Internal-combustion engine with forced recirculation of exhaust gas

The engine (1) has a collecting combustion cylinder (C3) including a cubic capacity (VC3) provided to be different from cubic capacities (VC1, VC2) of combustion cylinders (C1, C2) if a desired recirculation level is different from an inverse of number of the combustion cylinders. The cubic capacity is provided to be different such that a ratio of the cubic capacity to a total cubic capacity of all the cylinders corresponds to the recirculation level. A commutation valve (11) moves from a recirculation configuration in a closed circuit to an exhaust configuration in an open circuit. The valve is interposed between an upstream capturing collector (7) and a downstream recirculation pipe (8).