Abstract: A free-piston engine power plant incorporating a first combustion cylinder, having a first combustion piston, a fluid expander having an expansion cylinder with an expander piston therein, the expander piston reciprocating in unison with the first combustion piston, a bottoming cycle having a working fluid and a heat exchanger.

Abstract: free-piston engine power plant incorporating a first combustion cylinder having a first combustion piston, a fluid expander having an expansion cylinder with an expander piston therein, the expander piston reciprocating in unison with the first combustion piston, a bottoming cycle having a working fluid and a heat exchanger.

Abstract: A heat engine comprising compressor and expander displacement elements (210, 211) reciprocating in respective compression and expansion chambers (111, 111?, 102, 102?) and arranged in a linear, free piston configuration, a combustor (116) separate from the compression and expansion chambers (111, 111?, 102, 102?), and a linear energy conversion device (212, 213) providing conversion of solid, liquid, or gaseous fuel into hydraulic, electric, or pneumatic energy by means of subjecting a working fluid to a thermodynamic cycle with substantially constant pressure combustion. The inlet and outlet valves of the compression chamber (102, 102?) and the rate of fuel injection to the combustor (116) are actively controlled by an electronic controller to avoid engine damage, and to maintain thermodynamic efficiency over a wide range of loads.

Abstract: A linear-acting, free-piston internal combustion engine suitable for operation on a four-stroke engine cycle comprises a power piston (11a, 11b) reciprocating in a power chamber (18a, 18b) and a compression piston (23, 23a, 23b) reciprocating in a compression chamber (29a, 29b). The power piston (11a, 11b) and the compression piston (23, 23a, 23b) are rigidly connected by means of a rod (19). The compression piston (23, 23a, 23b) performs alternately an intake stroke and a compression stroke and the power piston (11a, 11b) performs alternately a power stroke and an exhaust stroke.

Abstract: A linear-acting, free-piston internal combustion engine suitable for operation on a four-stroke engine cycle comprises a power piston (11a, 11b) reciprocating in a power chamber (18a, 18b) and a compression piston (23, 23a, 23b) reciprocating in a compression chamber (29a, 29b). The power piston (11a, 11b) and the compression piston (23, 23a, 23b) are rigidly connected by means of a rod (19). The compression piston (23, 23a, 23b) performs alternately an intake stroke and a compression stroke and the power piston (11a, 11b) performs alternately a power stroke and an exhaust stroke.

Abstract: A heat engine comprising compressor and expander displacement elements (210, 211) reciprocating in respective compression and expansion chambers (111?, 102, 102?) and arranged in a linear, free piston configuration, a combustor (116) separate from the compression and expansion chambers (111, 111?, 102, 102?), and a linear energy conversion device (212, 213) providing conversion of solid, liquid, or gaseous fuel into hydraulic, electric, or pneumatic energy by means of subjecting a working fluid to a thermodynamic cycle with substantially constant pressure combustion. The inlet and outlet valves of the compression chamber (102, 102?) and the rate of fuel injection to the combustor (116) are actively controlled by an electronic controller to avoid engine damage, and to maintain thermodynamic efficiency over a wide range of loads.