a valve head portion and an intermediate stem portion are made integral by way of a neck portion may be formed. At the diameter-decreasing operation, the intermediate stem portion may be inserted between/among a plurality of diameter-decreasing tools that have stem member compressing surfaces and stem member inlet surfaces formed so as to be progressively distant from the stem member compressing surfaces and toward the tip end and that are arranged at a plurality of circumferentially equipartite locations about a circumference of the intermediate stem portion, application at the intermediate stem portion from a base end portion of compressive forces which are inwardly directed in a radial direction from the compressing surfaces of the respective diameter-decreasing tools which have been made to come in contact with a part of the intermediate stem portion that has been made to rotate while being displaced in relative fashion in a direction along a central axis thereof causing the part of the intermediate stem portion to be decreased in diameter from the base end portion and causing a main body portion of a first stem portion to be formed at the intermediate member and also causing formation by the compressing surfaces of a stepped portion which is continuous with the main body portion, and formation, by an absence of decrease in diameter of a remaining portion at the intermediate stem portion, of a second stem portion which is broader in girth than the main body portion and which is continuous with the neck portion and which is also continuous with the main body portion by way of the stepped portion. At the joining operation, a stem end member having a same outside diameter as the main body portion may be joined to a base end portion of the main body portion.

A cooling system for a cylinder head of an internal combustion engine includes a cylindrical seat configured to engage an exhaust valve, a first coolant jacket, and a first conduit. The exhaust valve seat defines an annular cooling passage extending along a circumference of the cylindrical seat. A wall of the cylindrical seat defines a first opening into the annular cooling passage and a second opening into the annular cooling passage, where the first opening is positioned diametrically opposite to the second opening. The first coolant jacket is positioned adjacent to a fire-deck of the internal combustion engine. The first conduit fluidly couples the first coolant jacket to the at least one of the first opening and the second opening to the annular cooling passage in the exhaust valve seat.

A cooling system for a cylinder head of an internal combustion engine includes a cylindrical seat configured to engage an exhaust valve, a first coolant jacket, and a first conduit. The exhaust valve seat defines an annular cooling passage extending along a circumference of the cylindrical seat. A wall of the cylindrical seat defines a first opening into the annular cooling passage and a second opening into the annular cooling passage, where the first opening is positioned diametrically opposite to the second opening. The first coolant jacket is positioned adjacent to a fire-deck of the internal combustion engine. The first conduit fluidly couples the first coolant jacket to the at least one of the first opening and the second opening to the annular cooling passage in the exhaust valve seat.

An internally cooled valve (2) includes a valve body having a valve head (4) and a valve stem (6). The valve body has at least one cavity (8) in which coolant (10) is situated. The coolant is a nanofluid (12) in which nanoparticles (14) are dispersed in a dispersion medium (16).

An internally cooled valve (2) includes a valve body having a valve head (4) and a valve stem (6). The valve body has at least one cavity (8) in which coolant (10) is situated. The coolant is a nanofluid (12) in which nanoparticles (14) are dispersed in a dispersion medium (16).

An internal combustion engine may include at least one cylinder and at least one hollow-heat valve. The at least one hollow-head valve may include a valve shaft and a valve head, and may be guided in a valve shaft guide. The engine may also include at least one valve seat ring on which the valve head sealingly lies when the at least one hollow-head valve is closed. The engine may additionally include a valve shaft seal with at least two seal lips and oil disposed between the valve shaft and the valve shaft guide. The at least one valve seat ring may be composed of a sintered metal including infiltrated copper. The valve shaft may include one of a chromium-containing coating and a boron carbide-containing coating.

A cooling system for a cylinder head of an internal combustion engine includes a cylindrical seat configured to engage an exhaust valve, a first coolant jacket, and a first conduit. The exhaust valve seat defines an annular cooling passage extending along a circumference of the cylindrical seat. A wall of the cylindrical seat defines a first opening into the annular cooling passage and a second opening into the annular cooling passage, where the first opening is positioned diametrically opposite to the second opening. The first coolant jacket is positioned adjacent to a fire-deck of the internal combustion engine. The first conduit fluidly couples the first coolant jacket to the at least one of the first opening and the second opening to the annular cooling passage in the exhaust valve seat.

A cooling system for a cylinder head of an internal combustion engine includes a cylindrical seat configured to engage an exhaust valve, a first coolant jacket, and a first conduit. The exhaust valve seat defines an annular cooling passage extending along a circumference of the cylindrical seat. A wall of the cylindrical seat defines a first opening into the annular cooling passage and a second opening into the annular cooling passage, where the first opening is positioned diametrically opposite to the second opening. The first coolant jacket is positioned adjacent to a fire-deck of the internal combustion engine. The first conduit fluidly couples the first coolant jacket to the at least one of the first opening and the second opening to the annular cooling passage in the exhaust valve seat.