This inside-out design solves most of the rotary engine’s problems
LiquidPiston's designs will show up first in UAVs and generators.
@arstechnica
A little bit late.
@arstechnica Doesn't solve carbon dioxide emission. AT ALL.
@wonka @arstechnica Yeah... This is going to have the same leaking ring-seals and wiper problems. 
@gpumoto @wonka @arstechnica well, they did test this new rotary engine with #Hydrogen. Though, if it has leaky seal problems with liquid fuels, it's hard to imagine it would be less of a problem with hydrogen.
Cc: @Hypx
@mcrocker I cannot really imagine an ICE burning hydrogen being more efficient than a hydrogen fuel cell driving electric motors. @gpumoto @arstechnica @Hypx
@wonka @mcrocker @arstechnica @Hypx It is not and an ICE will never be very efficient as the heat energy being produced is mostly wasted.
@wonka @gpumoto @arstechnica @Hypx agreed. ICE engines are not very efficient, but when they are designed to burn hydrogen they're at lot cleaner than when they burn hydrocarbons. As a transition technology or for various corner ceases, some consider them to be a useful technology in this mode.
For example Battery Electric Vehicles are not very cost effective and PEM fuel cells are expensive and have some temperature limitations that might make a small hydrogen powered hybrid a better choice.