POWERTRAIN
package, protect and keep the weight down for an e-bike that could be ridden until the rider tired (around two hours), made it a challenging project but one that technical director Sylvain Rubio relished. “It was a dream project really,” says Rubio. “We had a clean sheet of paper and around 1,000 hours of engineering time to dedicate.” The EB-01 is the result and is
reckoned to be a true tour de force for e-bikes. A range of 80 miles and a charge time of less than 90 minutes mean it is ideally suited for a rider to head out for a couple of hours of hard riding and still be able to pedal home if needed. Too powerful and too
fast for the road – it will easily reach 60mph and out-gun most motorbikes off the line – the staggering performance is testament to the novel design from a team that had no two- wheeled experience before starting.
CNC OVER CARBON Whilst many would consider pure carbon for the frame, Rubio opted for a hybrid aluminium carbon construction. The reasons were manifold. The frame could be CNC machined without expensive tooling and thanks to Swindon Powertrain’s in-house 7-axis CNC capability, it could employ complex machined
❝ We had a clean sheet of paper and around 1,000 hours of engineering time to dedicate
Hybrid construction for the frame
parts and produce them quickly. The frame also acts as the casing for the 1.75-kilowatt-hour lithium ion battery, eliminating unnecessary weight and enabling the team to get very close to its 40kg target. This packaging solution not only saved weight but also ensured the design could incorporate air cooling for the motor and also house the 9-speed sequential gearbox. To better understand how to
create electric powertrains, the team developed in-house the inverter, controllers and dashboard, acquiring software and hardware knowledge that has been instrumental in its subsequent ‘crate’ EV HPD product. “It was crucial that the project
be a valuable training and learning tool but as engineers we wanted it to be original and fun,” adds Rubio. “We learnt a lot about packaging that has enabled us to get the HPD powertrain to weigh less than 50kg and that includes lubricants, the brushless permanent magnet motor, transmission, open differential and a metre of cabling. With a package size of 441mm x 384mm x 228mm, HPD is also the highest power/volume unit for automotive applications on sale. The bike definitely served its purpose.”
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