F01L 13/0042

Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations {for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction with cams being profiled in axial and radial direction}