Funny how any time someone offered an alternative engine to the reciprocating piston internal combustion engine, they were shouted down and ridiculed. As for example, my uncle, Troy McClure, of Oakdale, California, who, in 1978, invented a circular piston external combustion engine based on the Sterling Hot Air Cycle. He had several patents over the years, the last one in 2000. He died 3 weeks ago, penniless and no success getting anyone remotely interested in the engine. His schematics and prototypes lay in his abandoned shop, collecting cobwebs while his widow wastes away in a nursing home. He always had a dream he would be successful in his endeavors. He was a physics genius but had no serious backing from any major corporations. Sad, because it could be the answer to our energy woes.
Here is a link to a site that details some of his patents:
External combustion rotary engine - US Patent 5961310