Insider's view: underneath the skin of BMW's new concept

BMW Vision EfficientDynamics concept

It's a strange time for motorists that really like cars. The sportscar as we know it is arguably coming to the end of its time, what with the increased need to use less fuel. However, if BMW's latest concept car is an indicator for the future, enthusiasts won't feel too hard done by. In a nutshell, the Vision EfficientDynamics is capable of BMW M3 levels of performance, yet returns fuel consumption and emissions significantly better than anything else BMW currently produces. Have we got your attention?

A numbers game

The bare figures are worth poring over before we go under the skin of the concept. To satisfy drivers, the Vision accelerates from 0-62mph in just 4.8 seconds and its top speed is limited to 155mph. Those numbers are identical to the current M3 Coupé's and are mostly thanks to a total system output of up to 351bhp and 590lb.ft of torque - and the car's relatively low weight of 1,395kg (260kg lighter than the M3). Perhaps more impressive though are 99g/km of CO₂ and 75.1mpg on the combined cycle, results that are better than most current production cars.

How is this possible?

Well we mentioned the low weight already, which is down to extensive use of carbon fibre and other exotic lightweight materials, but the powertrain is a little special too. Sitting ahead of the rear axle is an all-new three-cylinder turbodiesel engine of 1.5-litre capacity. It features the latest generation of fuel injection and turbocharger technology to produce 161bhp and 214lb.ft of torque - figures on a par with the current BMW 320d's four-cylinder unit. It's mated to a six-speed dual-clutch gearbox, which transmits power to the rear wheels. All sounds pretty normal so far, right?

Sitting between the gearbox and engine at the rear is a compact electric motor/generator. It can produce as much as 51bhp and 214lb.ft of torque and it can be used with or without the engine running. Under braking or deceleration this motor acts as a generator of electricity, to charge the car's bank of lithium ion batteries.

Taking energy from those batteries is another electric motor mounted on the car's front axle. Maximum output from this motor can reach 162lb.ft and 139bhp. Depending on a variety of conditions, the car can use one or both motors and the engine in any permutation. Hence for full acceleration both motors and the engine would be employed, but for town driving it's likely that just one of the motors will be in operation for zero emissions driving.

The all-electric range of the concept is estimated at 31 miles, so some journeys won't require the diesel engine at all, and the batteries can be charged via a conventional domestic power source too. Beginning to make sense?

So why the fancy body work?

Obviously its first job is to draw the crowds in, but BMW has apparently put a huge amount of technical know-how into the exterior of the concept car. With the engine mounted at the rear, it was possible to use a low front end to reduce drag, a situation that is further improved by active louvers in the front radiator grille - they close up when cooling air is not required.

What you can't see is the completely flat under floor, which smoothens out air flow further, while narrow openings in the front bumper divert air out through apertures by the wheels, acting as an 'air curtain' around them and significantly improving the aerodynamics. Even the front A-pillars and lights have a part to play in managing the airflow around the car, with the aim being low drag without any loss in stability.

What next?

If you want to see the Vision concept up close any time soon you need to get yourself along to the Frankfurt Show. Doors open to the public on September 17th and the Vision EfficientDynamics concept will be the star of BMW's stand. You shouldn't be surprised to hear that a production version is not very likely in the near future, but many of the concept's features will appear in showroom models. There are ActiveHybrid versions of the 7 Series and X6 about to go into production for instance and we have it on good authority that the Vision's three-cylinder turbodiesel engine will be under a BMW bonnet sooner rather than later.

Shane O' Donoghue