BMW has finally given us our first official, undisguised look at its futuristic, all-electric city car. For now the i3 is still labeled a concept, but this car is much more complete than the MegaCity concept that preceded it. The four-passenger i3 concept is perhaps the most advanced take on electric cars yet, and draws on BMW's experience with a fleet of 600 Mini E and 1000 BMW ActiveE electric cars. Unlike those cars, however, which were traditional cars converted to electric drive, the i3 was developed from the ground up to accommodate electric propulsion.
The i3 is built around a new chassis concept called LifeDrive, which divides the vehicle into sections for Life, the passenger compartment, and Drive, the powertrain and battery. For the i3, the bottom half of the car is the Drive section, and is made mostly of lightweight aluminum; the Life passenger compartment sits on top and is built from carbon-fiber reinforced plastic (CFRP). Employing these lightweight materials keeps the i3's weight down to just 2750 pounds. The Nissan Leaf, for comparison, tips the scales at 3366 pounds.
BMW says that CFRP is as strong as but 50 percent lighter than steel. The entire Life CFRP shell weighs less than 220 pounds. Better yet, it never rusts and reportedly offers better protection than steel in a crash. CFRP only forms the Life sections' shell, however, as replaceable plastic panels form the i3's true bodywork. The Life section slots on top of the Drive chassis and is attached with strong adhesives and four bolts.
The i3's electric motor was developed by BMW because the company wanted tight control over the feel and performance of its powertrains. It is said to be 40 percent smaller than the similar motor used in the Mini E. It is rated at 170 hp and 184 lb-ft of torque, and has a single-speed transmission. The motor is located directly above the rear axle, making the i3 a rear-wheel-drive vehicle and also keeping the front-rear weight balance even.
The motor is fed by a liquid-cooled lithium-ion battery pack that is mounted under the floor of the passenger compartment. This means there is no intrusion or transmission tunnel in the cabin, and also helps keep the i3's center of gravity low for better handling and stability. BMW wouldn't specify the battery's storage capacity.
Though the maximum range per charge is rated at 140 miles, BMW admits real-world i3 mileage will be between 80 and 100 miles -- approximately on par with the range offered by the Nissan Leaf. Data from the Mini E trials taught BMW that a battery range of 74 to 93 miles would satisfy 90 percent of all drivers. The i3 concept can reach 62 mph in 7.9 seconds, and its top speed is limited to 93 mph because BMW says higher velocities would drain the battery too quickly.
A full charge is said to take just six hours via a standard European outlet, while an optional fast-charger yields an 80-percent charge in just one hour. Charge times on American 120-volt outlets will likely be longer.
Futuristic Styling and Compact Dimensions
The i3 concept is a five door hatchback design that is approximately the same length as a Mini Cooper hatchback, at 151.4 inches long, but as wide as a Ford Fusion sedan (79.2 inches). Access to the interior is easy because the rear doors open suicide-style, and there is no B-pillar dividing the opening. Inside are two bench seats, with seating for a total of four people. Thanks to the lack of a transmission tunnel, the benches span the entire width of the car. The hatch offers just 7.1 cubic feet of cargo space, barely more than a Mazda MX-5 roadster, but the rear seats can fold for more room. There also is a small front trunk for holding the charging cable and other small tidbits.
The design is most notable for having fully transparent doors: aside from a small reinforcement bar, the entire door is made from glass. The roof is likewise made from glass, with some small reinforcement bars. Standard BMW design cues have been tweaked to fit the eco-friendly vision of the i3, including a BMW roundel badge with an electric-blue ring, and the brand's traditional kidney grille cutouts accented in electric blue. LED head- and taillights are meant to recall the lighting designs of other BMW products. The entire exterior wears combinations of Silver Flow, gloss-black, and Stream Blue colors, which combine for a seriously futuristic look.
There is also a new take on the controversial Hofmeister kink that pervaded BMW car design for years: converging silver plastic lines on the i3's C-pillar are called the "stream flow" and are intended to visualize the car's aerodynamic shape. Indeed, the entire undertray of the car is flat to reduce drag, while specially shaped wheel arches and a rear diffuser further improve aerodynamic performance. That also explains the aluminum wheels, which measure 19 inches in diameter but wear tires as skinny as 150 to 175 millimeters wide. BMW says the tall, narrow wheels reduce drag, have less rolling resistance, and don't protrude into the cabin as much as typical wheels.
Unique Interior
Color combinations inside consist of Porcelain White surfaces, Mocha Brown leather, blue stitching, and Stream Blue illumination. There is no center console or shifter, as all the vehicle controls are mounted on the steering column or dashboard. There's a cup holder in front of the heating vent, meaning drinks can be kept warm by running the heater or chilled by running the air conditioning. An assortment of touch-screen displays spans much of the dashboard, allowing both driver and passenger to monitor vehicle charging status, use the navigation and entertainment systems, or operate the climate control.
Unsurprisingly, the i3 concept has accelerator and brake pedals, but BMW thinks you'll only need the former. Lifting off the accelerator engages regenerative braking, which slows the car enough to account for about 75 percent of braking in city driving. BMW says that most people should be able to commute using just the accelerator; the i3's friction brakes should only be required for hard stops or holding the car stationary.
Other technologies to make urban driving easier begin with Proactive Front Protection, which uses a camera mounted beneath the rear-view mirror constantly scans for cars and pedestrians. It sounds a warning if the driver is about to collide with something, and at speeds up to 37 mph, Proactive Front Protection can automatically apply the brakes to prevent a collision.
The i3 will also use an evolution of BMW's Parking Assistant, which requires no human interaction to parallel-park the vehicle. The system can assume control of the steering, brakes, accelerator, and transmission to provide fully automated parking. The most intriguing of these technologies, however, is Traffic Jam Assistant. Like adaptive cruise control, the system automatically maintains a safe following distance from other vehicles, and can slow the i3 to a halt if traffic completely stops. But unlike other such systems, Traffic Jam Assistant can also steer the i3 within traffic lanes at speeds up to 25 mph. BMW suggests that you could make a phone call or check your email from behind the wheel -- so long as you keep one hand on the steering wheel so the system stays engaged.
Other Technologies
In case the i3's promised range isn't enough for drivers, the ECO PRO mode can help improve mileage by up to 20 percent. The driving mode adjusts the accelerator response and climate controls, and limits the car's top speed to 74 mph. A further ECO PRO+ mode disables things like the heated seats, heated mirrors, and daytime running lights, while limiting top speed to 56 mph. ECO PRO+ is meant only a last resort to help i3 drivers get home on their last few electrons.
BMW will also make available an optional gasoline-powered range extender, called REx. The engine powers a small generator that maintains the battery charge so that the i3 can continue driving after its initial battery charge has been depleted. BMW wouldn't divulge any details on REx, but it will be available for customers who really want the additional range.
BMW plans to launch mobile applications for smartphones and tablet computers, allowing i3 owners to monitor their cars remotely. The apps will allow owners to lock or unlock the car, sound the horn, illuminate the headlights, or check the vehicle's charging status. A CarFinder function uses GPS to locate the vehicle within 1500 meters.
Coming Soon -- Maybe
The i3 is at least two years away from going on sale: BMW says the car will go into production in 2013 and will launch "by the end of" 2013. There are many things that the company either hasn't determined or isn't willing to share. We still have no idea of the battery pack's storage capacity, how much the i3 might cost, or when it might be sold in the U.S. market.
BMW stresses that the i3 is a show car, so some of the stylistic flourishes will be toned down before the car enters production. The full-glass doors and transparent roof are likely to be nixed; BMW even showed us a prototype CFRP mold for the i3's roof panel. But the basic technology seems solid, and it seems unlikely the i3's basic technical specifications will change between now and 2013.
The i3 concept will make its first public debut at the Frankfurt Motor Show in September.
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