A valve for use in an internal combustion engine is disclosed. The valve includes a stem friction welded to a head portion. The head portion is cast from a single crystal metal using a casting process that creates little or no grain boundaries. The single crystal metal can be a nickel based superalloys such as CMSX-4, CMSX 3, Rene N5, and Rene N6. By having little or no grain boundaries, defects that occur in other types of casting material, such as large numbers of grain boundaries can be minimized. This allows the head portion and particularly the combustion face to withstand an operating temperature in the combustion chamber in excess of 850 C.

An intake valve for a combustion engine is described. The intake valve has a head portion that is designed to improve the flow of air-fuel mixture around the head portion and into the combustion chamber. The head portion has a beveled or rounded edge at the top surface. The angle changes from the underside surface to the top surface are rounded to prevent separation of the air-fuel mixture from the surface of the intake valve. In addition, the underside surface of the head portion has a plurality of helical grooves that induce a circular flow to improve mixing of the air-fuel mixture in the chamber. The helical grooves also improve heat exchange between the air-fuel mixture and the intake valve.

A method for manufacturing a valve spindle having a valve disc and a valve stem, the method comprising the steps of: providing a capsule, which defines at least a portion of the valve disc; arranging, in the capsule, a preformed core body that includes a core head, which constitutes an inner portion of the valve disc; arranging a preformed annular valve seat in the capsule, wherein the valve seat is arranged such that the inner circumferential side of the valve seat at least partially defines an inner space around the core head; filling the inner space with a first metallic material, forming the buffer layer, such that the core head is covered with the first material; filling the capsule with a second metallic material, forming the cladding layer; subjecting the capsule to Hot Isostatic Pressing (HIP) at a predetermined temperature, a predetermined isostatic pressure and for a predetermined time so that the preformed core body, the buffer layer, the cladding layer and the valve seat are bonded metallurgically.

A gas exchange valve of an internal combustion engine may include a hollow valve stem and a valve disc. The valve disc may include a valve bottom and a hollow valve cone which is connected to an outer edge of said valve bottom. The hollow valve cone may taper with increasing distance from the valve bottom. The valve stem may pass through the hollow valve cone. The valve stem may be fixedly connected on the one hand to the valve bottom and on the other hand to the tapered end of the valve cone. The valve stem may include a first hollow space which is fluidically separated from a second hollow space arranged in the valve disc. The first hollow space and the second hollow space may have a different cooling agent filling level.

A gas exchange valve of an internal combustion engine may include a hollow valve stem and a valve disc. The valve disc may include a valve bottom and a hollow valve cone which is connected to an outer edge of said valve bottom. The hollow valve cone may taper with increasing distance from the valve bottom. The valve stem may pass through the hollow valve cone. The valve stem may be fixedly connected on the one hand to the valve bottom and on the other hand to the tapered end of the valve cone. The valve stem may include a first hollow space which is fluidically separated from a second hollow space arranged in the valve disc. The first hollow space and the second hollow space may have a different cooling agent filling level.

A valve actuation system is disclosed for use with an internal combustion engine. The valve actuation system may have a rocker shaft, a rocker arm pivotally mounted on the rocker shaft, at least one cam follower and a pushrod connecting the at least one cam follower to the rocker arm. The valve actuation system may also have a plurality of gas exchange valves, and a bridge connecting the rocker arm to the valves. The valve actuation system may further have at least one spring disposed around each of the valves and configured to bias each of the valves toward closed positions, and a rotocoil configured to rotatably connect the at least one spring to each of the valves. The rotocoil may have an internal chamfer at a bridge end with an angle of about 26-28. The at least one spring may have an assembled load of about 750-850 N.

A valve actuation system is disclosed for use with an internal combustion engine. The valve actuation system may have a rocker shaft, a rocker arm pivotally mounted on the rocker shaft, at least one cam follower and a pushrod connecting the at least one cam follower to the rocker arm. The valve actuation system may also have a plurality of gas exchange valves, and a bridge connecting the rocker arm to the valves. The valve actuation system may further have at least one spring disposed around each of the valves and configured to bias each of the valves toward closed positions, and a rotocoil configured to rotatably connect the at least one spring to each of the valves. The rotocoil may have an internal chamfer at a bridge end with an angle of about 26-28. The at least one spring may have an assembled load of about 750-850 N.

An improved apparatus for reducing friction in an EGR driver may include a space member mounted on a stem and having a side provided with a plurality of depressed portions to reduce a contact area with an inner side of a valve, such that the friction generated by a contact of the stem with a stem guide when the stem provided inside the valve vertically moves is reduced.

A method for manufacturing a metallic component including the steps of providing a capsule, which defines at least a portion of the shape of the metallic component, arranging metallic material in the capsule, sealing the capsule, subjecting the capsule to Hot Isostatic Pressing for a predetermined time, at a predetermined pressure and at a predetermined temperature, and optionally, removing the capsule. The metallic material is at least one pre-manufactured coherent body, which pre-manufactured coherent body being made of metallic powder, wherein at least a portion of the metallic powder is consolidated such that the metallic powder is held together into a pre-manufactured coherent body. At least one portion of the pre-manufactured coherent body is manufactured by Additive Manufacturing by subsequently arranging superimposed layers of metallic powder.

A film formation portion is formed on an annular edge portion along an opening portion (16a) of an intake port (16) or an opening portion (17a) of an exhaust port (17). The cross section, along the radial direction of the intake port (16) or the exhaust port (17), of the film formation portion, on which a metal film (5) is formed by spraying a raw material powder using a cold spray method, is formed in a groove shape that includes a flat bottom surface (G1) and a pair of side surfaces (G2) adjacent to the bottom surface.