X2 HEHC Rotary Engine Can Run Multiple Fuels, Requires No Cooling

The nature of the internal combustion engine is harnessing the power of thousands of small, controlled explosions. Alas, most of the energy created is wasted as heat, but a new rotary engine design can almost double the thermal efficiency of almost any kind of fuel while requiring fewer moving parts for a light, powerful, and simple engine design.

Called the X2 High Efficiency Hybrid Cycle engine, it is being developed by LiquidPiston as a project aimed at making a more efficient combustion engine. Right now, most combustion engines can only achieve between 30 and 40% efficiency, which a majority of the energy created becoming waste heat. Today’s engines also have more valves, camshafts, and other complicated moving parts that make them heavy and costly to build.

The X2 HEHC engine combines the benefits of the four different kinds of combustion engines. The X2 has a high-compression ratio like diesel engines, the constant volume combustion of Otto cycle engines, the over-expansion to atmospheric pressure ala Atkinson cycle engines (commonly used in hybrids) and the internal cooling system using air or water of Rankine cycle engines.

What researchers have come up with is an engine that is quieter than current motors, delivers up to 58% thermal efficiency, and an extremely lightweight design that makes around 2 horsepower per 1 lb. of engine weight. Combined with fewer moving parts, it makes for a simple-yet-effective engine design that could lead to big fuel economy gains.

Researchers the world over are looking at new engine designs, from opposed-piston to wave disks to super steam engines. But none have tried to combine the benefits of the four different engine cycles into a single working unit. It’s a bold idea to be sure, one that would offer the world a cheap, lightweight engine that can run a multitude of different fuels.

There is currently a working prototype-grade version of the X2 engine, and researchers believe that they could get as much as 74% thermal efficiency from this engine design. This could triple the fuel economy of even the most efficient cars on today’s market. Imagine what that would do to oil prices and the automotive market. Sounds promising, but the X2 is still a long ways out. Will it ever move beyond the lab?

Source: Green Car Congress

Mazda Re-commits to Rotary Power

At this week’s Moscow Auto Show, Mazda CEO Takashi Yamanouchi reaffirmed his company’s commitment to Wankel’s rotary engine technology – confirming its use in the brand’s first extended-range hybrid offering.

With this year’s demise of Mazda’s rotary-powered RX8 sportscar (and no RX9 yet on the horizon), many in the industry believed that Mazda had walked away from the Wankel for good. It turns out, we didn’t have to worry – Mazda gets it. “We are still learning,” said Yamanouchi, “(but) the rotary has very good dynamic performance, but if you accelerate and brake a lot there are efficiency disadvantages. The range extender overcomes that. We can keep it spinning at it’s most efficient 2000rpm while also taking advantage of its size.”

Additionally, the (relatively new) CEO committed Mazda to the rotary in the longer-term. “When I joined the company in 1967, it was the rotary engine that motivated my decision,” he said. “We continue to explore ways to improve the fuel efficiency and capabilities of the rotary engine so it can be the primary power source of a car again.”

Keeping the small rotary spinning at its peak efficiency as an electrical generator seems like the way to go, for sure. Here’s hoping the Wankel (which is flexible enough to work with hydrogen, gasoline, and bio-fuels) can make the most of theSkyActiv design philosophy (and frikkin’ laser beams) to keep bringing better, more efficient “Zoom Zoom” Mazdas to market for many years to come.

Source: Gas2.0