On a corner of the Renault Group stand at the recent Paris motor show stood the perfect use case for in-wheel motors. The company had stripped the body panels from its new Duo/Bento quadricycle – the replacement for the Twizy – and a large caged area between the rear wheels, incorporating the e-axle with an electric motor and driveshafts, was visible.
Without that, the Bento van version could have repurposed the space to vastly increase its luggage capacity. Or it could have been a usable boot for the Duo passenger model.
In the next hall, Japanese supplier THK had brought a concept vehicle created by famed ex-Nissan designer Shiro Nakamura that showcased exactly what could be achieved if you did fit in-wheel motors. Without an e-axle, the boot was deep and roomy in a way that few EVs have so far been. “Putting those functions in the corner of the car means the entire size [of the] automobile can be fully used for other purposes like roominess or comfort,” Nakamura told Autocar.
In-wheel motors have shown promise but commercial applications have been few and far between. They featured in the innovative Nissan Bladeglider sports car, which remained a concept. They were to have powered the doomed Lordstown electric pick-up, supplied by Slovakia’s Elaphe. The Dutch Lightyear solar car was also to have used Elaphe in-wheel motors before it too succumbed to financial realities.
So far, commercial uses have been confined mainly to electric bicycles or e-scooters but the as yet untapped promise for bigger vehicles is coming closer to reality.
Competitors to THK and Elaphe include the UK’s in-wheel motor champion, Protean Electric, which has just launched its fifth-generation version of the technology.
Meanwhile in Germany, start-up DeepDrive has received investment from BMW as well former Audi and Volvo technical head Peter Mertens, who is also an advisor.
Over in Korea, Hyundai Motor and Kia are working on the ‘Uni Wheel’ system that it calls a ‘paradigm-shifter’ for its ability to free up space, either for luggage or more batteries.
In-wheel motors are starting to move out of the prototype phase. Protean owner Bedeo has used them in a kit to convert classic Land Rover Defenders to electric. The company’s technology has also been used to create a plug-in hybrid version of the Fiat Ducato-based Trigano motorhome, with the existing rear wheels switched out for ones with in-wheel motor hubs that add electric drive and energy recovery. And in the US, a lorry trailer company is using them to harvest braking energy to feed new electric refrigerating units that replace diesel versions.
In China, state-owned car-making giant Dongfeng is testing a four-wheel-drive version of its Fengshen E70 saloon that uses Protean motors at the rear to create a second driven axle without a major overhaul to the car’s engineering. Protean’s factory in Tianjin, China, has the capacity to build 5000 motors annually.
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