Abstract: A new and improved resonant free-piston Stirling engine and method of operation employing a novel virtual rod displacer is described. A rod is secured to and reciprocally moves with the displacer within the Stirling engine and has a rod piston area formed on the end of the rod remote from the displacer with the rod piston area also being subjected to the working gas periodic pressure wave. Suitable support bearings are designed within the Stirling engine housing for reciprocatingly supporting the displacer and rod assembly within the Stirling engine with a set of opposed acting gas springs being provided to act on the displacer end and rod assembly area end of the displacer and rod assembly.

Abstract: An improved transmission from linear power to rotary power in a Stirling heat engine having at least one cylinder with power and displacement pistons linearly operable therein. The power and displacement piston shafts are each interconnected to a common drive shaft through an actuating arm. The power and displacement shaft connections to the actuating arms are through universal joints and their drive shaft connections are rotary connections. The rotary connections of the actuating arms to the drive shaft are eccentrics or cams angularly displaced from the longitudinal center line of the drive shaft and rotatably positioned relative to each other so as to provide the proper operational phase angle of the pistons. A timing shaft running through at least a portion of the drive shaft is translatable a discrete distance to change the relative rotational positions of the eccentrics or cams through 180.degree. of rotation displacement piston eccentric rotates 90.degree. while the power piston eccentric rotates 90.

Abstract: A resonant free-piston Stirling engine having a new and improved start-up and control method and system. A displacer linear electrodynamic machine is provided having an armature secured to and movable with the displacer and having a stator supported by the Stirling engine housing in juxtaposition to the armature. A control excitation circuit is provided for electrically exciting the displacer linear electrodynamic machine with electrical excitation signals having substantially the same frequency as the desired frequency of operation of the Stirling engine.

Abstract: A power control is disclosed for a free piston Stirling engine having a hermetically sealed vessel enclosing a working space in which oscillates a displacer for circulating working gas through a heater, a regenerator and a cooler for creating a pressure wave in the working gas which acts against a power piston for a producing power stroke. The displacer includes a post mounted in a well which forms a gas spring and cooperates with the working gas pressure wave to maintain the displacer in axial reciprocating motion. The post includes a tapered portion which reciprocates opposite a proximity probe to produce a unique signal for each axial position of the displacer to provide stroke, phase and amplitude information regarding the displacer motion. A gas spring volume control is provided, controlled by the displacer sensor, for adjusting the gas spring stiffness to control the amplitude and phase of the displacer required to produce the power to meet the engine load requirements.

Abstract: A mechanical device for effecting a phase change between the expansion and compression volumes of a double-acting Stirling engine uses helical elements which produce opposite rotation of a pair of crankpins when a control rod is moved, so the phase between two pairs of pistons is changed by +.psi. and the phase between the other two pairs of pistons is changed by -.psi.. The phase can change beyond .psi.=90.degree. at which regenerative braking and then reversal of engine rotation occurs.

Abstract: A motion conversion device for converting between the reciprocating motion of the pistons in a Stirling engine and the rotating motion of its output shaft, and for changing the stroke and phase of the pistons, includes a lever pivoted at one end and having a cam follower at the other end. The piston rod engages the lever intermediate its ends and the cam follower engages a cam keyed to the output shaft. The lever pivot can be moved to change the length of the moment arm defined between the cam follower and the piston rod the change the piston stroke and force exerted on the cam, and the levers can be moved in opposite directions to change the phase between pistons.

Abstract: A phase and stroke control apparatus for the pistons of a Stirling engine includes a ring on the end of each piston rod in which a pair of eccentrics is arranged in series, torque transmitting relationship. The outer eccentric is rotatably mounted in the ring and is rotated by the orbiting ring; the inner eccentric is mounted on an output shaft. The two eccentrics are mounted for rotation together within the ring during normal operation. A device is provided for rotating one eccentric with respect to another to change the effective eccentricity of the pair of eccentrics. A separately controlled phase adjustment is provided to null the phase change introduced by the change in the orientation of the outer eccentric, and also to enable the phase of the pistons to be changed independently of the stroke change.

Abstract: A hot-gas reciprocating machine comprises two intercommunicating spaces of variable volume and two pistons (1 and 11) for varying the volumes of these spaces. The two pistons are coupled to two parallel crank shafts (16 and 17) and are movable with an adjustable phase difference. For balancing the engine a system of counterweights is provided comprising a counterweight (30, 31) on each crank shaft and a counterweight (32, 33) on each of two auxiliary shafts (26, 28) which are coupled one to each crank shaft for rotation therewith at the same speed as and in the opposite direction, each auxiliary shaft extending parallel with the associated crank shaft on the side thereof remote from the other crank shaft.

Abstract: A drive mechanism is disclosed for drivingly connecting two reciprocating bodies to a rotating body and is particularly useful for linking a single pin crank of a crank-type Stirling engine to its displacer and power piston. The drive means has at least two slotted yokes, each connected to a different one of the reciprocating bodies such as the pistons of the Stirling engine. The pin of the crank extends through the slots of both slotted yokes. The slots are transverse to each other and preferably are linear.

Abstract: A mechanism is disclosed for driving the displacer of a crank-type Stirling engine at the same frequency but out of phase with the power piston of the engine. A biasing means is linked to the displacer for applying a biasing force which urges the displacer in one direction of its reciprocation. A flexible band is secured to the displacer for applying a force opposite to the biasing force. The other end of the band is secured to an anchor which is mounted on another part of the apparatus. The band extends slideably across at least one and preferably two bearing surfaces intermediate its secured ends.

Abstract: Stirling cycle apparatus including a compressor or expander for cyclically compressing or expanding a working gas, a displacer for cyclically displacing the working gas, a rotatable shaft, and a drive mechanism for coupling the compressor or expander and the displacer to the shaft, the drive mechanism being such that the relative timing of their operating cycles can be altered. Additionally a low vibration compressor or expander is provided.

Abstract: A first embodiment incorporating an actuator including a restraint link adapted to be connected with a pivotal carrier arm for a force transfer gear interposed between the crankshaft for an expander portion of a Stirling engine and a crankshaft for the displacer portion of the engine, said restraint link being releasably supported against axial displacement by releasably trapped hydraulic fluid for selectively establishing a phase angle relationship between the crankshaft and a second embodiment incorporating a hydraulic coupler for use in varying the phase angle of gear-coupled crankshafts for a Stirling engine whereby phase angle changes are obtainable.

Abstract: A hot gas engine in which the expander piston of the engine is connected to an expander crankshaft. A displacer piston of the engine is connected to a separate displacer crankshaft which may or may not be coaxial with the expander crankshaft. A phase angle control mechanism used as a power control for changing the phase angle between the expander and displacer crankshaft is located between the two crankshafts. The phase angle control mechanism comprises a differential-type mechanism comprised of a pair of gears, as for example, bevel gears, one of which is connected to one end of the expander crankshaft and the other of which is connected to the opposite end of the displacer crankshaft. A mating bevel gear is disposed in meshing engagement with the first two bevel gears to provide a phase-angle control between the two crankshafts. Other forms of differential mechanisms may be used including conventional spur gears connected in a differential type arrangement.

Abstract: A rotary Stirling cycle machine is disclosed comprising at least two chambers, said chambers being epitrochoidal in cross-sectional area and having an upper portion, a middle waist portion and a lower portion, with the first chamber mounted to the second chamber in tandem, each chamber having a seal element attached to the waist portion and disposed inwardly, the crank shaft rotatably mounted within the chambers and extending therethrough with the first crank throw portion within the first chamber being 180.degree.

Abstract: In a hot gas engine, for example, of the Stirling cycle type, having a displacer member and associated working piston member, normally moving in respective cylinder spaces with a selected phase relation and having controllable torque output in magnitude and direction, or a plurality of associated displacer piston pairs, the displacer drive affords changeable control of displacer stroke length between a zero or minimum stroke length and a maximum and phase reversal, with or corresponding to a torque requirement of direction and magnitude between a minimum and maximum, thereby to minimize windage type energy losses due to displacer motion at times of low power or low torque demand, and also with displacer stroke length control, controlling torque and output direction.

Abstract: A multi-cylinder self-starting hot gas engine according to the present invention consists of two parallel pairs of opposed displacer cylinders with respective displacer members mounted for movement therein and two parallel pairs of opposed work cylinders disposed parallel to the displacer cylinders and having respective pistons arranged to reciprocate therein; each work cylinder communicating with a respective displacer cylinder to provide a cold end chamber. First transmission connects the displacers for synchronized movement offset in phase within the cylinders and a second transmission interconnects the pistons for synchronized movement offset in phase within the cylinders. An output drive is connected to the pistons.