THE GMR 4-4 “HYPREX” ENGINE A CONCEPT OF THE FREE-PISTON ENGINE FOR AUTOMOTIVE USE 570032
DESCRIBED here is a 250-hp free-piston gasifier-turbine engine that has actually been installed in an automobile.
A unique feature of this Hyprex engine is that it is a siamesed unit. The overall design has been selected, according to the author, to secure a compact, light-weight machine with improved thermal efficiency and with a reduction in general noise.
Although the engine is still in the experimental stage, the author reports that analysis and results indicate it will be a serious contender for powering automotive vehicles.