This invention relates to an internal combustion engine comprising: a combustion chamber having at least one rigidly fixed inner wall surface and at least two movable inner wall surfaces reciprocally mounted and adapted to reciprocate from a first position lessening the internal volume of the combustion chamber to a second position expanding the internal volume of the combustion chamber; the two movable, inner wall surfaces are adapted to remain in the first position lessening the internal volume of the combustion chamber of a crankshaft means operatively attached to each of the movable, inner wall surfaces; a spark plug secured in the combustion chamber and having the spark gap terminals thereof extending into the combustion chamber; and a pair of inlet and exhaust valves disposed in the combustion chamber and opening inwardly thereinto complete the major components of the novel engine. In another embodiment, a conformable member is provided which acts upon a contained fluid to obtain work from the combustion of fuel. In yet another embodiment, the combustion chamber has at least three movable inner wall surfaces reciprocally mounted and adapted to reciprocally move as described above. Means are provided for translating the reciprocal linear motion of the walls into rotary motion suitable for coupling into a crankshaft.

A gravity actuated thermal motor which includes a rotor preferably in the form of a ring-shaped annulus which is filled with water. A plurality of collapsible bellows are connected to and extend inwardly from the outer peripheral wall of the annulus into the water-filled chamber. In communication with each of the bellows and extending outwardly from the outer peripheral wall of the annulus are a plurality of refrigerant-containing tanks, one tank being in communication with the interior portion of one bellows. A source of heat in the form of a hot water trough is positioned at the lower portion of the rotor so as to be intercepted by the refrigerant containers upon rotation of the annulus. The vapor produced by the volatile refrigerant expands the bellows and a locking device secures the bellows fully extended on the ascending side of the annulus. An automatic lock release is positioned near the top of the path of travel to release the bellows to enable same to contract during the time that the bellows at the bottom position is expanding. The constantly expanded bellows on the ascending side of the annulus ensures that the water within the annulus remains on the descending side to thereby impart rotary motion to the annulus which may be coupled out via a centrally positioned shaft.

An energy convertor machine generally includes an elongated member and at least two sets of one or more elastomeric bag members, each elastomeric bag member having a liquid with a low vaporization temperature disposed therein, wherein heating means and a cooling means are provided, wherein one set of elastomeric bag members is being heated while the other set is being cooled thereby causing one set of elastomeric bag members to be expanded while the other set of elastomeric bag members are contracting. A means for rotating the elongated member is provided, wherein the rotating means is activated by the alternate expansion and contraction of the two sets of elastomeric bag members.