The eccentric crank engine is a device driven by the moment of the force produced by the constriction and elongation of SMA springs all round the wheels. The heat energy comes from hot water with temperature of 65℃~85℃. Put the engine into the hot water with the core under the water, and the wheels could turn continuously. The engines are readily availble according to the diameter of the big wheel: 120mm and 250mm. The engine could also be provided on customer，s requirement.