US Patent 9784143 Mid lock directional supply and cam torsional recirculation

A valve timing control device, in effect a cam phaser, for an internal combustion engine. The valve timing control device includes a rotor connected to a camshaft and having a plurality of vanes. A stator is engaged with the rotor, and includes a plurality of webs. Pressure chambers are provided between each of the webs and vanes. The cam phaser is configured to automatically locate to its mid-lock position, without having to rely on electronic control. At least one embodiment of the present invention is configured to use cam torque to recirculate oil from one side of the vanes of the rotor to the other.