Sure, hybrids don't have the greatest reputation for driving appeal.

But would you feel better about saving gasoline if you knew that the hybrid system in your car used Formula One technology?

That's just what Volvo has done in an engineering prototype it's now testing in Sweden, which adds an F1-inspired Kinetic Energy Recovery System (KERS) to the rear wheels of a front-wheel drive Volvo S60 sedan.

The goal is to save fuel, just like a conventional hybrid-electric vehicle, and Volvo said last month its system can improve fuel efficiency up to 25 percent.

And now Volvo has let a few journalists drive it.

The Volvo system captures kinetic energy when the car slows or brakes and uses it to spin up a carbon flywheel, which rotates in its enclosure at up to 60,000 rpm.

Total energy recaptured is roughly 0.15 kilowatt-hour, or about one-fourth the amount in the smallest high-voltage battery packs used in mild hybrids. It can store energy for up to 30 minutes before it dissipates.

It can deliver up to 80 horsepower to the rear wheels on acceleration, in addition to the output of the regular 254-hp turbocharged five-cylinder engine that powers the front wheels.

According to Green Car Reports, which has a detailed test-drive report, the prototype's "gasoline engine is noticeably less strained" even on a steep incline when the kinetic-energy system kicks in.

Under light loads, the flywheel can power the car by itself, with the engine switched off completely. In Sport mode, the system acts like a Boost function--just as in the Porsche 911 GT3 R Hybrid race car, helping reduce acceleration time. Volvo says the prototype's 0-60 mph time of 5.5 seconds is fully 1.5 seconds faster than a stock Volvo S60 with the T5 engine.

Green Car Reports noted that the engineering prototype has no sound insulation, so in operation, the system sounded like "a jet engine crossed with a laser rifle."

Volvo thus far is not discussing any production plans for the system, but the lack of a battery pack, electric traction motor, and high-voltage power electronics means such a system is almost surely cheaper in volume than today's hybrid-electric powertrains. At 130 pounds for the complete system, it's not only less expensive but also considerably lighter than hybrid-electric systems, too.


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