This past year, we called out 10 of 2013′s most-promising new technologies, and alongside stuff such as super plastics, fancy batteries, and precipitation-dodging headlights sat the ever-production-elusive electric hub motor. Specifically, we spoke to a Protean Electric design that actually appeared as if it might see the light of day; it turns out that we were on the right track. The Michigan-based company has announced that it will begin producing hub motors next year in China, and that it is building an electric driveline for an EV to be sold by Volkswagen’s Chinese partner, FAW-Volkswagen.
The new EV, to be based on the FAW-Volkswagen New Bora compact sedan, will utilize a pair of rear-mounted Protean hub motors. Each wheel’s unit makes 100 horsepower, and all of the control electronics are packaged inside the motors. Of course, the motors’ most important stat is weight—the more poundage, the more unsprung weight vehicle engineers must contend with—and Protean claims each one weighs 75 pounds. That’s a lot of extra unsprung weight to wreak havoc on ride and handling, but Protean previously conducted tests with Lotus Engineering that proved regular folks wouldn’t notice any difference.
We remain skeptical, but not as skeptical as we are about the benefits of installing hub motors in an entry-level vehicle like the Bora. The hoopla surrounding hub motors—the reason design students the world over keep doodling them into their designs—has everything to do with enhanced vehicle packaging. Moving the driveline to the wheels frees up real estate for passengers, cargo, safety cages, and so on, not to mention adding untold flexibility to vehicle architectures.
The FAW-VW Bora is not a car that will benefit from any of this—it already has a hood and an engine compartment where, we assume, a regular electric motor would fit nicely. What will become of that space? Protean doesn’t say, but we wouldn’t put batteries there—especially in light of Tesla’s compromised battery snafus (and that automaker’s energy packs are mounted between the wheels!). Also, rear-wheel-bound motors raise questions, too; in regular form, the Bora, which is related to the previous-generation Jetta, is front-drive. One would assume FAW-VW will need to redesign the rear suspension to handle drive torque, and it’ll probably have to make similarly extensive changes to the front end, too.
Now, it isn’t totally fair to rain on Protean’s parade, because, after all, manufacturers need to start using hub motors at some point in their designs. Developing hub motors for more widespread use will require semi-experimental fitments such as FAW-VW’s before the technology’s true potential can be realized in applications with more to gain from it. Take, for example, a hydrogen fuel-cell vehicle; there’s a significant amount of powertrain-related gear to locate in the car, including a bulky pressurized hydrogen tank, an electricity-generating fuel-cell stack, and, of course, the electric drive motor(s). Moving that last bit to the wheels would free up much-needed space. For now, Protean’s work is being employed by a car that doesn’t need it and won’t sell well in China, where EVs are, if anything, even less popular than they are here.
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