The BMW Vision EfficientDynamicsSeptember 11, 2009
looking supercar is the BMW Vision EfficientDynamics which has M3 performance but
emissions of just 99g/km and economy of 75 mpg.
car has a 1.5-litre three-cylinder turbo diesel engine and two electric motors,
producing 356hp and a huge 800Nm of torque.
If the car
drives under just electric power, which it can do for 31 miles, CO2 emissions
(tank to wheel) are 0g/km. Running in hybrid mode, the emissions drop to just
51g/km CO2 – and that’s after taking the source of electricity generation into
Vision EfficientDynamics highlights a number of technologies that will appear
on BMWs of the near future. BMW’s Air Curtain system is fitted, which channels
air through a front valance with the air exiting ahead of the front wheel. The
Air Curtain system’s exiting air flow effectively deflects air from entering
the wheel arch and causing turbulence thus improving all round performance.
of the BMW Vision EfficientDynamics also takes styling cues from the marque’s
involvement in Formula 1. The ‘exo-skeletal’ appearance of elements of the
design mean the vehicle cuts through the air with the least possible
resistance. The drag co-efficient is 0.22 – the lowest figure of any BMW road
car. The subtle folds of the bodywork create downforce without the need to have
three-cylinder turbocharged diesel engine is capable of recording peak power of
163hp, a new record in terms of output per litre at 109hp, and a peak torque of
290Nm. Mounted transversely and ahead of the rear axle, the diesel engine can
be the sole power source for the vehicle or it can work in conjunction with the
electric drive. Alternatively the diesel engine can be used to charge the
electric drive battery pack.
drivetrain features two electric motors – one on each axle. At lower speeds
just the electric drive mode functions. The rear axle motor can produce up to
38kW of power and 290Nm of torque, while the second axle motor is capable of
60kW and 220Nm of torque.
overboost function allows the driver to top this up to 84kW for a 30 second
boost and 104kW for a 10 second power enhancer. When taking all three power
sources into account these figures equate to a car that records a peak power of
356hp and torque of 800Nm. Power is transmitted to the road via an enhanced
version of BMW’s existing seven-speed Double Clutch Transmission.
Vision EfficientDynamics has a range of 31 miles when driving only on electric
mode. Combined with the three-cylinder diesel engine this extends to a total
possible distance between fill-ups and charges of 431 miles. Using a
conventional domestic power source at 220 V would result in the vehicle being
fully recharged after 2.5 hours. Access to a slightly more powerful 380 V sees
the charge time drop to 44 minutes.
hybrid vehicles that use existing vehicle architecture and then add a hybrid
drivetrain, the BMW Vision EfficientDynamics isn’t penalised by weight. A V8 or
larger capacity engine that would be the norm for a supercar has been
substituted by a compact three-cylinder engine and two electric motors. This is
fitted to an aluminium chassis to further save weight. The result of this is
that the vehicle tips the scales at just 1,395kgs.
customer demand for larger alloy wheels with wider tyres is at odds with
aerodynamic and rolling resistance targets. However, BMW engineers working with
Michelin developed a solution to this. The contact patch of the BMW Vision
EfficientDynamics has effectively been turned 90 degrees by virtue of
specifying larger diameter wheel rims. Larger, but thinner tyres result in the
same percentage of rubber being in contact with the road, but the cross section
of the tyre as a whole is smaller making for less rolling resistance and
greater aerodynamic efficiency.
renowned for using lightweight materials as part of its EfficientDynamics
strategy and this concept car is no different. The chassis and suspension are
made entirely from aluminium while the roof and the outer skin of the doors are
made of a lightweight polycarbonate glass. This material also comes with
special properties that allow the glass to darken in sunlight to keep the cabin
temperature at the desired level.
Vision EfficientDynamics also showcases BMW’s Thermo Electric Generator
currently fitted to the exhaust system of test cars and being developed for
production. This works on the principle of the Seebeck effect to generate an
electrical current courtesy of the temperature change between two metal based
semi-conductors. This system alone generates enough charge to power some of the
is a 3D Head-up and a new incarnation of iDrive with a touchpad screen. The
vehicle has a 2+2 configuration and of course with the rear seats folded the
BMW Vision EfficientDynamics even has room for two sets of golf clubs that can
be stowed in the 150-litre luggage area.
interested, here’s how BMW worked out the emissions taking energy generation
into account. If the electric power comes from a European power station
emitting an average of approximately 290g CO2 / kWh, electric consumption by
the car of 17.5kWh/100km means well to wheel emissions are 50.75g/km (17.5 x
290 ÷ 100 = 50.75).
Vision EfficientDynamics is the centrepiece of the BMW stand at the Frankfurt