BMW will begin applying its start-stop and regenerative braking systems—now used in 1- and 5-Series BMW models (earlier post)—to MINI hatch models later this year, with resulting improved performance and efficiency. The MINI Cooper D—already the most fuel efficient of the line—will offer fuel consumption of 3.9 liters/100km (60 mpg US) and CO2 emissions of 104 g/km.
BMW’s Brake Energy Regeneration uses an Intelligent Alternator Control (IAC) and an Absorbent Glass Mat lead-acid battery for energy storage. The IAC 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.
Additionally, the energy generated by the engine on over-run (under braking or descending a hill) was previously wasted. Now this lost energy is utilized by the IAC to charge the battery.
The Auto Start-Stop Function, available with manual transmission cars, automatically switches the engine off when the vehicle is stationary and the driver puts the car into neutral. To restart, the driver only need engage the clutch again before pulling away in the normal manner. The system may be de-activated at the touch of a button when not required.
Switch Point Display aids drivers of manual transmission MINIs in selecting the most economical gear in which to drive. The engine management system analyses speed, road situation and accelerator pedal position and based on this data calculates optimum gearing. The ideal gear is then displayed by number in the cockpit display.
BMW said that even prior to the application of the start-stop and regenerative braking systems, MINI had reduced CO2 output per vehicle by an average 14% last year, compared to an industry average of 0.3%.