System for performing an engine braking procedure based on decompression events for a 4-stroke cycle engine

System for performing an engine braking procedure based on decompression events for a 4-stroke cycle engine, the engine comprising at least a cylinder having an inlet pipe and an outlet pipe, cylinder inlet and outlet valves and control means for controlling a displacement of said cylinder valves. The system performs a first compression phase (B-II) followed by a first decompression event (B-II') and, in succession, a sucking phase (B-III) from the outlet pipe and a second compression phase (B-IV) followed by a second decompression event (B-IV').