Patent ID: 8607562
Filing Date: 2013-12-17
Classification: F03G

Abstract:
1. A heat engine comprising: a first rotatable pulley; a second rotatable pulley spaced from the first rotatable pulley; a shape memory alloy element disposed about a portion of the first rotatable pulley at a first radial distance and about a portion of the second rotatable pulley at a second radial distance, the first and second radial distances defining a shape memory alloy pulley ratio, wherein the shape memory alloy element includes: a first spring coil; and a first fiber core within the first spring coil; a timing cable disposed about a portion of the first rotatable pulley at a third radial distance and about a portion of the second rotatable pulley at a fourth radial distance, the third and fourth radial distances defining a timing pulley ratio, the timing pulley ratio being different than the shape memory alloy pulley ratio; wherein the shape memory alloy element is configured to be placed in thermal communication with a hot region at a first temperature and with a cold region at a second temperature lower than the first temperature; and wherein the shape memory alloy element is configured to selectively change crystallographic phase between martensite and austenite and thereby the shape memory alloy element contracts and expands in response to exposure to the first temperature and to the second temperature, thereby converting a thermal energy gradient between the hot region and the cold region into mechanical energy.