Catherine Mohr, director of medical research,Intuitive Surgical (l) and Jeff Bonforte, CEO, Xobni

Photographs by Robyn Twomey @FortuneMagazine - Last updated July 31 2012: 1:03 PM ET
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The engine is here to stay

Much has been said about the death of the internal combustion engine. That won't happen any time soon says Caterpillar boss Doug Oberhelman.