Tech breakthrough for electric vehicles
by Zachary Shahan
In-wheel electric motors come to market next year
The holy grail of electric vehicle technology is in-wheel electric motors, which put power directly to the street and eliminate a host of other parts. In-wheel electric motor maker Protean claims that by next year, production of their revolutionary product will begin.
Weighing just 68 pounds, but capable of delivering 100 horsepower and 735 ft-lbs of torque per wheel, the Protean in-wheel electric motor eliminates things like driveshafts, differentials, and transmissions. That reduces the cost and complexity of electric drivetrain setups, and drops a whole lot of weight as well. Mercedes tuner Brabus has used two Protean motors in their diesel-electric hybrid (above) to great effect.
Each motor can be controlled independently, allowing for more control in dicey situations. The motors reclaim up to 85% of the kinetic energy via regenerative braking. They can also be retrofitted to existing vehicles fairly easily.
With production scheduled for next year, I am left wondering what automakers are signed up for this awesome tech? Or will Protean sell them as stand-alone units directly to customers? So many possibilities… what will come of it all?
Protean Electric’s CEO is Bob Purcell, the “father” of the EV-1 (the world’s first modern electric vehicle) at his former employer, General Motors. The company states that the new drive system can improve vehicle fuel economy, add torque and increase power. Direct-drive, in-wheel motors require no gearboxes, driveshafts or differentials, allowing far greater flexibility to vehicle designers, while substantially reducing drivetrain energy losses. Less energy is wasted during either acceleration or regenerative braking-- resulting in more battery energy being available to propel the vehicle.
The Protean system can increase fuel economy by over 30% percent depending on the battery size and driving cycle. It is powerful enough to be the only source for traction on a variety of vehicles. Its ease of integration simplifies the adoption of hybrid and electrified powertrains across a broad range of vehicles.
The in-wheel motors have the highest torque and power density of any of today’s leading electric propulsion systems. Each can deliver 81 kW (110 hp), weighs only 31 kg (68 lbs.) and is sized to fit within the space of a conventional 18- to 24-inch road wheel (see illustration above). Their superior regenerative braking capability increases driving range up to 30% while reducing battery size / cost. Each has a built-in inverter, control electronics and software. They can constitute a retrofit application for existing fleets as well as new vehicles, without needing a separate motor power electronics module to be fitted.
In summary, this breakthrough technology creates a common system for HEV, PHEV and EV vehicles on the same manufacturing platform.
Publ. here 6.5.2013