This valvetrain system allows virtually complete variation of the valve lift curve on an internal combustion engine.
The UniAir system is composed of a mechnic-hydraulic actuator with integrated electro-hydraulic solenoid valves and a valve control software which is implemented in the engine control system. The actuator is operated mechanically by a camshaft with it's cam profile and the engine valves connected via a defined oil volume (i.e. hydraulic rocker arm.) This oil volume can be controlled by activating the hydraulic solenoid valves resulting in a variation of valve timing (opening & closing) and maximum valve lift height. Furthermore you can do multilifts during one cam revolution.
This technology yields considerable reductions in fuel consumption and emissions as well as significant improvement of the torque curve across the engine's speed range.