Le Mans tech: Are rotary-driven hybrids the future of endurance racing?

By Peter Braun August 8, 2014

It’s been exactly a month since we first covered the InMotion Motorsport team’s insane plan to build a racer capable of shattering records at Le Mans and the Nurburgring. This team of Dutch engineering students is keen to show that their hybrid racer isn’t just vaporware, because their advanced rotary engine is beginning testing.

Though InMotion’s IM01 race car will feature a host of advanced technologies, the most revolutionary aspect is its rotary power plant. The wheels themselves will be driven by four separate electric motors, linked to a battery pack. But the power will come from a rotary generator. This concept is not unlike the range-extended EV powertrain seen in the Chevy Volt.

If InMotion is able to succeed in bringing its IM01 to Le Mans in 2017 as planned, it will actually mark a return of rotary tech to the fabled race. Mazda won at Le Mans in 1991 with its rotary driven 787B. Since then rotaries have been banned from the main race categories.

InMotion 6 — Image used with permission by copyright holder

However, as InMotion hopes to race in the unregulated Garage56 category, this won’t be an issue. Nor will the traditional inefficiency of rotaries across wide rev ranges. Instead, because it will be operating as a generator InMotion’s 545 horsepower rotary can run at its optimal rpm range at all times. This translates into 45 percent efficiency, nearly double that of a standard piston engine – albeit not the 60-percent InMotion originally hoped to deliver.

That decline should actually be taken as good news, because it indicates that not only does InMotion’s rotary engine work, its engineers are actually getting results from running it on a test bed.

An engine in a test facility may be a long way away from a working race car, but it is a crucial start. What is more, the range-extender hybrid concept really might be the way forward in endurance racing. Regardless we look forward to seeing what this plucky band of Dutch students and motorsports folks can accomplish in the next two years.

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Former Digital Trends Contributor

Peter is a freelance contributor to Digital Trends and almost a lawyer. He has loved thinking, writing and talking about cars…

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