BMW Megacity

BMW unveils electric car strategy

BMW has announced that its electric Megacity will form the technological basis of a family of hybrid and pure electric vehicles. The Megacity is a four-seater supermini set to launch in 2013. It’s bigger than the two-seater electric MiniE, but smaller than BMW’s 1 Series.

The Megacity, not to be confused with French manufacturer Aixam-Mega’s 40 mile range runabout Mega e-City, is the first BMW designed from the ground up as an electric vehicle. ‘It is just the first step in a series of electric vehicles from the BMW Group’, says Ian Robertson, the board member in charge of sales and marketing. He considers that by 2020 electric vehicles could form 30% of BMW sales – of which 12% would be pure electrics and the balance, hybrids.

The new Megacity will have an all-electric driveline with a single-speed electric motor. The rear-engined, rear-wheel-drive car is anticipated to have a range of between 100 and 150 miles after being charged for three hours. For the Megacity family, BMW is considering all forms of electric propulsion, from the hybrids we know today, to plug-in electric hybrids, and from pure electrics to range-extender cars like the Chevy Volt/Vauxhall Ampera with a small petrol engine on board to act as an electricity generator. The Megacity itself is likely to have a hybrid derivative.

The Megacity will also feature two major innovations: an aluminium chassis enclosing the wheels, suspension, battery and electric motor, and a separately-formed carbon fibre reinforced plastic body shell.

The Megacity project is designed to provide environmental transport for the growing number of urban conurbations with 10 million-plus populations, of which there were 83 in 1950 and 468 in 2007. The United Nations estimates that the 2010 urban population of 3.2 billion will have grown to 5 billion by 2030, when 60% of people will be city dwellers.

Ian Robertson continued: 'It will be sold under the BMW name but as a sub-brand, and we are currently deciding what that sub-brand will be called’. This is raising the hype ahead of the car’s appearance at the 2010 Paris Show – at which the Megacity is likely to be a star attraction.

The Megacity will benefit from the findings of two prototype field test programmes. The first is based on the two-seater, all-electric MiniE which is currently undergoing trials in the US and Europe. The second uses the four-seater Concept ActiveE – an electric-drive version of the BMW 1 Series – which will begin tests with 600 drivers starting in 2011. By the time the Megacity is introduced in 2013, its lithium-ion batteries, charging times and vehicle range will have been optimised by extensive field experience.

Ultra lightweight carbon fibre body

Carbon fibre is 30% lighter than aluminium and 50% lighter than steel. This weight saving, together with the lightweight aluminium chassis, helps to provide the range of up to 150 miles on a single charge. BMW is working with partner SB LiMotive on more energy-dense batteries. The range extender electric/petrol version will deliver a range of over 300 miles.

SGL Automotive Carbon Fibres L.L.C., a joint venture between BMW and the American SGL Group based in Washington State, will manufacture the ultra lightweight carbon fibre reinforced plastics to be used for the Megacity family. The fibres are extremely tear-resistant. When woven into a lattice structure and impregnated with resin they can produce a part that is stronger than steel.

Their strength is reflected in the crash-test performance of BMW’s carbon-fibre bodied prototypes. In front and rear-impact tests, energy is absorbed as the aluminium chassis crumples leaving the passenger compartment intact. Side impacts also protected the crash dummies to a greater degree than conventionally-bodied vehicles. Crash damage is potentially reparable by cutting out broken sections of carbon fibre and bonding in new ones.

Carbon-fibre bodies have a further feature which may not be such a great advantage to car manufacturers. They don’t corrode so the replacement cycle that car makers ultimately depend on for their new car sales is stretched interminably.

‘Project 442’

A beneficiary of Megacity technology is the ‘Project 442’ - a 450 hp concept electric supercar that is designed to take on the Mercedes SLR and Audi e-tron. It may be shown at the Paris Show in September 2010, but is more likely to be saved until next year’s Frankfurt Show – nearer its likely introduction date of 2013.

It will have an aluminium chassis and a carbon fibre reinforced body shell but, unlike its two competitors, it will be a four-seat, rear wheel drive car. It is likely to come in a hybrid version with a future six cylinder M3 engine positioned in the rear.