Résumé dans la langue de publication, traduction non disponible The proposed two-stroke internal combustion engine comprises a cylinder with a piston and an aperture to accommodate the intake valve through which the fuel/air mixture passes from the intake manifold into the suction chamber. The suction clamber is situated beneath the piston, isolated from the crankcase and communicates with the combustion chamber. The combustion chamber is situated above the piston and communicates, via the transfer manifold at whose intake is situated the fuel/air supply intake valve, with the suction chamber. An auxiliary piston is arranged in the cylinder between the crankcase and main piston and rigidly connected to the latter. A second suction chamber is provided between the first suction chamber and the auxiliary piston; this second suction chamber is isolated from the first by a baffle plate and communicates with the intake manifold and the transfer manifold.