Vehicle energy harvesting device having discrete sections of shape memory alloy

A method of harvesting energy comprising:

• exposing a first discrete element of a shape memory alloy to heat exchange contact with a first region having a first temperature and a second region having a second temperature that is different from the first temperature, wherein the shape memory alloy has a crystallographic phase changeable between austenite and martensite in response to the temperature difference between the first region and the second region;
• expanding and contracting the first discrete element of the shape memory alloy in response to the temperature difference between the first region and the second region, such that a linear displacement, relative to a fixed ground reference, of at least a portion of the first discrete element of the shape memory alloy occurs in response to the temperature difference between the first region and the second region;
• driving a motion conversion mechanism with the linear displacement of the first discrete element of the shape memory alloy, such that the motion conversion mechanism experiences linear displacement relative to the fixed ground reference;
• and
• driving a component with the motion conversion mechanism;
• wherein exposing the first discrete element of the shape memory alloy to heat exchange contact with the first region and the second region further includes moving a frame having a heat source and a heat sink mounted thereto, wherein the frame moves the heat source and the heat sink relative to the fixed ground reference and relative to the first discrete element such that the first discrete element is alternately in contact with the heat source and the heat sink as a result of movement of the frame relative to the fixed ground reference,
• wherein moving the frame relative to the discrete element further includes moving the frame in response to the crystallographic phase change of a second discrete element of the shape memory alloy.

An energy harvesting system comprising:

• a first region having a first temperature;
• a second region having a second temperature that is different from said first temperature;
• a fixed ground reference;
• a heat engine configured for converting thermal energy to mechanical energy wherein the heat engine includes;
• a discrete element of a shape memory alloy having a crystallographic phase changeable between austenite and martensite in response to the temperature difference between the first region and the second region, wherein opposing ends of the discrete element are fixed to structure other than the discrete element;
• and
• wherein the discrete element of the shape memory alloy expands and contracts in response to the phase change to exert a linear force;
• a frame having one of a heat source and a heat sink mounted to the frame within each of the first region and the second region;
• an actuator to move the frame relative to the fixed ground reference and relative to the first discrete element of the shape memory alloy such that the discrete element of the shape memory alloy is alternately exposed to both the first region and the second region by movement of the frame relative to the fixed ground reference;
• wherein the frame is moved by the actuator based upon the temperature of the discrete element of the shape memory alloy;
• a motion conversion mechanism operatively connected to the discrete element to be driven by the linear force;
• and
• a component driven by the motion conversion mechanism.