Abstract: In a transmission system for four-wheel-drive motor vehicles with a front-mounted engine and gearbox disposed transverse the longitudinal axis of the motor vehicle, of the type including a front differential and an intermediate differential both housed in a casing rigid with the gearbox, the intermediate differential is located within a part of the gearbox while the front differential is housed in a separate casing fixed to the gearbox. The steps necessary to adapt a system provided initially for front-wheel drive only so as to also allow rear-wheel drive is thus simplified.

Abstract: A heat recovery system for the production of mechanical energy from a plurality of different heat sources at different temperatures comprises a plurality of heat exchangers associated one with each heat source, a plurality of circuits for a working fluid which traverses the heat exchangers, the circuits including expansion devices in which the working fluid is expanded and possibly vaporized to derive mechanical work from it, this being accompanied by a fall in temperature; the circuits for the working fluid have certain parts in common, such as the heat exchanger associated with the heat source at the lowest temperature, at least one of the expansion devices, a condenser in which working fluid vaporized in the expanders can be recondensed, and a circulation pump for driving the working fluid around the circuits.