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LiquidPiston says its new XTS-210 solves the efficiency, lubrication and fuel type issues of Wankel rotary engines. This supercharged, liquid-cooled two-stroke claims 5X the power of an equivalent size or weight diesel engine, and 3X the torque. Targeted at military, commercial and aerospace applications, the XTS-210 is about the size of a basketball, weighs in at 19 kg (42 lb), and displaces 210 cc. It'll run on multiple fuels, including diesel and kerosene/jet fuel. The company is shooting for about 20 kW (26.8 hp) and 29.4 Nm (21.7 lb-ft) of torque, both at 6,500 rpm. These numbers compare favorably against...

A Florida team working with the US Air Force claims that it's built and tested an experimental model of a rotating detonation rocket engine, which uses spinning explosions inside a ring channel to create super-efficient thrust. While space propulsion is the key driver for this research, it also has potential terrestrial uses in other cases where high power and low fuel consumption could make a big difference. In 2012, the Naval Research Laboratory estimated that rotating detonation engines could save the Navy 15-20 percent off a ~US$2-billion annual fuel bill if they were retrofitted in place of the gas turbine...

Christian von Koenigsegg's namesake company is small, but it builds some of the most advanced supercars in the world. The Regera, for example, is a 1500-horsepower plug-in hybrid that doesn't have a gearbox. It's incredible. What a lot of people don't know, though, is that Koenigsegg has a sister company called Freevalve. And Freevalve is working to sell the world's first camless engine. By getting rid of camshaft and the throttle body, Koenigsegg says you get better power, torque, efficiency, fuel economy, and emissions. It's an engine that can run on multiple fuels, run as a two-stroke, use the Atkinson...

As automakers augment the reciprocating piston engine with hybrid systems and improved accessories, independent inventors are busily working to make huge improvements to the basic efficiency of the internal combustion engine. Novel designs are popping up at engineering expos everywhere, and the newest comes from Bloomfield, Conn.-based LiquidPiston. Its X1 engine is a simple machine with just three moving parts and thirteen major components, but it aims to raise thermal efficiency from the 20 percent of a normal gas engine to more than 50 percent, with drastic reductions in weight and size. How? By wasting much less energy during the...

The Liquid Piston engine. A) full housing. B) Transparent housing showing principle components. LiquidPiston, developers of a new engine architecture they claim will achieve 50% fuel efficiency (compared to the ~30% of existing engines) and drastically reduce pollutant emissions (earlier post), closed a $1.25 million seed investment round with Adams Capital Management and Northwater Capital. The architecture is based on a “High-Efficiency Hybrid Cycle” (HEHC) thermodynamic cycle, which borrows elements from Otto, Diesel, Atkinson and Rankin cycles. The HEHC cycle can be implemented in a variety of ways; LiquidPiston is developing an implementation that uses a separate rotary compressor, two...

The rumor is now a fact: Mazda announced today that it would bring back the legendary rotary engine, though not as the main powerplant of a car. Instead, a version of the rotary will act as a range extender in one of two electric vehicles the brand will debut for 2020. As Popular Mechanics noted in our recent feature about the story and legacy of the Wankel rotary, the engine hasn't been featured in a car since the Mazda RX-8 was canceled in 2018. But there have been rays of hope for the rotary faithful. Specifically, rumors swirled earlier this...

Wankel engine [Wankel Engine in Deutsches Museum, Munich, Germany]The first working prototype of the Wankel rotary engine ran for the first time on February 01, 1957 The Wankel rotary engine is a type of internal combustion engine, invented by German engineer Felix Wankel, which uses a rotor instead of reciprocating pistons. This design delivers smooth high-rpm power from a compact, lightweight engine; however, Wankel engines have been criticized for poor fuel efficiency and exhaust emissions. Since its introduction in the NSU Motorenwerke AG (NSU) and Mazda cars of the 1960s, the engine has been commonly referred to as the...

Remember this- 'Piston engine goes boing, boing, boing, boing boing, boing... but the Mazda goes hmmmmmmm.' [YouTube] If you've ever driven a car with a rotary engine like a Mazda, it really is a lot of fun, very torquey and revs like crazy, always super smooth (except most from the 70s tend to backfire)- it's a shame the couldn't make them work out in a more substantial way. Besides smoothness of operation, the motor is compact, light, and simple, with only two moving parts. But in an example of epic bad timing, Mazda launched the Wankel-engined RX series just was...

Check out the video, the engine is small, model airplane size via the use of the propeller to give it a load, but it runs.Wankels are notorious for lack of thermal efficiency, but to keep all the heat in and turn it into motion via ceramics could be a game changer.Think about it;* Omnivorous* Smooth* Small in size.* It is uncooled, but is it unlubricated (?)

World’s Smallest Rotary Engine Highlighted May 25, 2009 — The smallest rotary motor in the world keeps your body humming.  It also keeps bacteria, plants, polar bears, giraffes, salmon, sea urchins and just about everything else humming.  It’s a nano-wonder called ATP synthase.  This molecular motor has been reported many times in these pages, but not recently; what’s new?  The state of our knowledge about ATP synthase was summarized in a paper in Nature by three German scientists.[1]  Basically, it’s a fascinating machine, but there’s still a lot more to learn.     It’s not just figurative speech to call...

Saw a commercial for the new Mazda RX-8 tonight, which highlighted that brand's use of the Wankel Rotary engine. Hadn't thought about that engine in a long time and started wondering if any motorcycle company had ever tried using it as a power plant. You'd think the Rotary engine would be a natural -- no valves to adjust, fewer moving parts, less vibration (with counterbalancers), possibly better gas mileage, etc. Did a search and found out that it HAS been tried briefly by at least one (and probably more) company, Suzuki, during the mid 70s. Turn out the design didn't...