Working Characteristics of a Reciprocating-Type Heat Engine Using Shape Memory Alloys

Abstract

Various types of heat engines using shape memory alloys are proposed and studied. From the viewpoints of thermal efficiency and operational control of an engine, an efficient heat exchanger is required for heating and cooling shape memory alloys. Furthermore, a heat engine operating in a small range of strain is required because the fatigue life of shape memory alloys is strongly dependent on the strain of shape memory alloys. In this paper, a novel operation system comprising of a reciprocating-type heat engine using shape memory alloys was proposed. This proposed engine could be operated continuously even within a small strain range. The shape memory alloys used were straight wires of a TiNiCu alloy which were heated and cooled by forced convection. The working characteristics of the engine were investigated by experiment. Experiments were conducted at various heating temperatures and under various strains. Working characteristics such as the amount of work are discussed.