AN INTERNAL COMBUSTION ENGINE WITH A DOUBLE-STAGE SEPARATION BLOW-BY GAS RECIRCULATION SYSTEM

An internal combustion engine comprising: - a crankcase (12), - an oil sump (16), - at least one balancing shaft (20) rotatably mounted in a balancing tunnel (22) formed in the crankcase (12), wherein the balancing tunnel (22) has a first end portion (22a), a second end portion (22b) and a central portion (22c) extending between said first and second end portions (22a, 22b), and - a blow-by gas recirculation system (32) having an inlet channel (34) in communication with the oil sump (16), an outlet channel (36) in communication with an intake manifold (37), a centrifugal separator (38) arranged between said inlet channel (34) and said outlet channel (36), and at least one drainage channel (40) which opens into the oil sump (16) for discharging the separated liquid, wherein: - said inlet channel (34) of the blow-by gas recirculation system (32) communicates with said first end portion (22a) of the balancing tunnel (22), - said centrifugal separator (38) is housed in said second end portion (22b) of the balancing tunnel (22) and is driven in rotation by said balancing shaft (20), and - said outlet channel (36) of the blow-by gas recirculation system (32) communicates with a gas outlet (42) of said centrifugal separator (38), whereby, during operation, the flow of blow-by gas flows successively through the central portion (22) of the balancing tunnel (22) and the centrifugal separator (38) in the path from the inlet channel (34) to the outlet channel (36).