Abstract: A five cylinder, double-acting hot gas engine having pistons acting on a common crankshaft has been designed with the central cylinder forming a larger V-angle relative its two neighboring cylinders and a smaller V-angle with the two remote cylinders.

Abstract: A heater head for a multi-cylinder solar radiation powered hot gas engine comprises tubes connecting cylinder and regenerator tops. Each tube comprises three parts. A first part of each tube extends along an involute curve on a cone. A second part extends radially outwardly on the same cone while a third part extends radially inwardly and downwardly on another cone.

Abstract: A heater head for a multi-cylinder solar powered hot gas engine has a number of heater tubes lined on a conical wall exposed to the radiation.The tubes follow involute curves in two parts. The first parts leave very small gaps between them. The second parts arranged at a larger diameter from the center of said wall follow another involute each tube now leaving such gap relative its neighbor that a returned tube part may be arranged between.

Abstract: A number of hot gas engine units each having a plurality of pistons working upon two parallel crank shafts may form an assemblage of relative short axial length by axially connecting one crank shaft of each unit to a crank shaft of another unit and locating the other crank shaft of each unit at alternating sides of the axially connected crank shafts.

Abstract: In a cross flow tubular heat exchanger the tubes are arranged in a space between two concentrically, imaginary cylinders. Radially extending baffle plates ensure that the heat exchanging medium flowing outside the tubes and perpendicular to their direction will pass the central cylindrical space without tubes.

Abstract: Apparatus for recirculating combustion exhaust gases to the burner region of a Stirling cycle hot-gas engine to lower combustion temperature and reduct NO.sub.x formation includes a first wall separating the exhaust gas stream from the inlet air stream, a second wall separating the exhaust gas stream from the burner region, and low flow resistance ejectors formed in the first and second walls for admitting the inlet air to the burner region and for entraining and mixing with the inlet air portion of the exhaust gas stream. In a preferred embodiment the ejectors are arranged around the periphery of a cylindrical burner region and oriented to admit the air/exhaust gas mixture tangentially to promote mixing. In another preferred embodiment a single annular ejector surrounds and feeds the air/exhaust gas mixture to a cylindrical burner region. The annular ejector includes an annular plate with radially-directed flow passages to provide an even distribution of the air/exhaust gas mixture to the burner region.

Abstract: The crankcase, monoblock assembly and engine block of a hot gas engine are fixedly interconnected by a locking pin having a cold gas connecting duct. The hot gas engine is comprised of a plurality of monoblock assemblies, each assembly including a cylinder, a heater pipe system and a regenerator-cooler housing. The locking pin passes through bores formed in the regenerator-cooler housing and a cooler unit received therein and includes a cold gas connecting duct which provides communication between the cylinder and the regenerator-cooler housing.

Abstract: A compact six-cylinder, double-acting hot gas engine having a single central combustion chamber with the cylinders arranged in two groups of three and clustered around the combustion chamber axis at equal angular intervals. The engine has two crank shafts, one per group of three cylinders, rotating in the same direction and synchronized. Each crank shaft has three cranks with adjacent cranks angularly displaced 60 degrees. Each of the cranks of one crank shaft is directed oppositely to a respective one of the cranks of the other crank shaft.

Abstract: A heater head for a multi-cylinder, double-acting hot gas engine in which each cylinder is surrounded by an annular regenerator unit, and in which the tops of each cylinder and its surrounding regenerator unit are interconnected by a number of heater tubes. To provide for a single heater head for a plurality of sets of tubes connecting cylinder tops and surrounding regenerator unit tops, arcuately shaped manifolds are provided on the tops to form two complete concentrically disposed circles.

Abstract: Hot gas engine units of the type having four parallel cylinders arranged in two parallel rows of two cylinders per row may be effectively balanced by a minimum of counterweight masses. The engine pistons are connected to two parallel crank shafts and four primary counterweights are positioned on the crankshafts each diametrically opposite a respective crank. The crankshafts engage a common gear wheel rotating opposite to but at the same angular speed as the two crank shafts, and the gear wheel is mounted on a third shaft parallel to the two crank shafts. Secondary counterweights including at least two axially spaced, oppositely directed secondary counterweights positioned on the third shaft are used to cancel the moment about the engine vertical axis produced by the primary counterweights.

Abstract: A hot gas engine of the Stirling type having a cylinder and associated piston, piston rod and cross-head, wherein the seals for the cylinder and piston rod are carried in a seal assembly unit clamped between separable engine housing parts. The seal assembly unit includes a guide for the cross-head.

Abstract: Hot gas engine units of the type having parallel cylinders in two parallel rows and containing pistons connected to two parallel crank shafts engaging a common third output shaft are juxtaposed into an assemblage of four such units. The output shaft is common to all four units and each of four crank shafts is connected to pistons in cylinders of adjacent rows of neighboring units. In such assemblage the total number of crank shafts in four units is reduced from eight to four and one output shaft will replace four output shafts.

Abstract: A scraper ring for removing oil from a piston rod is made of plastic and comprises conical surfaces defining a smallest diameter edge for contact with the piston rod. The ring is axially loaded with Belleville springs and a mating support ring bearing on the scraper ring.

Abstract: In Stirling engines the high pressure of the cycle requires special seals on the piston rod to prevent leakage of gas out of the high pressure cylinder into lower pressure regions such as a crankcase. A liquid oil seal is developed in a chamber around the piston rod by movement of the piston rod to carry oil into the chamber which is limited by an upper scraper member and a lower sealing gland. The chamber leads to a membrane operated pressure comparison valve releasing oil from the chamber when its pressure exceeds that of the gas in the high pressure cylinder. No gas need be pumped back into the high pressure chamber and thus no separation of gas and oil is necessary.

Abstract: Fuel is burned in two chambers, the first with excessive air to produce combustion gases containing oxygen and the second using cooled combustion gases from the first to constitute the oxidizing medium. Preferably the proportions of fuel in the two chambers are equal and the combustion gases are cooled to about 800.degree. C.

Abstract: A sealing device such as a piston ring has an L shaped cross section with primary and secondary sealing surfaces held in contact. The device is mounted in a groove to dispose the primary sealing surface against two relatively movable members and the secondary sealing surface substantially normal thereto.

Abstract: Sealing rings located in an annular recess about a piston in a Stirling engine have a continuous sealing ring of polymeric material having an L-shaped cross-section producing an annular flange abutment. A second discontinuous polymeric ring has a surrounding resilient steel strip resting against the abutment so that internal pressure cooperates with the two rings to effect a seal.

Abstract: A heater head is arranged about the central axis of a multiple cylinder hot gas turbine with a manifold ring of a diameter substantially smaller than the combustion chamber and connected to cylinders and regenerators by heat exchanger tubes extending upwardly therefrom and inwardly toward the manifold.

Abstract: A Stirling cycle hot gas engine is provided with a seal about a moving piston rod for limiting leakage of gas from a high pressure working chamber into a low pressure crank casing. The seal is a conically shaped plastic ring urged against the piston rod by mating spring loaded metal wedge rings.

Abstract: In a double-acting multi-cylinder V-configuration Stirling cycle engine having a single burner unit, the regenerator-cooler units are clustered around a central axis of the heater head with radially extending heater pipes to keep manifold volumes small and temperatures on the heater pipes high.