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How the Hüttlin Spherical Engine Works

What is a range extender (in an automotive context)?
The Hüttlin Spherical Engine on display at the Geneva Motor Show in 2011.
The Hüttlin Spherical Engine on display at the Geneva Motor Show in 2011.
Courtesy of Innomot AG

The Hüttlin Spherical Engine would look kind of goofy rollin' around under the hood on its own, but no worries: it was designed to be part of a system, not a stand-alone power source.

A "range extender" is basically what distinguishes a hybrid vehicle from a pure electric vehicle. It's the additional power source that allows a hybrid to surpass an electric's limits of usability. Since range is often cited as one of the main concerns that prevent electric cars from earning widespread acceptance, this distinction plays a significant role in how the two types of vehicles are perceived.

Finding a reliable range extender, though, isn't quite as simple as perusing the ads at the back of men's magazines. In early hybrids, the range extender was simply an efficient gasoline engine that helped the electric motor bear the load, and the design looked much like an ordinary engine: an electricity generator provided the juice to pump a shaft that, in turn, moved the rest of the engine's parts, which got the fuel-burning cycle underway. Many hybrids on the road still operate like this, more or less, though different manufacturers may emphasize, say, "normality" over efficiency, with the car's drivetrain engineered to favor one power source as opposed to the other. (Though hybrid technology's come a long way in just a few years, the basic layout options haven't changed much.)

Now, though, different types of motors are being developed to help push the game along, and are testing the limits of hybrids' capabilities. Some range extenders run at a constant clip; others kick in only when the electric engine needs a bit of stimulation. Some of the designs are still pretty straightforward, inspired by and drawing from traditional automotive technology. And others, as we've seen...well, they're out there.

Dr. Hüttlin and his team came up with a new design that rolls in the face of established and accepted engine design principles. Instead of wrapping his design around typical mechanics (the common shaft and generator setup), he wanted a more sleek and functional design, a largely self-contained engine that created its own power to get rolling. His design reflects the thinking that a range extender shouldn't squander the hybrid's resources; it should be light, compact, economical, and as inexpensive as possible. This isn't a new idea, but it made him realize it might be worth the effort to go back to the drawing board.

Reconsider that approach after reading the next page...and the Hüttlin Spherical Engine might seem a lot less whimsical and quite a bit more graceful.