The new BMW i3 electric vehicle has been officially unveiled in simultaneous presentations in London, New York and Beijing.
The BMW i3 is powered by an electric motor rated at 170hp with 250Nm of torque.
Unlike conventional internal combustion engines, maximum torque is available instantly, and this leads to an impressive 0-62mph time of just 7.2 seconds. Top speed is 93mph.
The i3 has an everyday range of 80-100 miles, which compares favourably with the findings of a government report that suggested the average daily commute clocks in at 13.1 miles each way.
A ‘range extender’ version, equipped with a 650cc two-cylinder petrol engine to charge the lithium-ion battery, is also available, and extends the useful range by 180 miles on one tank of fuel.
The electric motor consumes 0.21kW/h per mile and, when taking low cost charging tariffs into consideration, equates to a diesel engine achieving over 400mpg.
To make town driving even easier, there’s a single-pedal feature. While there are both brake and accelerator pedals, when the driver takes their foot off the accelerator pedal, the electric motor switches to generator mode. This not only recharges the battery, but also creates a load similar to that of applying the brakes. The system works automatically at town speeds, but at high speeds the car will coast to conserve momentum and therefore improve efficiency.
BMW say the system can increase the range by up to 20%, and it’s clever enough to know to activate the brake lights when regenerative braking is in effect to avoid nasty incidents.
Power is stored in a lithium-ion battery pack, made up of eight modules, each with 12 individual cells. Combined, the pack – which weighs 230kg and is stored in the flat floor – produces 360 volts and 22kW/h, and is designed to last for the vehicle’s entire life time.
BMW is unusual in not offering a separate battery lease for the i3. So confident are they of the battery pack’s reliability that the initial purchase price of the i3 includes the battery.
Several innovative ideas are employed to maintain the battery’s condition. To maintain an optimum battery temperature of 20 degrees C, the air conditioning coolant passes through the pack, cooling when necessary or warming prior to operation.
Individual battery cells can be replaced should a fault develop, and an eight-year 100,000 mile battery warranty covers against premature failure.
In the UK, the BMW i3 uses AC Fast Charging, with a 7.4kW charge from zero to 80% taking three hours. A BMW i Wallbox can be purchased from Schneider Electric, with the installation managed by BMW. The box costs £315 including installation, after a 75% government grant.
Charging via a standard household socket using the supplied cable takes eight to 10 hours. However, the fastest charge option is via a 50kW DC Rapid Charging outlet, which can provide an 80% charge in just 30 minutes.
As a BMW, the i3 is of course rear wheel-drive, but unlike other BMWs there is no transmission tunnel to encroach on interior space.
Kerb weight is just 1,195kg, thanks to a multitude of weight-saving measures. The drive motor and associated electronics are directly connected, alleviating the need for 1.5kg of cabling. Aluminium suspension components are used where possible, as are hollow drive shafts, light-weight aluminium wheels, aluminium bolts and screws instead of steel, and even a honeycomb structure for the windscreen wiper.
The light weight isn’t just to improve efficiency. Agility has also been a keen target for BMW’s engineers, and the i3 uses MacPherson strut front suspension and a five-link rear axle mounted directly to the drive module.
The i3 boasts a tight turning circle of 9.86m and a quick-responding steering set-up with just 2.5 turns lock-to-lock.
The BMW i3 is available in four guises – Standard, Loft, Lodge and Suite – each with a distinct interior character.
The BMW i3 costs £25,680 after a £5,000 government grant. The i3 Range Extender version costs £28,830. Both are of course exempt from the London Congestion Charge and qualify for zero road fund licence.
Order books open in August, with the official launch set for 16th November 2013.