Volvo ReCharge Concept (© Volvo Cars of North America)Click to enlarge picture

Volvo's ReCharge features a lithium-polymer battery and four electric motors, one in each wheel. A small flex-fuel engine serves as a backup generator.

Volvo's new concept car looks like a regular C30, but a plug on the front and some very different insides make this a big step forward. Plug-in hybrids will soon change the way we drive, and Volvo's ReCharge concept car foreshadows a handful of technologies that push the envelope.

With the rising cost of fuel and falling cost of batteries, these advanced hybrids seem to become more inevitable with each passing month.

Unlike fully electric cars, plug-in hybrids still retain a small internal combustion engine that serves as a backup generator or power assist. Volvo's ReCharge, which made its public debut at the Frankfurt Motor Show in 2007, pushes beyond other concepts such as the Chevy Volt into even more ambitious territory.

View Pictures:  Volvo ReCharge Plug-In Hybrid Concept

The ReCharge was developed in California at the Volvo Monitoring and Concept Center (VMCC), a focal point for new automotive ideas. Ichiro Sugioka is the science officer at VMCC, and the ReCharge project is his baby. "I'm not a car guy," Sugioka admits. "Actually, I'm a rocket scientist," he says, referring to his Ph.D. in aeronautical engineering.

The ReCharge isn't quite a spaceship, but in some important ways it is breaking apart the traditional notion of how a car works.

Motors Where You Need Them
The ReCharge is the definition of four-wheel drive. Electric motors are housed within each wheel, eliminating the need to deliver power from a central motor through a mechanical driveshaft. Even the backup motor, a small flex-fuel engine, works to charge the battery; it never drives the wheels directly.

According to Sugioka, kicking out the transmission yields a 10 to-15 percent spike in efficiency, meaning the car's battery can be that much smaller, and the car will use that much less electricity. Also, having all components built into each motor pushes their peak efficiency into the 95 percent range.

Watch Video:  Sugioka talks about the design and function of the ReCharge

The maker of these unique motors is PML Flightlink, a British company whose technology is also favored by electric carmaker ZAP. The units are made of layered electromagnets that can be stacked within the wheel's hub like sideways pancakes. Thirty-six of them in a ring were just enough to encircle the ReCharge's hubs, putting 300 volts inside each wheel — more than enough torque to drive and stop the car.

And because electric motors become generators when turned in reverse, Volvo's completed car will have no disc brakes (or wasted energy from braking friction). With wheel motors, close to 100 percent of the energy from slowing the ReCharge is returned to the battery.

Green Behind the Wheels
Currently the only people enjoying the ReCharge are Volvo engineers on the test track in Sweden. But the technologies rolled into this modified C30 are holding up well.

The car can do 0-60 mph in about nine seconds, with a top speed of 100 mph. On a three-hour charge it will go roughly 60 miles. When the remaining battery level hits 30 percent, the gas/ethanol motor starts charging the battery. Drivers also have the option of toggling manually between electric and internal-combustion modes.

As for emissions, the ReCharge releases nothing when running on electric power. When the four-cylinder flex-fuel motor kicks in to recharge the battery, efficiency will step into the 40-mpg range.

When the ReCharge is "used as intended" it will contribute 66 percent lower carbon emissions compared to the best hybrids now available, says Magnus Jonsson, Volvo's senior vice president of research and development.

This will save money as well as greenhouse gasses. Driving on electric power from a home electric outlet is expected to be about 80 percent cheaper per mile than a comparable car running on fossil fuel.