An engine valve and a method of producing the engine valve are provided. The engine valve includes a shaft part and an umbrella part formed at one end of the shaft part. The engine valve opens and closes an intake port or an exhaust port of a combustion chamber of an internal combustion engine. Further, at least a portion of the engine valve that extends from the umbrella part to a position on the shaft part in a longitudinal direction thereof includes a valve body made of steel or nickel alloy, and a core member made of copper or copper alloy and provided inside the valve body.

A method for producing at least one hollow valve for gas exchange may include introducing a bore into a valve shaft and into a valve head to form the at least one hollow valve, measuring a depth of the bore, washing the at least one hollow valve at least once, providing the at least one hollow valve in a retaining device, orienting the retaining device together with the at least one hollow valve with respect to an associated electrode, moving the associated electrode in relation to the at least one hollow valve, inserting the associated electrode into the bore of the at least one hollow valve, enlarging the bore in a region of the valve head by electromechanical machining processes, removing the associated electrode from the at least one hollow valve, rinsing and/or preserving the at least one hollow valve, and measuring a wall thickness of a valve bottom.

Embodiments relate generally to energy storage systems, and in particular to energy storage systems using compressed gas as an energy storage medium. In various embodiments, a compressed gas storage system may include a plurality of stages to convert energy into compressed gas for storage, and then to recover that stored energy by gas expansion. In certain embodiments, a stage may comprise a reversible compressor/expander having a reciprocating piston. Pump designs for introducing liquid for heat exchange with the gas, are described. Gas flow valves featuring shroud and/or curtain portions, are also described.

A production method for a valve body of a hollow valve includes providing a preform with a valve head and a tubular wall which surrounds a cylindrical cavity. The tubular wall is flow formed above a flow forming mandrel which is inserted into the cavity in order to increase a length of the tubular wall. A hollow valve produced by flow forming is also disclosed.

A piston for an internal combustion engine includes a plurality of valve pockets formed in a piston rim, the valve pockets forming fluid flow paths through the piston rim. Each of the valve pockets includes a central step standing proud of a pocket floor to limit a fluid flow area through the pocket and slow combustion gas flow from a combustion bowl toward a cylinder liner and thereby reduce displacement of an engine oil film thereon.

A piston for an internal combustion engine includes a plurality of valve pockets formed in a piston rim, the valve pockets forming fluid flow paths through the piston rim. Each of the valve pockets includes a central step standing proud of a pocket floor to limit a fluid flow area through the pocket and slow combustion gas flow from a combustion bowl toward a cylinder liner and thereby reduce displacement of an engine oil film thereon.

A method for producing a valve body of a hollow valve includes providing a workpiece blank or semi-finished product, spin extruding the workpiece to produce a preform having a cup with a hollow shape formed by the cup wall. A hollow valve produced by this method is also provided.

A method for producing a valve body of a hollow valve includes providing a workpiece blank or semi-finished product, spin extruding the workpiece to produce a preform having a cup with a hollow shape formed by the cup wall. A hollow valve produced by this method is also provided.

A multi-valve for a cooling system of a motor vehicle includes: a valve housing, which has a plurality of inlets and a plurality of outlets and delimits a cylindrical valve chamber, the plurality of inlets and the plurality of outlets opening into the cylindrical valve chamber; and a valve unit, which is arranged inside the cylindrical valve chamber of the valve housing and is rotatable about an axis of rotation between a plurality of switching positions by an actuator. Depending on a switching position of the valve unit, different inlets of the plurality of inlets are fluidically connectable to different outlets of the plurality of outlets. The valve unit has a plurality of fluid channel structures which are offset from one another in a circumferential direction. Each switching position of the plurality of switching positions is respectively assigned a fluid channel structure of the plurality of fluid channel structures.

A multi-valve for a cooling system of a motor vehicle includes: a valve housing, which has a plurality of inlets and a plurality of outlets and delimits a cylindrical valve chamber, the plurality of inlets and the plurality of outlets opening into the cylindrical valve chamber; and a valve unit, which is arranged inside the cylindrical valve chamber of the valve housing and is rotatable about an axis of rotation between a plurality of switching positions by an actuator. Depending on a switching position of the valve unit, different inlets of the plurality of inlets are fluidically connectable to different outlets of the plurality of outlets. The valve unit has a plurality of fluid channel structures which are offset from one another in a circumferential direction. Each switching position of the plurality of switching positions is respectively assigned a fluid channel structure of the plurality of fluid channel structures.