Basic Research on Shape Memory Alloy Heat Engine : Output Power Characteristics and Problems in Development

Abstract

In order to develop the shape memory alloy heat engine, basic output power characteristics of three types of heat engines are investigated. As a shape memory alloy, Ti-Ni alloy wire with an outer diameter of 0.75 mm is used. The heat engines employed are the twin crank engine, offset crank engine and simple pulley engine. The results are summarized as follows : ( 1 ) The output power of engines increases with the hot water temperature. ( 2 ) The range of rotational speed where the output power is maximized is wide. ( 3 ) Specific output power is 1-3 W/g. ( 4 ) The maximum output power increases with the number of wire loops of the shape memory alloy. Problems in development of the shape memory alloy heat engine are fatigue strength, welding and corrosion resistance of the material, and the efficiency and mechanism of the engine.