New Reverse Rotary Engine Aims for Extreme Efficiency

New Reverse Rotary Engine Aims for Extreme Efficiency
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Small engine manufacturer LiquidPiston is developing a tiny, lightweight, super-efficient engine that functions a lot like Wankel rotary units.

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

It even looks a lot like a traditional rotary engine, but has a few key differences. For example, the rotor holds the seals in a normal rotary engine, but in this case they sit on the crankcase. It also uses direct injection and a high 18:1 compression ratio.

In fact, the engine is so efficient that it doesn’t require liquid cooling. Instead, it skips an injection cycle if it overheats to suck in cool air instead. Ultimately the unit burns fuel longer, has lower carbon emissions and even weighs significantly less than a diesel engine. For example, LiquidPiston’s latest unit weighs 80 lbs and makes 40 hp. Better still, the company says production versions will weigh less than 50 lbs. For reference, a comparably powerful diesel engine weighs around 400 lbs.

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

[Source: Hybrid Cars]