The coupe and convertible will be available with the xDrive system mated to a diesel engine.
BMW is adding all-wheel drive variants with diesel engines to the 6-series in the form of the 640d xDrive Coupe and Convertible. The cars will make their premiere at the Geneva Motor Show next month and be in the showrooms by the spring. The 3.0-liter diesel engine is characterized by TwinPower Turbo technology producing 313hp and 465lb-ft of torque helping the car to accelerate from 0-62 mph in 5.2 seconds.
The xDrive system distributes power between the front and rear wheels as the situation demands. It is controlled by an electronic control unit which links xDrive up with the DSC (Dynamic Stability Control) to ensure optimal traction, safety, and handling in all weather and road conditions. BMW boasts that the engine is boosted by the latest multi-stage turbocharging that is fed off a common-rail direct injection whose piezo injectors work with maximum pressure of 2,000 bar. The engine's weight has been reduced by producing the crankcase from aluminum.
The multi-stage turbocharging technology responds precisely to the demands of different driving situations. At low revs a smaller turbocharger is activated, its low moment of inertia allowing it to go to work extremely rapidly. The compressed air from this small charger is sent directly to the combustion chambers via a bypass line. As the air no longer flows through the large charger, loss-free development of charge pressure is assured. Only when the driver asks for more power do the electronics prompt the bypass unit to bring the larger turbo into play.
Added to which, variable turbine geometry for the smaller of the two turbos optimizes the effectiveness of the turbocharging system in responding to the power requirement at any one time. An eight-speed Sports automatic gearbox connects the engine with the wheels. In the ECO PRO mode (likewise standard) the power reserves ensure efficient driving style at low engine speeds. EfficientDynamics package of technology and Driving Experience Control come as standard. ECO PRO mode carries out adjustments to the engine management, accelerator mapping and shift characteristics of the automatic gearbox.