US Patent 7556015 Rotary device for use in an engine

A rotary device for an engine includes a stator and a rotor concentric with and rotatable about an axis with respect to the stator. The rotor and the stator cooperate to provide a working chamber. A plurality of vanes are supported for radial movement on one of the stator and the rotor. Fluid is taken into the working chamber through an intake port and exhausted from the working chamber through an exhaust port. A biasing device biases each of the vanes to seal against one of the stator and the rotor. An actuator moves each of the vanes radially against the biasing device to a retracted position to vary a thermodynamic cycle of the rotary device as the rotor rotates with respect to the stator.