Abstract: Motive power unit comprising an internal combustion engine associated with a hydrostatic transmission, in particular for fitting to an automobile vehicle.In accordance with the invention, the motive power unit comprises an internal combustion engine (60) mechanically coupled to a hydrostatic transmission device comprising at least one pump (12) with a piston (13) driven by said engine and an elastic accumulator coupled to the or each pump; the pumps being connected to a volumetric motor (14).

Abstract: Piston for internal combustion engine, such as for a free piston engine, of the type comprising one assembly of two co-axial pistons, the inner cylinder having an external diameter which is substantially less than the inner diameter of the outer cylinder, thus defining a closed annular chamber designed to receive a cooling fluid. Longitudinal ribs are provided in the closed annular chamber which ribs extend over most of the height of said chamber and are inclined in alternate directions with respect to the piston axis, thus defining in said chamber, a succession of adjacent longitudinal channels whose section increases from one end of the piston to the other.

Abstract: The invention relates to a distribution system for the intake and exhaust in an internal combustion engine.According to the invention, a cylinder is connected to an exhaust manifold by means of a connecting valve 10. An intake mainfold 10 opens into the manifold 14 by means of an intake valve 14 making it possible to regulate the flow of air and re-cycling of the burnt gases.The advantages attained by the invention include: achieving optimum characteristics of the flow of air and re-cycling of the burnt gases, obtaining optimum characteristics of the flow, reduction in temperature of the exhaust valve and assisting in starting and partial running.