2015 BMW i8 hybrid sports car details revealed

The new i3 electric hatch isn’t the only i-badged BMW we’ll be seeing this year; another is a new i8 plug-in hybrid sports car that will not only top the i range of cars but also serve as BMW’s flagship. We were given our first taste of the i8 four years ago, when BMW rolled out its Vision EfficientDynamics concept at the 2009 Frankfurt Auto Show.

Since then we’ve seen the concept’s design revised, a convertible Spyder unveiled, and numerous prototype versions testing around the globe. Soon, we’ll see the production i8 revealed, as BMW has confirmed the car’s appearance at the 2013 Frankfurt Auto Show in just over a month.

In a lead up to its debut, BMW has provided details on the car’s technology and specifications. As we already know, the i8 features a sophisticated drivetrain that pairs a turbocharged and direct-injected 1.5-litre three-cylinder engine with an electric motor.

The engine is used to drive the rear wheels via a six-speed automatic transmission while the electric motor powers the front pair via an integrated two-stage auto ‘box. However, both power sources can work together to form a through-the-road all-wheel-drive setup.

The engine develops a peak 170kW while the electric motor rates in at 96kW. Maximum system output is 266kW and 570Nm, which is said to be enough for 0-100km/h acceleration in under 4.5 seconds -- and that, friends, is Porsche 911 Carrera territory. Like most BMWs, top speed of the i8 will be governed to 250km/h.

On electric power alone, top speed is limited to 120km/h and BMW predicts a driving range of 35km. On a mix of electric-only and hybrid modes, BMW says i8 owners can expect a fuel economy of around 2.5L/100km for the Euro-measured combined cycle.

BATTERY PACK

Running down the centre of the floor is an “energy tunnel” that houses a lithium-ion battery. It has a liquid cooling system and can be recharged at home using an ordinary power socket. In the U.S., a full recharge takes approximately 3.5 hours from a conventional 120-volt, 12-amp household socket. Importantly, charging can also be done on the run using regenerative forces.

DRIVETRAIN

The i8's sophisticated drivetrain is housed in what BMW calls the “Drive” module, a lightweight aluminium structure that also houses the electronic control units, suspension components, and structural and crash protection components. The suspension consists of a double-track control arm front axle and a five-link rear axle, all made of aluminium. Electromechanical power steering and electronically operated dampers are also fitted. The wheels are forged aluminium and measure in at 20 inches across.

WEIGHT AND BALANCE

By attaching all of these technical components to the Drive module, the i8 benefits from a very low centre of gravity (the lowest of any BMW) and a perfect 50:50 weight distribution.

Mounted on top is the “Life” module, which is essentially the passenger cell. This section is comprised primarily of carbon fibre-reinforced plastic in order to keep strength and rigidity high but weight low. The savings from this design offset the additional weight of the electric motor and battery, giving the i8 a curb weight of less than 3,285 pounds. If it had stuck with conventional steel, BMW says the i8 would weigh around 50 per cent more.

DESIGN

Other innovations for the i8 include the use of chemically-hardened glass similar to Gorilla Glass used for smartphones. Some of the glass on the i8 is just 0.7 of a millimetre thick, yet it still provides the sound-deadening one would expect in a luxury car. The exterior of the i8 stretches close to 4694mm in length, has a width of 1951mm and a height of just 1280mm. The car has a drag coefficient (Cd value) of just 0.26 and inside there is generous 2+2 seating.

TECHNOLOGY

For the driver, selection of power sources is done intelligently via computer control. BMW’s typical linear acceleration is said to be maintained even at higher speeds since the interplay between the two power sources absorbs any power flow interruptions when shifting gears.

Using the gear selector, the driver can either select position D for full automatic mode or can switch to SPORT mode. SPORT mode offers manual gear selection and at the same time switches to very sporty drive and suspension settings. Power is also split between the front and rear axles to aid handling. On entering a corner, for example, the power split is biased towards the rear wheels to improve turning precision.

The Driving Experience Control switch on the centre console offers a choice of two settings: COMFORT and ECO PRO. On starting, COMFORT mode is activated, which offers a balance between sporty performance and fuel efficiency. ECO PRO minimizes power loss through items like the air conditioner and maximises regenerative forces. The driving range in the COMFORT setting is around 499km but hitting ECO PRO can boost this by around 20 per cent.

That's all BMW is telling us for now, but we should have the full details soon. Following its debut at the 2013 Frankfurt Auto Show early next month, the i8 will hit European showrooms later in the year and should be on sale in the U.S. next spring.

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