New distribution system used for opening and closing valves, in a four -stroke interna l combustion engine, of the same valves and, consequently, of a new test structure. The invention allows the opening and closing of valves by rotation around an axis.

摘要

A rotary valvetrain system, with a curved valve control stem, for opening and closing valves in a four-stroke internal combustion engine, allows a decrease in the dissipations and load losses, with the maximum system compactness, and it comprises: a valve (7; 16) with curved stem (30; 34); a rocker arm (9; 18) constrained to said valve (7; 16), having a respective spindle (10; 19) and recesses (9d, 9e) for housing a pair of disk-like cam followers (12; 21) and respective backlash-recovering plates (13; 22) interposed between the corresponding disk-like cam follower (12; 21) and said rocker arm (9; 18); a valve guide (14; 23) inserted in a respective seat at a duct which is opened and closed by said valve, wherein said curved stem (30; 34) slides sealingly; a sealing spring (15; 24) acting on said spindle (10; 19) to bring the valve (7; 16) in closing position; and a camshaft (25; 26) acting on said cam followers (12; 21).