Revetec, a little known company from the Gold Coast region of Australia, may be on to something huge: they’ve created an engine that is 50% smaller, 50% lighter, has 50% lower emissions and is cheaper to manufacture than a conventional internal combustion engine of the same horsepower. Oh yeah, did I mention that it doubles the fuel economy too.
A very interesting little rotary/piston hybrid. The animation above shows how the pistons on opposite sides take turns pushing inward and forcing the lobes of the large triangular cams apart. Though, I'm unsure if this engine has more or less reciprocating mass than a conventional inline or V piston engine. The valve train looks more complicated than conventional also.
On the upside, they're claiming it's cheaper to manufacture than conventional piston engines, and the third-party verified efficiency figure of 38.6% efficient is eye-popping for an internal combustion engine. The shape may be useful also, it's a lot flatter than a conventional "block" engine. Get more mass closer to the CG of the car.
Incidentally, if you think this is a new idea, it's not. Russel Bourke built and ran a perfectly functional similiar engine back in the 1930's. There are plenty of other examples of similiar "low RPM, high torque" engines as well.
Although I think electric motors and some kind of turbine/super-cap system for energy storage and (re)generation are the answer for future cars, I still love these new engine designs. The imagination, skill and cleverness that goes into them is always fascinating.