SOLID ENGINE

PURPOSE:To effectively use hot and cold heat sources for a solid engine by using a coiled or linear wire of a shape-memory alloy as a drive for the engine and providing auxiliary pulleys located in water vessels, main and sub pulleys, as well. CONSTITUTION:After driven out of a main pulley 1, a coiled spring 3 of a shape- memory alloy is streched. The spring 3 is driven into a hot heat source 5 inside a vessel 11, wherein the spring's tendency of a thermal contraction to the original shape causes a tensile strength f1, and successively driven via an auxiliary pulley 10 to a sub pulley 2. After the spring 3 driven by the sub pulley 2 is cooled by a cold heat source 6 inside another vessel 12, the spring is easy to be stretched by a weak force so that a weak tensile force f2 is generated when the spring 3 is pulled up by the main pulley 1 via another auxiliary pulley 10 inside the cold source vessel 12. The sub pulley 2 whose diameter is shorter than that of the main pulley 1 makes a relative motion with it with the aid of transmission gears 4 so that the main pulley 1 is turned in the direction of an arrow 7 shown in the drawing.