Small engine manufacturer LiquidPiston is developing a tiny, lightweight, super-efficient engine that functions very similarly to Wankel rotary units.

Nevertheless, LiquidPiston says that they can deliver 50 percent efficiency compared to a traditional gasoline engine, which only returns about 30 percent energy efficiency. The engine’s design borrows from a variety of different engine types, but follows the Wankel rotary most closely and can burn diesel or other fuels.

Even though it looks a lot like a traditional rotary engine, there are a few key differences. For example, the rotor holds the seal in a normal rotary engine, but in this case they sit on the crankcase. This engine also uses direct injection and a high 18:1 compression ratio.

This engine is so efficient that is doesn’t require liquid cooling, instead it skips an injection cycle if it overheats to suck in cool air. The most significant factor of this engine is that it burns fuel longer, has lower carbon emissions, and even weighs significantly less than a diesel engine. For example, LiquidPiston’s latest unit weight 80 lbs. and makes 40 hp In addition, the company says that production versions will weigh less than 50 lbs, and in comparison, a powerful diesel engine weighs around 400 lbs.

LiquidPiston CEO Alexander Shklonik said that engines are likely to be used in niche market products like military vehicles and plug-in hybrids first.