The Brake Energy Regeneration system uses a beefed up alternator and battery to recycle previously lost energy, in turn saving fuel. This is achieved as the alternator reduces drag on the engine by only engaging when required to charge the battery, whereas a traditional alternator is always pulling power from the engine. Some models will also feature an automatic start-stop function to save fuel. The system automatically switches the engine off when the vehicle is stationary and restarts when the driver engages the clutch pedal before pulling away in a normal manner. A third fuel saving device is the electronic power steering system that only draws power when assistance is required, such as turning a corner.
Gasoline powered models will also benefit from BMW's latest high-precision fuel injection features, which on the 320i, for example, will lift output from 150 to 170hp. The 320d, on the other hand, is expected to debut BMW’s super efficient 400Nm four-cylinder diesel.