Free Republic

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...

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...