https://www.indiegogo.com/projects/reve ... g-engine#/
The engine has been successfully tested in several cars, (AMC Spirit DL, 1977 P-40 Opel, 1980 AMC Concord) 50,000 miles (80,467 km) and achieved average fuel efficiency up to 28.5 mpg‑US (8.3 L/100 km)
The MOD II project in 1980 produced one of the most efficient automotive engines ever made. The engine reached a peak thermal efficiency of 38.5%, compared to a modern petrol engine, which has a peak efficiency of 20-25%. The 1986 MOD II Report (1985 4-door Chevrolet Celebrity notch back) showed that highway gas mileage was increased from 40 to 58 mpg‑US (5.9 to 4.1 L/100 km) and achieved an urban range of 26 to 33 mpg‑US (9.0–7.1 L/100 km) with no change in vehicle gross weight.
Disadvantages: Start up time and acceleration, both can easy be overcome with electric hybrids.
http://zigherzog.net/stirling/reports/1 ... 021349.pdf
https://cdn4.explainthatstuff.com/car-s ... engine.jpg
MOD II engine https://static.dvidshub.net/media/thumb ... 0w_q95.jpg
