A system for energy conversion including a closed cycle engine containing a volume of working fluid is provided. The engine includes a double-ended piston assembly including a pair of pistons coupled to a connection member. An expansion chamber is separated from a compression chamber by the piston. The engine defines an outer end and an inner end relative to a lateral extension of the piston assembly. A heater body is positioned thermally proximal to the expansion chamber and thermally distal to the compression chamber, and the heater body is positioned at the outer end of the engine. A load device is operably coupled to the piston assembly at the inner end of the engine. The load device is positioned between the pair of pistons of the piston assembly.

A hot fluid expansion engine has a plurality of actuator modules arranged in a star configuration around a central shaft. Each module includes a drive piston defining a working chamber of variable volume in the first enclosure; a movable displacement piston subdividing a second enclosure into a low temperature chamber of variable volume and a high temperature chamber of variable volume with the high temperature chamber communicating with a unit of a fluid heater device and the low temperature chamber communicating with the working chamber; and a fluid circulation circuit extending between the fluid heater device and the working chamber. The drive piston and the displacement piston of each actuator module are connected to the central shaft via respective first and second eccentric transmission devices suitable for imparting reciprocating motion in translation to each of the pistons with a phase lag of 90.

The double-acting pressure reducing cylinder (1) includes a cylinder shaft (71) which cooperates with a double-acting pressure reducing piston (2) connected to transmission elements (3) housed in a transmission casing (8), while a hollow pillar (13) whose ends are articulated is traversed by a rod tunnel and bears against the casing (8) to support the shaft (71), a tie rod (17) likewise articulated traversing the tunnel to clamp the cylinder shaft (71) to the hollow pillar (13), while lower centering elements of the cylinder (20) and upper centering elements of the cylinder (21) integrated with the transmission casing (8) in particular via a centering frame (22) allow the cylinder shaft (71) to move freely in parallel with its longitudinal axis but not in the plane perpendicular to the axis.

An external combustion engine is disclosed. The external combustion engine includes a working fluid and a burner element, at least one heater head defining a working space, at least one piston cylinder containing a piston, a cooler, a crankcase including a crankshaft for producing an engine output, a rocking beam, a piston rod connected to the piston, a rocking beam driven by the piston rod, and a connecting rod connected at a first end to the rocking beam and at a second end to a crankshaft to convert rotary motion of the rocking beam to rotary motion of the crankshaft. The external combustion engine also includes an airlock space separating the crankcase and the working space for maintaining a pressure differential between the crankcase housing and the working space housing and an airlock pressure regulator connected between the crankcase and one of the airlock space and working space.