Warren, Michigan – General Motors R&D has received funding for research into a special alloy that could potentially transform heat from a vehicle’s exhaust into mechanical energy.

The company received a US$2.7 million federal award that will help build a prototype using Shape Memory Alloy (SMA) that would generate electricity from the heat in automotive exhaust. The captured and converted energy could be capable of powering the vehicle’s stereo, power seats and air conditioning.

“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.”

GM said it is too soon to identify a vehicle where this technology could work, but hybrid or conventionally-powered vehicles are possible applications.

“No one else anywhere in the world is doing this work as far as we know,” Aase said. “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.” Aase said that the idea of an SMA heat engine has been around for 30 years, but the few devices that have been built were too large and inefficient to make it worthwhile.

The award is from the Department of Energy’s Advanced Research Program Agency, which distributed $151 million in grants. This was the only grant to an automaker. GM will work with HRL Laboratories, Dynalloy Inc., and the Smart Materials Collaborative Research Lab at the University of Michigan. It is expected that the partners will create a working prototype over the next two years.

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