First look: BMW reveals plug-in diesel super-coupe

BMW has revealed its first plug-in vehicle in the shape of a radical 2+2-seater super-coupe concept that is claimed to deliver both supercar performance and hybrid fuel economy.

Again dubbed the BMW Vision EfficientDynamics, the futuristic two-door emerges just over two weeks before it make its world debut at the Frankfurt motor show on September 15, alongside production versions of the mild-hybrid ActiveHybrid 7 (Series), full-hybrid X6 ActiveHybrid and 5 Series GT.

Obviously, the low-slung scissor-doored sportscar will be the headline act of the Munich manufacturer’s Frankfurt presentation, which is also expected to confirm first details of the so-called “near-zero emissions” Megacity compact car range being developed by BMW’s Project i eco-car division for release under the company’s electric vehicle (EV) sub-brand by around 2012.

As expected, the ground-breaking mid-engine four-seater showcar, which features an all-new aluminium spaceframe chassis draped with variable-transparency polycarbonate glass panels, applies maximum dynamic aggression to the first design study heralding BMW’s sustainable future mobility strategy.

Of course, BMW’s latest Vision EfficientDynamics concept, which follows the mild-hybrid diesel-electric X5 concept of the same name at Geneva last year, is far from a prototype of a production car.

It is what lurks within its wild, F1-inspired bodykit, which returns a staggeringly slippery aerodynamic drag co-efficient of 0.22Cd, that matters.

Claimed to offer “a realistic impression of the unique potential of BMW ActiveHybrid technology”, the Bavarian brand’s latest VED is not, as expected, a full-electric vehicle, but differs significantly from the petrol-electric drive systems in the ActiveHybrid 7 and ActiveHybrid X6, both of which employ BMW’s new twin-turbo 4.4-litre V8.

While the mild-hybrid 7 Series comprises one electric motor, the X6 full-hybrid can be driven on electric power alone thanks to a Toyota Prius-like two-mode parallel drive system with two electric motors, which was developed in conjunction with General Motors, Daimler and Chrysler.

The ActiveHybrid 7 is similar in concept to the Mercedes-Benz S400 Hybrid, while the X6 ActiveHybrid uses similar drive technology to the V6-powered Mercedes ML450 Hybrid, none of which are produced in right-hand drive.

Now, however, BMW’s newest VED – and potentially its eventual Megacity vehicle – advances a number of steps further, firstly by combining a plug-in recharging function as seen on full-electric vehicles like Nissan’s newly revealed Leaf and the Mitsubishi i-MiEV, which is expected to become Australia’s first EV late this year.

Second, the VED coupe all but confirms speculation that BMW will produce its first three-cylinder diesel by employing a turbocharged common-rail direct-injection 1.5-litre oil-burning triple, in this case fitted ahead of the rear axle.

Just as the overall design language is likely to form the basis of BMW's rumoured Z10 ED electric supercar by around 2015, expect the new three-cylinder diesel engine to make its production debut in the next-generation 1 Series due to emerge in 2011, before filtering upwards to the 3 Series.

With 120kW of power and 290Nm of torque on tap, the new BMW three-pot is claimed to set a new specific output record for a diesel engine of 80kW per litre, and is used to recharge its battery – as in GM/Holden’s ‘range-extending’ 2012 Volt plug-in hybrid.

Third, the all-wheel drive Project i coupe comprises two electric motors (a synchronous motor for the front axle and a full parallel drive motor at the rear), bringing total system output to 262kW and no less than 800Nm.

Finally, the Frankfurt VED is powered by a lithium-polymer battery pack that includes 98 cells, which makes it superior to the 7 Series hybrid’s lithium-ion battery and the X6 hybrid’s nickel metal hydride battery.

Aided by regenerative braking technology and an idle-stop function, the coupe has an electric-only range of 50km (which is slightly less than the Volt and many full EVs) and a total driving range of 700km.

The result is M-car performance and average fuel consumption that matches Toyota’s new Prius. BMW says the VED sportscar can sprint to 100km/h in 4.8 seconds on its way to an electronically limited top speed of 250km/h.

At the same time, its average EU fuel economy figure is 3.76L/100km, with CO2 emissions of 99 grams of CO2 per kilometre – or just 50g/km on the EU electricity mix cycle, including EV-only running.

Mounted between the engine and a dual-clutch automatic transmission, the rear motor develops a constant 25kW a maximum of 38kW to either provide electric assistance or a full EV mode.

The front-mounted synchronous motor offers a permanent output of 60kW and peak torque of 220Nm, with an extra 84kW available for up to 30 seconds and 104kW on hand for up to 10 seconds. Power is transmitted through a two-stage, single-speedreduced-ratio gearbox, providing the ability for the coupe to drive on just electric power, just diesel power, or an infinite combination of both power sources.

BMW says each of the 98 lithium-polymer cells has a capacity of 30 amp/hours, developing a continuous output of 600 amps at a voltage of 3.7 volts. For up to 30 seconds, each cell is able to develop a maximum output of 1200 amps.

BMW’s arrangement of the lithium-polymer cells generates a nominal voltageof 364 volts, with gross storage capacity of the battery being 10.8kW/h. Weighing in at just 85kg, the battery pack delivers 8.6kW/h to drive the car.

A maximum of just 2.5 hours is required to fully charge the battery via a conventional household power outlet, with higher voltage reducing the recharge time to just 44 minutes.

BMW’s arch-rival Mercedes-Benz has already announced it will fit an electric drive system to the front-end of its SLS supercar, which will also make its worldwide debut at Frankfurt, effectively turning it into an all-wheel drive.

The VED measures just 4.60 metres long, 1.90 metres wide and 1.24 metres high and features a number of Sauber F1 car-inspired air deflectors and guide vanes, including A-pillars that channel air around the roof, wing-profile tail-lights and a fully enclosed underbody, plus an active air-intake.

Fitted with huge 21-inch wheels wrapped in curiously narrow 195/55-section tyres, the coupe has an unladen kerb weight of 1395kg. Luggage capacity of the unusual mid-engined four-seater layout is listed at just 150 litres (enough for two golf bags, apparently), while total carrying capacity is 445kg.

The B-pillarless gullwing coupe’s interior features a ‘landscape’ design with LED-illuminated instruments and current BMW production car technologies like night vision and a (in this case three-dimensional) head-up display.

Finally, there is also a thermo-electric generator, which is claimed to develop up to 200 Watts byconverting thermal energy from exhaust emissions into electric power via the so-called Seebeck effect, integration of the electric power steering, idle-stop, active cruise control, navigation and trip computer systems, and additional features for the BMW ConnectedDrive telematics system.

Europe’s top-selling luxury brand, Audi, has confirmed it will also reveal its “top-down” EV strategy next month, most likely in the form of a plug-in version of the R8 super-coupe, leaving parent company Volkswagen to undertake a volume-selling small EV rollout.

Also joining the headlong rush towards hybrid luxury motoring at Frankfurt will be Toyota’s petrol-electric vehicle pioneer, Lexus, which will debut its first front-drive hatchback, hitherto codenamed C-Premium.

Like BMW’s Megacity vehicle, the new Lexus compact will be available with both conventional combustion engines and hybrid drive options. It has been confirmed for release in Australia in 2011, before the arrival of Daimler’s second-generation Smart ForTwo EV, which will also debut at Frankfurt.

“BMW Vision EfficientDynamics is therefore a particularly innovative renditionof hybrid technology BMW-style and at the same time offers a fascinating outlook into the future of BMW EfficientDynamics as an overall philosophy and a significant contribution to future-proof mobility,” says BMW.