Patent ID: 8191350

Claim:
An engine supplied with compressed air, or with any other compressed gas contained in a high-pressure storage tank ( 22 ) and comprising: at least one main drive piston ( 1 ) which slides in a drive cylinder ( 2 ) driving a crankshaft ( 5 ) in a conventional connecting rod/crank arrangement, and at least one active expansion chamber which consists of a variable volume equipped with means allowing work to be produced and which is connected, by a passage ( 6 ), with the volume, called dead volume, contained in the driving cylinder ( 2 ) above the driving piston ( 1 ) at its top dead centre, characterized: in that the said passage ( 6 ) comprises a shutter ( 7 ) thus allowing the said active expansion chamber to be isolated from or to be placed in contact with the dead volume, in that the engine comprises an inlet duct ( 17 ) which opens in the active expansion chamber ( 13 ) and which allows the engine to be supplied with compressed air or with compressed gas, in that the compressed air or gas is let into the expansion chamber when this chamber is at its smallest volume and which, under the thrust of the compressed air, will increase in volume, thereby producing a work, in that when the expansion chamber is more or less at its maximum volume and the driving piston is more or less at its top dead centre, the inlet duct ( 17 ) is shuttered, and the said active expansion chamber ( 13 ) is placed in communication with the driving cylinder ( 2 ) and the compressed air, or the compressed gas, which is contained in the active expansion chamber expands, thus pushing the driving piston ( 1 ) back in its downstroke, thereby in its turn supplying a work, in that during the expansion, the volume of the active expansion chamber ( 13 ) is returned to its minimum volume to allow a new cycle to commence, in such a manner that the engine works according to a four-phase thermodynamic cycle: an isothermal expansion without work; a transfer-slight expansion with work said to be quasi-isothermal; a polytropic expansion with work; an exhaust at ambient pressure.