Abstract: A two stroke steam-to-vacuum engine comprises a plurality of cylinders (500, 502) each cylinder having a piston (504, 510), a piston rod (506, 512), and a steam chamber (508, 514), the piston rods connected for synchronous movement such that each piston is reciprocally moveable between an expanded position and a collapsed position. Admission of steam at 3–5 p.s.i. above atmospheric pressure into the steam chambers (508, 514) is controlled by steam valves (522, 524) and exposure of the steam chambers to a vacuum is controlled by vacuum valves (548, 550). Steam is supplied to the steam chambers (24, 38) through a boiler 520, a solar power source, or an alternative fuel of choice. An auxiliary vacuum tank (572) may be isolated from a primary vacuum tank (554) to replenish the vacuum in a condensate collector tank (560) after removal of condensate.

Abstract: A two stroke steam-to-vacuum engine comprises a first cylinder (12) having a first piston (16), a first piston rod (18), and a first steam chamber (24), and a second cylinder (14) having a second piston (30), a second piston rod (32), and a second steam chamber (38). Each piston is reciprocally moveable between an expanded position and a collapsed position. Admission of steam at atmospheric pressure into the steam chambers (24, 38) is controlled by steam valves (52, 54) and exposure of the steam chambers (24, 38) to a vacuum is controlled by vacuum valves (56, 58). The piston rods (18, 32) are fixed for simultaneous reciprocation such that a power stroke in one cylinder produces a steam intake stroke in the other cylinder. Steam to the steam chambers (24, 38) is supplied through a steam reservoir (42) and a solar power source (44), from a boiler, a fuel of choice, or a variety of alternate sources of heat.