Internal combustion engine with cylinders disposed radially around an axis (Z), in each of which slides a piston carrying out reciprocating rectilinear movements, reversibly transformed into a continuous rotation of an output shaft by: an active unit and passive unit each respectively having a planet gear, the axis of which is parallel to (Z), being capable of meshing with a ring gear, being maintained on its orbit via a planet carrier and having a pitch diameter identical to the pitch radius of the corresponding ring gear. The planet gear is driven in rotation by the planet gear and/or the planet carrier. Each planet gear is respectively rigidly connected to a connecting rod having crank pins, the axes of which are parallel to the axis (Z), pass through the pitch circle of the corresponding planet gear and being capable of cooperating by contact with rods rigidly connected to the pistons.

Internal combustion engine with cylinders disposed radially around an axis (Z), in each of which slides a piston carrying out reciprocating rectilinear movements, reversibly transformed into a continuous rotation of an output shaft by: an active unit and passive unit each respectively having a planet gear, the axis of which is parallel to (Z), being capable of meshing with a ring gear, being maintained on its orbit via a planet carrier and having a pitch diameter identical to the pitch radius of the corresponding ring gear. The planet gear is driven in rotation by the planet gear and/or the planet carrier. Each planet gear is respectively rigidly connected to a connecting rod having crank pins, the axes of which are parallel to the axis (Z), pass through the pitch circle of the corresponding planet gear and being capable of cooperating by contact with rods rigidly connected to the pistons.