A gas exchange valve for an internal combustion engine may include a valve stem and a wear resistance improving functional layer. The valve stem may extend in an axial direction and may transition into a valve plate in the axial direction. The functional layer may include nickel and tungsten. The functional layer may be arranged in a coating area on an outer circumference of the valve stem and may at least partially define a sliding surface.

A cylinder head valve seat of an automobile vehicle includes a valve seat having a valve seat surface integrally joined to an engagement end. The engagement end includes multiple materials extending through a cross section of the engagement end. The multiple materials include: a first material having a first thermal conductivity; and a second material having a second thermal conductivity higher than the thermal conductivity of the first material, wherein the first material transitions into the second material.

A method of manufacturing an engine valve intermediate product with a boss portion formed in integral fashion at an outer circumferential surface at an intermediate location on a stem forming portion. The manufacturing method may comprise a stem retaining operation in which an intermediate location of the stem forming portion is retained by a plurality of intermediate jigs removably installable radially with respect to a center of the stem forming portion, and a base end portion is retained by a base end jig. The manufacturing method may further comprise a stem enlarging operation in which compressive forces are applied from both ends of the intermediate product and the boss portion is formed as the intermediate product is made to rotate and alternating loads that cause tensile forces and compressive forces to act in repeated and alternating fashion at the outer circumferential surface of the stem forming portion are applied.

To find compromises in the relationship between the component costs of intake and exhaust valves and the downsizing of an engine and the relationship between the cooling performance and the followability of the intake and exhaust valves and coordinate these conflicting relationships as much as possible. A hollow valve encapsulating coolant having a good cooling function is used as an exhaust valve, which is exposed to a higher temperature environment than an the intake valve, to eliminate a disincentive to downsizing. In contrast, a hollow valve that has no coolant, relatively low component cost, light weight, and good followability is used as the intake valve, which does not need to have a better cooling function than the exhaust valve and needs to have better followability than the exhaust valve to improve combustion efficiency.

To find compromises in the relationship between the component costs of intake and exhaust valves and the downsizing of an engine and the relationship between the cooling performance and the followability of the intake and exhaust valves and coordinate these conflicting relationships as much as possible. A hollow valve encapsulating coolant having a good cooling function is used as an exhaust valve, which is exposed to a higher temperature environment than an the intake valve, to eliminate a disincentive to downsizing. In contrast, a hollow valve that has no coolant, relatively low component cost, light weight, and good followability is used as the intake valve, which does not need to have a better cooling function than the exhaust valve and needs to have better followability than the exhaust valve to improve combustion efficiency.

A rocker arm comprises a first outer arm and a second outer arm joined by a pivot body, the first outer arm comprising an inner side, the inner side comprising a limiting surface. An actuatable latch mechanism is within the pivot body. A first inner arm and a second inner arm are joined by a latch arm. An axle joins the first inner arm and the second inner arm to pivot between the first outer arm and the second outer arm. A second axle is between the first inner arm and the second inner arm. A pin extends from the second axle towards the first outer arm, and the pin is configured to pivot towards and away from the limiting surface when the first inner arm and the second inner arm pivot between the first outer arm and the second outer arm.

A rocker arm comprises a first outer arm and a second outer arm joined by a pivot body, the first outer arm comprising an inner side, the inner side comprising a limiting surface. An actuatable latch mechanism is within the pivot body. A first inner arm and a second inner arm are joined by a latch arm. An axle joins the first inner arm and the second inner arm to pivot between the first outer arm and the second outer arm. A second axle is between the first inner arm and the second inner arm. A pin extends from the second axle towards the first outer arm, and the pin is configured to pivot towards and away from the limiting surface when the first inner arm and the second inner arm pivot between the first outer arm and the second outer arm.

A method of manufacturing an engine valve intermediate product with a boss portion formed in integral fashion at an outer circumferential surface at an intermediate location on a stem forming portion. The manufacturing method may comprise a stem retaining operation in which an intermediate location of the stem forming portion is retained by a plurality of intermediate jigs removably installable radially with respect to a center of the stem forming portion, and a base end portion is retained by a base end jig. The manufacturing method may further comprise a stem enlarging operation in which compressive forces are applied from both ends of the intermediate product and the boss portion is formed as the intermediate product is made to rotate and alternating loads that cause tensile forces and compressive forces to act in repeated and alternating fashion at the outer circumferential surface of the stem forming portion are applied.

A control system for an internal combustion engine (ICE) is provided including a control unit configured for operating an electrically controlled valve for supplying compressed air to at least one cylinder depending on an operational mode for the ICE. A method for controlling such an ICE (200), and a computer are also provided.

Internal combustion engines having pistons with one or more depressions located on the piston head to facilitate the movement of air/charge in the cylinder are disclosed. The pistons may include a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The piston head also may be domed to further facilitate the movement of air/charge in the cylinder. The engines may also have non-circular, preferably rectangular, cross-section pistons and cylinders. The engines also may use multi-stage poppet valves in lieu of conventional poppet valves, and may include a split crankshaft. The engines may use the pumping motion of the engine piston to supercharge the cylinder with air/charge. The engines also may operate in an inverted orientation in which the piston is closer to the local gravitationally dominant terrestrial body's center of gravity at top dead center position than at bottom dead center position.