[samwichse]

They've been awarded a military research contract to make a very compact generator for howitzers:

https://newatlas.com/military/liquid...rmy-generator/

This posting has a nice summary of the advantages over a standard wankel
https://tech.slashdot.org/comments.p...0&cid=60840426

- Seals: Wankel seals are on the rotor, shaken, hard to lubricate. Were a big maintenance problem. LiquidPiston seals are on the stator, unmoving, constantly rubbing in one direction. Can be lubed easily via lube passages in the stator. Better than piston rings for reliability.
- Two moving parts, one just rotating smoothly, the other rotating smoothly around an axis on a smoothly rotating crank offset. (Note the gear on the rotor riding a circular gear track, like a planetary transmission with one planet gear and no sun gear.) Add counterweights to the crank and no vibration from the moving parts. Harmonics only come from the pressure curve of the combustion gasses. With one rolling race, three bearings, a few sliding seals, all lubricated, and smooth motion you have minimal opportunities for wear or early breakdown mechanisms.

Besides the factors pushing longer life there are other advantages:

- Well shaped combustion chambers and constant-volume combustion for substantially more efficient pressure/volume cycle. Also: The high compression ratio and long-time constant volume combustion mean you can burn slow burning stuff like diesel fuel (and design it to run as a diesel), or darn near anything else you can atomize.
- Lightweight small rotor driving THREE combustion chambers for three power strokes on two turns of the shaft. Equivalent to a three piston engine but with only two moving parts. Makes for a smother power cycle, too. (The Wankel needed two rotors to avoid major fluctuations in torque.)
- Tiny weight for a phenomenal 1.5 horsepower per pound! Call it 1,115 watts per pound, or close to a kilowatt after generator inefficiencies. Two pounds of engine drives a house. 14 pounds drives a hybrid car.
- RPM suitable for direct drive of a generator on a common shaft.