WARREN, MI - General Motors has received more than $2.6 million in federal funding to develop technology that will let the automaker convert waste heat from car engines into electricity and boost vehicle efficiency. A Shape Memory Alloy (SMA) would generate electricity from the heat in automotive exhaust.

The U.S. Department of Energy grant was one of 37 advanced energy research projects announced Oct.26.

"When you heat up a stretched SMA wire, it shrinks back to its pre-stretched length, and when it cools back down it becomes less stiff and can revert to the original shape" said Jan Aase, director of GM's Vehicle Development Research Laboratory.  "A loop of this wire could be used to drive an electric generator to charge a battery."

It is too soon to identify a vehicle where this technology could work, but hybrid or conventionally powered vehicles are possible applications. "In a hybrid system, the electrical energy could be used to charge the battery. In a conventional engine, this could perhaps even replace the alternator without any load on the engine," said Aase.

The award from the Department of Energy's Advanced Research Program Agency - Energy, or ARPA-E, was the only grant to an automaker among $151 million in distributed by the DOE. GM will work with HRL Laboratories; Dynalloy, Inc., a Tustin, Calif., manufacturer of shape memory alloys specially made to be used as actuators, and the Smart Materials Collaborative Research Lab at the University of Michigan.

The idea of an SMA heat engine "has been around for 30 years," Aase said, but the few devices that have been built were too large and too inefficient to make it worthwhile." 

Over the next two years, GM and its partners will work to create a working prototype.