A method without a calibration step produces a camshaft adjuster including a stator, a rotor rotatable relative thereto and a control valve, wherein the rotor and/or the stator is or are produced according to a powder-metallurgical process, wherein the stator in the region of a fitting surface for contacting the camshaft and/or the rotor in the region of a fitting surface for contacting the camshaft and/or in the region of a fitting surface for contacting the control valve and/or the control valve in the region of a sealing surface is or are produced having a tolerance so that a clearance fit with a maximum clearance of 100 μm is formed between the fitting surface for the camshaft and the camshaft and/or between the fitting surface for contacting the sealing surface of the control valve and the sealing surface of the control valve.

A valve assembly that can be employed in a variable camshaft timing (VCT) phaser assembly. The valve assembly includes a metal sleeve and a check valve. The check valve, in an implementation, has an integral construction with the metal sleeve. The integral construction has multiple designs, one of which includes an overmolded construction of the check valve with the metal sleeve. The valve assembly can also include a valve housing which, in the implementation of the VCT phaser assembly, is a center bolt.

A control valve for a cam phaser of an internal combustion engine, the control valve including a cylindrical housing, including a first operating connection, a second operating connection, a supply connection, and a tank drain connection configured to drain a hydraulic fluid; a control piston device, including a control piston, a supply tube, a first check valve and a second check valve enabling cam torque recirculation, wherein the control piston device is arranged in the housing and axially movable by an actuator, wherein the first check valve is configured with a first disc portion and a second disc portion and the second check valve is configured with a third disc portion and a fourth disc portion and the first check valves and the second check valve are arranged offset from each other by a compression coil spring.

A central valve for a camshaft phaser includes a hollow cylindrical housing, a hydraulic unit, a control piston, a retaining ring, and a washer. The hollow cylindrical housing includes a first radial opening and a groove. The hydraulic unit is disposed in the hollow cylindrical housing and includes a second radial opening and a channel. The control piston is axially moveable in the hydraulic unit to adjust a flow of a hydraulic medium through the first radial opening, the second radial opening, and the channel. The retaining ring is disposed in the groove to retain the hydraulic unit and the control piston in the hollow cylindrical housing. The washer is disposed in the hollow cylindrical housing axially between the hydraulic unit and the retaining ring.

Raw material powder containing iron powder, copper powder, and tin powder is compressed to form a green compact. The green compact is sintered in a temperature range of from 750 to 900° C., to bond iron structures to each other with copper and tin.

A poppet valve includes: a valve body comprising a valve stem body, a valve head body with a valve combustion face, and a valve fillet body interconnecting the valve stem body and the valve head body. The valve fillet body surface has an increased thermal resistance compared to the valve combustion face.

An actuator control system suitable for providing single wire control of electromagnetic latch assemblies providing for cylinder deactivation or variable valve actuation in a valvetrain system. The system is adapted to control electromagnetic latch assemblies that require DC current in a first direction for latching and DC current in a reverse of the first direction for unlatching. The actuator control system includes an inverting DC/DC converter and switching elements. In some embodiments, the inverting DC/DC converter uses capacitors to store energy that drives the inverted current. In some embodiments, the inverting DC/DC converter serves a plurality of distinct groups of the electromagnets.

A method for producing a valve body of a hollow valve with optimised interior stem geometry includes a preform with a valve plate and a tubular wall surrounding a cavity. Flow forming the tubular wall over a flow-forming mandrel, which is inserted into the cavity to enlarge a length of the tubular wall. An interior area of the tubular wall is embossed with a structure either due to the fact that the flow-forming mandrel is a structuring mandrel having a surface structure, or alternatively, because the method includes a further step of reducing an outer diameter of the tubular wall by swaging or drawing and ironing over a structuring mandrel. Furthermore, a hollow valve is produced by this method.

A summation rocker system is disclosed for acting on the end of a stem of a poppet valve (16) in dependence upon the combined lifts of a first and a second cam profile defined by different cam lobes (14, 22) of a concentric camshaft (46). The system comprises a first rocker (12) mounted on a pivot shaft (18) and having a first follower (44) to contact the first cam profile and an end acting on the valve (16) to displace the valve (16) by an amount dependent upon the lift of the first cam profile, a rocker shaft (24) to be fixedly mounted on the engine, and a second rocker (20) pivotable about the rocker shaft (24), the second rocker (20) having a second follower (48) to contact the second cam profile and acting to displace the pivot shaft (18) of the first rocker (12) in dependence of the lift of second cam profile. The rocker shaft (24) intersects a plane containing the axis of the pivot shaft (18) and the end of the first rocker (12) acting on the valve stem, and the first rocker (12) includes a cut-out (26) for receiving the rocker shaft (24), which cut-out (26) is configured and dimensioned to prevent the rocker shaft (24) from interfering with movement of the first rocker (12).

A check valve is made of a resilient body wound in a ring form and is located in an annular flow passage. A displacement limiter includes: a limiter main body that is located on an outer side of the check valve and is configured to limit displacement of the check valve in a diameter increasing direction of the check valve; and a limiter flow passage that communicates between one side and the other side of the limiter main body in an axial direction to enable hydraulic oil to flow between the one side and the other side of the limiter main body through the limiter flow passage.