BMW officially launched the i3 electric car at the 2013 Frankfurt Motor Show and also showed a prototype of the plug-in hybrid sports car, the i8. This variant of the i8, which was first seen as a concept four years ago, is due to enter production later this year. The latest development of the i8 features a lightweight, carbon-fiber-reinforced plastic (CFRP) aerodynamic body with a plug in hybrid powertrain.
Two major elements make up the i8's BMW i LifeDrive architecture. The aluminum Drive module includes the internal-combustion engine, electric motor, battery, power electronics, and chassis components with structural and crash functions. The passenger cell is the Life module. BMW claims this architecture provides a very low center of gravity and close to 50/50 weight distribution.
The i8 will measure 4689 mm (184.6 in) long, 1942 mm (76.5 in) wide, and 1293 mm (50.9 in) tall and sits on a wheelbase 2800 mm (110.2 in) long. BMW claims a drag co-efficient (Cd) of 0.26. Unladen mass is claimed to be less than 1490 kg (3285 lb).
The car's doors are made from a CFRP inner structure with an aluminum outer skin, which is said to reduce mass by 50% compared with a conventional door. A magnesium instrument-panel support reduces mass by around 30% compared with the BMW X6. Reduction in the number of components reduces mass a further 10%.
BMW claims a world first for using chemically hardened glass, which is said to be around 50% lighter than traditional laminated glass. This is used for the partition between the passenger compartment and boot, and it's made from two 0.7 mm (0.03 in) thick sheets of glass with an acoustic sheet sandwiched between them.
It is the first BMW to be fitted with a high-performance three-cylinder, turbocharged gasoline engine. The engine combines a range of technologies including direct injection, BMW’s TwinPower turbocharger technology, and the companies Valvetronic variable-valve control, which helps to eliminate the need for a throttle.
From a capacity of 1499 cm³, the engine produces 170 kW (228 hp) and peak torque of 250 N·m (184 lb·ft). Drive is transmitted to the rear wheels via a six-speed automatic gearbox. BMW says that using the EU test cycle for plug-in hybrids, the i8 will offer fuel consumption of less than 2.5 L/100 km, with CO2 emissions of less than 59 g/km.
The hybrid drivetrain also includes a synchronous motor that drives the front wheels. This motor produces 96 kW with peak torque of 250 N·m. BMW claims a self-magnetizing effect for the motor similar to that of a switch reluctance motor. It is said the advantage is it ensures the electromechanical field generated when current is applied remains stable even at high rpm.
The motor can be used in conjunction with the internal-combustion engine to provide a power boost, delivering 0-100 km/h (0-62 mph) acceleration in around 4.5 s, or can power the vehicle itself, with a range of up to 35 km (22 mi). Electrical power is stored in a lithium-ion battery mounted under the floor. The battery pack is liquid-cooled and can be charged from a domestic power point, wall box, or public charging point.
The driver can adjust the drive and suspension settings to their own requirements.