Power cycles: how ebike systems take the strain
The latest generation of ebikes prove that a small amount of electric assistance can go a long way in urban transport. Chris Pickering reports.
Ever since the invention of motorised transport, people have been searching for smarter ways to get around the city. In recent years, we’ve seen proposals for autonomous pods, air taxis and even a network of tunnels that could allow self-driving cars to travel underground at speeds of up to 150mph. But could the answer lie with a modern take on a far more traditional form of transport?
Electrically assisted bicycles, better known as ebikes, have been around for over 20 years. In Europe, they remain the best-selling form of electric vehicle, despite the much-publicised uptake of electric cars. They now cover just about every genre of cycling, from full-suspension mountain bikes capable of taking on the toughest trails to cargo bikes for inner-city couriers.
“The ebike is one of the most efficient forms of transport,” explained Tamara Winograd, vice president for marketing and communications at Bosch eBike Systems. “They’re the fastest means of transport in the city for journeys under 10km; they relieve city traffic complications and reduce the burden on the environment by avoiding queues and reaching destinations faster in a manner that is healthier and more sustainable – all while enjoying the freedom and fun of riding.”
The German engineering giant has been working on ebike technology since 2009. During that time, there have been significant strides in the development of batteries, drive units and control systems. Although fundamentally still a bicycle – under UK law you must be actively pedalling for the electrical assistance to engage above walking speed – they have evolved into sophisticated machines in their own right.
Bosch now offers functions including fully automatic gear shifting, smartphone connectivity and even ABS to make life with an ebike simpler, safer and more rewarding. Don’t assume that electric assistance is ‘cheating’, though. Studies have confirmed that those riding ebikes for leisure generally apply a similar amount of physical exertion to riders on unassisted bicycles, it’s just that they are able to travel further and faster in the process.
For commuters, it’s more about covering greater distances without breaking a sweat. Top of the range systems, such as Bosch’s Cargo Line drive unit can multiply your pedal effort by up to 400 per cent, while the unit’s maximum torque of 85Nm is more than that produced by the engine of an original 998cc Mini.
“Range, reliability and personalisation around power options are key requirements for any ebiker,” said Winograd. “Those relying on an ebike for transport will be particularly focussed on range (this is often a worry for new ebikers) and speed of charging. A commuter cyclist also wants a versatile drive system offering a natural riding sensation for smooth pedalling that’s compact and powerful.”
The company’s flagship PowerTube 750 lithium-ion battery provides 750Wh of energy storage. It’s connected via a CAN network to Bosch’s own battery management system (BMS), which protects the pack from extreme temperatures, overcharging, and excessive discharge.
The BMS system is just the start of the onboard intelligence on a modern ebike. Bosch’s Nyon cycle computer uses smartphone connectivity and its own WiFi connection to integrate functions like route planning and performance monitoring. It can tell you whether a planned destination can be reached before the battery runs out, based on the current state of charge and the level of assistance that’s been selected. There’s even a lock function, which disables the motor when the display unit is removed.
With its recently launched Smart System, Bosch allows users to tailor the operation of the bike’s drive unit via a smartphone app. It also features over the air (OTA) updates that will enable new apps and features to be offered in the future.
This could just be the start when it comes to ebike connectivity, Winograd points out: “If we look further into the future, the ebike will become part of the Internet of Things (IoT), like refrigerators, washing machines or lawnmowers. This lays the foundation for bike-to-X communication; it will allow ebikes to connect with other vehicles and infrastructure, increasing road safety.”
According to Bosch, ebikers typically use their bikes two to three times more frequently than conventional cyclists, travelling significantly further in the process. The bikes average approximately 7Wh/km of energy consumption, which is around 20 times less than a typical electric car. Factor in the far lower environmental impact of manufacturing and recycling ebikes, and they have the potential to significantly lower emissions in urban areas.
“Taken over its entire service life, an ebike has an average CO2 footprint of about 14g/km,” said Winograd. “If we consider the pure use phase and the emissions caused by electricity consumption, the average CO2 value is 2 to 5g/km, depending on the energy mix. In comparison, according to the German Federal Environment Agency, a car accounts for around 150g per passenger, per kilometre (g/Pkm) and public transport between 60 and 80g/Pkm CO2.”
The bikes themselves are only part of the equation. Dedicated charging stations aren’t generally required as the batteries are removable and small enough to charge at home or in the office. However, there are other infrastructure considerations that need to be considered if the full potential of ebikes is to be unlocked, such as dedicated cycle lanes and bike parking facilities.
“Travel infrastructure for bicycles is still behind in many cities,” Winograd continued. “To transform urban transport towards more sustainability and life-worthiness, cyclists must become an equal focus in transport planning. For decades it has been strongly oriented towards cars. Well-developed bicycle infrastructure increases safety and will encourage even more people to switch to ebikes or bicycles.”
Of course, ebikes are unlikely to solve all the problems associated with inner city transport. But crucially, they are a sustainable and comparatively affordable option that could tempt many away from their cars. With a little bit of electrical assistance, it may yet be the 200-year-old concept of the bicycle that wins the race for urban transport.