A British engineering firm has created a high-performance hybrid version of BMW's Mini Cooper: The PML Mini QED. It can get to 60 mph in 4.5 seconds and has a top speed of 150 mph. It does this using a small gasoline engine with four 160 horsepower electric motors — one on each wheel. The car has been designed to run for four hours of combined urban/extra urban driving, powered only by a battery and bank of ultra capacitors. Its range is between 200-250 miles in electric mode and about 930 miles when it taps its small conventional internal combustion engine (ICE) to re-charge its battery. In the hybrid mode, you’re looking at up to 80 miles per gallon.
“Until now, most electric vehicles have been little more than souped-up milk floats, limited by range and speed, with compromised performance.” Explains Martin Boughtwood of the engineering firm PML. “For those with a green conscience who also value an enhanced motoring experience, there is still something missing.
“Working in partnership with our customer, Synergy Innovations, we set out to demonstrate what our electric wheel technology is capable of. We simply took a standard BMW Mini One, discarded the engine, the disc brakes, the wheels, and the gearbox. These components were replaced by four of our electric wheels, a lithium polymer battery, a large ultra capacitor, a very small ICE with generator (so small it almost fits alongside the spare wheel), an energy management system and a sexy in-car display module.”
It seems to make sense. Why not put the motors where the wheels are? You eliminate the large engine, gearing and drivetrain so you get more space inside the car and you don’t need traditional brakes anymore, as all braking is performed by the wheel motors. In fact, those motors are actually very efficient, as they return almost all of the energy generated by the braking process back to the battery system. Plus, as PML has proven, this system is adaptable to existing vehicle chassis’.
All this, and it’s smart, too. Those four little electric motors include ABS which, by their nature, can also be applied to acceleration since the motor can smoothly control torque delivery in both cases. Flooring the brake or the accelerator just produces torque, so you get both the shortest possible stopping and acceleration times!
And, because they’re so smart, these wheels are in constant communication with each other, speaking with one another about
1000 times each second regarding how much torque they should share with each other. Should one wheel detect a slippery surface and take appropriate anti-skid actions, the other wheels are aware of this instantly and adopt an appropriate compensating strategy to keep the vehicle as stable as possible.
Not only does this motor-in-wheel approach eliminate the need for clumsy differential gears, it also means that – apart from wheel bearings – there are no parts to wear down in the drivetrain, so your horsepower stays as rated for the life of the vehicle. When you consider that each wheel develops 160 braking hp – that’s 640bhp in total – compared with the original Mini One’s 100bhp, you can imagine the performance upgrade. And don’t forget, those four electric wheels weigh less than half that of the original engine!
Still, there’s always the question of battery level. The QED uses its rear mounted ICE/generator to automatically top up the battery as its power diminishes, so when you arrive at your destination you can simply park the vehicle knowing that when you return the battery will be replenished. Or, you can plug it in to recharge it. Either way, you should never need to worry about battery capacity.
All in all, a brilliant approach that we hope we’ll see on our roads here in the U.S. soon.
