Yeah, old engine designs are fun to look at. Think of all the added friction. There was a dual piston combustion chamber design that was out recently, but it had a single crankshaft. I can't remember what it was called though.
The more I research this sort of stuff, the more I am convinced that either the oil companies, the government, or the auto makers don't want mechanical engine technology to advance. The Wankel was ok because in spite of it's incredible volumetric efficiency, it had issues that didn't make it a good choice for all autos. That one could possibly be coming back in hybrids due to the small size. Audi is looking into ceramic rotaries in a series/parallel hybrid design.
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Originally Posted by the user formerly known as ZX3_Chick
You're special aren't you.