Abstract: Power is transmitted by motor shaft 9 in derivation by means of an epicycloidal train of engaged gears 21 to the hydrostatic system 15 mounted in parallel to the mechanical transmission 16 which comprises an inverter 24 upstream of the output of hydrostatic motor 20. A hydraulic coupler 25 controlled by structure 26 is mounted in parallel to the epicycloidal train of derivation of force 21 in a fashion to permit the addition of a supplementary couple in difficult situations.The hydromechanical system of the invention conserves the qualities of flexibility of the hydrostatic system while improving the efficiency of the transmission.Application to the transmission of direction of tracked vehicles.

Abstract: Change-speed transmission providing multiple forward speeds and at least one reverse speed. An output shaft of the transmission carries a first speed pinion or gear that is rigid with a hollow shaft that carries, in turn, a gear or pinion of the reverse gear train disposed upstream of other forward speed gears or pinions. The reverse gear carries a dog that is separated from a dog carried by the closest forward speed gear by a dog and synchromesh unit. A layshaft mechanism is positioned parallel to the output shaft to increase the number of gear ratios provided by the transmission.

Abstract: An engine cooling system comprises a radiator through which a cooling air flow is induced by means of a fan. The cooling air flow is divided into a main stream and an auxiliary stream. Gases to be cooled, for example the exhaust gases of the engine, are mixed with the auxiliary air stream and are discharged via an outlet duct.

Abstract: A synchronizing and dog coupling device for a motor vehicle gearbox in which there are two pinions arranged to be coupled selectively to a drive shaft of the gearbox comprises a coupling ring which is engaged through a driving collar for rotation with the drive shaft and which has a plurality of radial bars, a double synchronizer ring having conical friction surfaces for co-operation selectively with friction surfaces on said pinions, and locking surfaces on said synchronizer ring and said coupling ring bars co-operable to prevent engagement of said coupling ring bars with dog teeth on one or other of said pinions until the speeds of said coupling ring and said pinion are synchronized, the synchronizer ring being braced by a set of rocking keys each of which is located in an axial groove in the driving collar and is arranged to rock on a radially outwardly biassed thruster, each key having first and second sloping sided transverse notches for co-operation respectively with the coupling ring and the thruster s

Abstract: A Diesel engine comprises a set of starting cylinders and a set of power cylinders; and an injection pump including two sets of plunger pistons, one said set of plunger pistons being associated with the starting cylinders for supplying fuel to the starting cylinders and the other set of plunger pistons being associated with the power cylinders for supplying fuel to the power cylinders. Emission of unburned hydrocarbons and nitrogen oxides is reduced as compared with conventional Diesel engines.

Abstract: A heat engine comprises at least one recycling cylinder having a relatively high compression ratio, at least one motive cylinder having a relatively low compression ratio and means for passing exhaust gases from said at least one motive cylinder to said at least one recycling cylinder, said at least one recycling cylinder providing motive power only during starting operation of the engine.