Protean's principal applications engineer, Tom Prucha, told AutoblogGreen the hybrid uses two in-wheel motors – one in each of the rear wheels – in what Prucha calls a through-the-axle hybrid setup. Both the 2.2-liter diesel engine under the hood and the in-wheel motors power the rear wheels, with the system deciding which powertrain to use at any given moment. The two in-wheel motors add over 200 horsepower and give the car an 0-62 acceleration time of 7.4 seconds while boosting fuel economy by up to 30 percent thanks in part to a 15-kWh lithium-ion battery.
Each in-wheel motor contains more than just the motors: brakes for regen and, unlike some competitors' in-wheel motors, an inverter. Now, putting all of that extra stuff into a wheel adds a lot of unsprung mass, which is usually considered a bad thing. As Ken Stewart, vice president of business development at Protean Electric, says in the video below, the amount of weight that the in-wheel motors add can be tuned out by adjusting other dynamic elements, like mounts, springs and struts. Prucha, too, said that dealing with unsprung mass has a lot to do with the overall weight ratio, not just that it exists. Plus, putting the unsprung mass into the wheels that aren't driving the vehicle helps. Companies that used to scoff at the idea of in-wheel motors are now coming around, Prucha said, adding that in-wheel motors are a question of when, not if.
Even if the negative issues are dealt with, the fact remains that in-wheel motors are not cheap. Prucha said the two in-wheel motors add around $50,000 to the $100,000 cost of a Brabus E-Class. Protean also made an all-electric E-Class, using four in-wheel motors, which would cost over $200,000. Still, that's the model that Brabus is potentially interested in selling, since some customers have expressed interest in buying such a car.
You can watch a video about Protean's motors right below. We rode in the prototype Ford F-150 fitted with in-wheel motors at last year's SAE World Congress and gotta admit, the E-Class looks like a lot more fun.
UPDATE: Prucha clarified to AutoblogGreen that the target price for the in-wheel motors, once production is ramped up in 18 months or two years, is $1,500 to $1,800 apiece. The prices quoted above are speculation about possible prices if Brabus would use the prototype motors.
DETROIT, April 23, 2012 /PRNewswire/ -- Protean Electric, the global leader in electric in-wheel motors, will showcase its award-winning Protean Drive™ system in a BRABUS Hybrid at the SAE 2012 World Congress April 24-26 at Cobo Center. The event will mark the BRABUS Hybrid's premier North American appearance.
In addition, Protean will host a press conference at 11 a.m. Tuesday in Booth#801. Protean Electric Chairman and CEO Bob Purcell will unveil the BRABUS Hybrid and announce several new global partners that will accelerate its in-wheel electric drive systems to market in high-volume production.
BRABUS, the highly acclaimed independent automobile tuner, chose Protean's electric in-wheel motors to power its "Technology Project Hybrid" based on the Mercedes-Benz E-Class. The BRABUS Hybrid vehicle is equipped with two Protean Drive™ wheel motors, which power the rear wheels, along with the vehicle's clean diesel engine.
Protean Drive™ is the most advanced in-wheel electric drive system for hybrid, plug-in hybrid and battery electric vehicles. Going well beyond performance, Protean Drive™ can improve fuel economy by up to 30 percent in a plug-in hybrid application.
Each Protean motor adds 80 kW (110 hp) and 800 Nm (590 ft-lbs) of peak torque, which, when combined with the 2.2-liter common-rail turbo-diesel engine, give the BRABUS Hybrid an acceleration of 0-100 km/hr (0-62 mph) in 7.4 seconds and 60-120 km/hr (37-75 mph) of 5.6 seconds.
BRABUS is known throughout the automotive sector for its discerning use of the finest technology to perfect the performance of its exclusive vehicles. The BRABUS Hybrid and Protean Drive™ offer elite automotive customers a practical, environmentally respectful solution without sacrificing performance and power.
"We're pleased to work with BRABUS to demonstrate what Protean's in-wheel electric drive can deliver to the world," Protean CEO Bob Purcell said. "Our in-wheel motors not only provide significant performance improvement, but do so in a very responsible way."
Protean Electric will present its findings, Paper Number 2012-01-1037, "Integrating In-Wheel Motors into Vehicles - Real World Experiences" at 8 a.m. April 25, in room 02-33 at Cobo Center.
For more information on Protean Electric, visit www.proteanelectric.com. For further details on BRABUS, go to www.brabus.com. For more information on SAE, visit www.sae.org.
About Protean: Protean Electric (www.proteanelectric.com) is a leading clean technology company that designs, develops and manufactures the Protean Drive™, a fully integrated, in-wheel motor, direct-drive solution. Protean Electric is strategically positioned to play a major role in the hybrid and electric vehicle market by offering a combination of packaging advantages, new vehicle design opportunities, performance benefits and cost savings. Protean is funded by Oak Investment Partners, a multistage venture capital firm and a lead investor in the next generation of enduring growth companies.