Abstract: A heat recuperative engine is provided with an improved heat recuperator having two branches. Each branch houses a pair of meshed gearlike rotors that extend across the chamber of the housing to form a blockage between the inlet and outport ports of the chamber. The rotors are formed similarly to external spur gears and have a central cylindrical body bearing radially projecting teeth or lobes which mesh to form a sealing line of contact that maintains the blockage when the rotors turn. Each rotor of the pair has its projecting teeth or lobes fitting closely with a segment of the chamber wall in which an array of heat pipes is embedded. The spaces between adjacent lobes of a rotor provide constant volume enclosures as the lobes sweep around the closely fitting chamber wall segment and carry working medium from the inlet to the outlet side of the chamber.

Abstract: The invention resides in a fuel efficient internal combustion engine employing a substantially constant volume combustion method and a moderate equivalent compression ratio. The engine has an air compressor connected to the intake port of the first cavity of a two cavity combustion chamber and substantially all the compression of the working medium is performed outside the combustion chamber by that compressor. In the combustion chamber, fuel and the compressed working medium are burned at substantially constant volume. Each cavity of the combustion chamber houses a piston whose motion alternately increases and decreases the cavity volume. The maximum volume of the first cavity is smaller than the maximum volume of the second cavity, to which it is connected by a duct. The duct connecting the two cavities serves as the only gas outlet of the first cavity and the only working medium inlet to the second cavity. Every downstroke of the piston in the first cavity is an intake stroke.

Abstract: A heat engine employs counterrotating rotors disposed in different cavities of a stator. The engine provides a heat recuperator which removes heat from working medium confined in a rotating constant volume chamber in one cavity and utilizes that heat to heat working medium confined in a rotating constant volume chamber in another cavity. Each rotor carries partitions forming separate chambers in its cavity and each cavity has a blocking means which permits the partitions to pass but prevents working medium from making a complete orbit in the cavity whereby the working medium is caused to flow from one cavity to another through ducts disposed near the blocking means.