INTERNAL COMBUSTION ENGINE WITH GAS FEEDING SYSTEM

An spark-ignition internal combustion engine (1) is equipped with a gas feeding system (2), comprising a plurality of main gas injectors (19) each associated with an intake duct (4) of a respective cylinder (3) of the engine, a gas distribution manifold (18) communicating with said main gas injectors (19), a gas tank (16), connected to the distribution manifold (18), where gas under pressure is accumulated, an electronically-controlled pressure regulation valve (20), which is interposed in the connection (17) between the tank (16) and the aforesaid distribution manifold (18), and an electronic control unit (E) configured to control the pressure regulation valve (20) in order to establish a gas pressure in the aforesaid gas distribution manifold (18), which is determined according to the operating conditions of the gas feeding system (2) and according to the operating conditions of the engine (1). The spark plug (24) of each cylinder is mounted within a support body (25) that defines a combustion pre-chamber (30) and a channel (31) for auxiliary gas injection within the combustion pre-chamber (30), communicating with a respective auxiliary gas injector (36) mounted on the cylinder head in a remote position relative to said combustion pre-chamber (30). The auxiliary gas injectors (36) are all in communication with the gas distribution manifold (18), downstream of the pressure regulation valve. In the channel (31) for the auxiliary injection of gas, a non-return valve (33) and a restricted passage (32A) are provided in series, allowing passage of a gas flow proportional to the volume of the combustion pre-chamber (30).