BMW Vision EfficientDynamics Concept

Debuting at the 2009 Frankfurt Motor Show, the BMW Vision EfficientDynamics is a sporty 2+2 seater that showcases the brand’s latest EfficientDynamics technologies, aimed at reducing fuel consumption while maintaining high levels of performance and handling.

Building on the downsizing principles, the plug- in full-hybrid powertrain adopts a 1.5 liter turbocharged diesel unit and two electric motors – one for each axle.

This layout delivers – when required – a total output of up to 356 hp, while at the same time achiving an average fuel consumption of 3.76 liters/100 kilometers (62.6 mpg) and CO2 emission of 99 g/km – 50 g/km in pure-electric mode.

The top speed is limited electronically to 155 mph, and the 0-100 km/h acceleration takes just 4.8 seconds.

The design features futuristic, almost-organic elements with the flowing forms of the interior and exterior that are closely interconnected. The drag coefficient is just 0.22.

The Vision EfficientDynamics also displays a number of innovations such as the layering construction technology, aluminum chassis and suspension, special polycarbonate glasses, lithium-polymer cells, a 3D head-up display and an advanced energy management system.

From the official Press Release:

Vision EfficientDynamics is the most comprehensive implementation of the EfficientDynamics philosophy seen so far.

The powertrain provides a top speed limited electronically to 155 mph, with acceleration to 100 km/h in 4.8 seconds. Average fuel consumption in the EU test cycle is 3.76 liters/100 kilometers, equal to 62.6 mpg, and the CO2 emission rating is 99 grams per kilometer.

When driving in the all-electric mode after charging the battery from a plug-in source the car’s emission rating is just 50 grams per kilometer.

The power and performance are made possible by combining a fuel-efficient 3-cylinder turbodiesel with one electric motor on each axle.

Overall system output is 356 horsepower, and peak torque is 590 lb-ft.

The special arrangement of the two motors and diesel engine allows all-wheel drive when driving in all-electric mode. The result is minimum power loss and a harmonious transmission of the power available under all conditions.

The body of this unique sports car is a result of lightweight technology and aerodynamic efficiency. In the design of the interior, the focus was on the driving experience and on transparent, hands-on technology and maximum reduction of weight.

Design

BMW Vision EfficientDynamics takes a new approach in its design and streamlining, the body and the interior clearly expressing the combination of efficiency and the sporting performance.

Following BMW’s design language, this concept car visualizes both highly efficient aerodynamics and intelligent lightweight construction.

In its design, BMW Vision EfficientDynamics differs from the usual low-emission car concepts.

The principle of “form follows function” is not just for the overall look of the car, but embraces each and every detail.

Measuring 48.8" (1,240 mm) in height and boasting a sweeping, arch-like roofline, BMW Vision EfficientDynamics "offers the slender silhouette of a classic Gran Turismo".

With the combustion engine fitted in front of the rear axle, the designers have created a very low front end, with the flow of air being further smoothened by active louvers in front of the radiator, which close completely when the need for cooling air is low.

An active air intake at the front guides air smoothly and as required into the car.

Numerous details in the design of the body are based on the know-how BMW has gained in Motorsport, a number of body elements serving as air deflectors and guide vanes.

Designed as ducts, for example, the A-pillars serve to channel the flow of air in the same way as the rear lights with their wing profile.

The floor of the car is fully covered from front to rear and from one side to the other, thus maintaining a smooth surface to avoid any air swirl liable to increase fuel consumption.

Slender openings around the front air dam guide the air flowing specifically into two closed ducts leading inside the front air dam to the wheel arches where the air comes out again through a very slim aperture at high speed, flowing just next to the outer wheel flanks.

This air jet rests on the front wheels like a curtain and is therefore referred to most appropriately as the “air curtain.” It provides a highly stabilizing effect.

To further optimize the aerodynamic qualities of the entire vehicle and keep rolling resistance to a minimum, BMW Vision EfficientDynamics comes with tires and wheels of quite unusual size on a sports car.

The tires measure 195/55, while large 21-inch wheels provide a contact surface on the road otherwise offered only by a much wider tire. In combination with the sophisticated axle geometry, this ensures agile driving behavior.

The extra-large wheel covers extending over part of the tire flanks add to the unique, very different look of BMW Vision EfficientDynamics from the side.

The blade profile integrated in the wheels serves furthermore to reduce the negative effect of the turning wheels on the overall aerodynamics of the car. In all, these features optimizing the aerodynamic qualities of the car give the BMW Vision EfficientDynamics concept car a very low drag factor (CX) of just 0.22.

In both exterior and interior design, BMW Vision EfficientDynamics stands out clearly as a strong spearhead in technology. Many components of the vehicle are presented in full view expressing the “transparent” character of the car as a powerful visual feature of lightweight technology.

The chassis and suspension of BMW Vision EfficientDynamics are made completely of aluminum; the roof and the outer skin on the doors are made almost completely of a special polycarbonate glass automatically darkening as a function of the light shining on the car.

Measuring 181.1" in length, 74.8" in width and 48.8" in height, this unique concept car offers ample space for up to four passengers and their luggage. Thanks to the consistent lightweight construction strategy applied on the car, curb weight is 3,076 lb, with the center of gravity remaining very low. In its power-to-weight ratio, the BMW Vision EfficientDynamics concept car is far superior to all other hybrid cars, achieving the same standard as extremely dynamic sports cars with a conventional combustion engine.

Carrying a maximum payload of 981 lb, this unique 2+2-seater is fully suited for everyday traffic. Luggage capacity of 5.3 cu ft, in turn, allows the driver and passengers to conveniently take along two golf bags. And to meet additional loading requirements the backrests of the two rear seats may be tilted down individually to provide extra storage space.

Interior Design

In the design of the interior, the layering technology provides a symbiosis of function and stylish shapes intentionally reduced to a minimum, consistently implementing and visualizing the lightweight principle also inside the car.

Specific components such as the central air vent not only serving to enhance motoring comfort but also acting as part of the cockpit, perform several functions in one.

This multi-functionality is then presented visibly within the car, the use of particularly sophisticated materials providing a highly attractive combination of innovation in technology and quality clear to the eye and the touch of the surface.

This interaction of lightweight construction and individual well-being also comes out clearly in the design of the controls and switches, with a leather band, for example, running round the aluminum gear selector lever on the center console.

Materials combining lightweight technology and all the qualities required are also to be admired all round the cockpit of BMW Vision EfficientDynamics, giving the car an unusually generous feeling of space for a 2+2-seater.

The body-contoured seats, for example, are made up of a kevlar shell, a backbone structure, and seat padding with personalized fillings. Clearly, this combination alone ensures comfort at a minimum weight.

The driver’s and front passenger’s seats are connected firmly to the center console to form a joint interior “landscape”, while the rear seats anchored on the floor would appear to be hovering in space.

Light Design

LED lights at both the front and rear end of BMW Vision EfficientDynamics provide a combination of the symbols typical of the brand – such as the distinctive look of the dual round headlights – and clear design language oriented towards trendsetting technology.

The rear lights are integrated also in their function into the design of the entire rear section, forming part of the rear air deflector and thus merging completely into the rear contour.

Extremely flat and compact, the rear lights are made up of innovative LED units forming a smooth and consistent red surface when not in use.

Only when used do the respective light chambers take on the appropriate color such as yellow on the direction indicators.

This innovative light technology also provides an intense symbiosis of the exterior and interior, again promoting and further refining the driving experience.

This is also why the ambient illumination of the interior comes with new features and qualities, the light sources within the passenger compartment being fed from the positioning lights at the side, the rear lights and the brake lights, thus changing the atmosphere created by the lights within the car as a function of driving conditions.

Integrated design

The optical impression conveyed by BMW Vision EfficientDynamics also results in other areas from the symbiosis of the exterior and interior, eliminating the conventional barriers between the two.

The lines within the interior, for example, continue on to the innovative design of the engine compartment lid, while in its shape the third brake light positioned higher up on the car follows the structure of the glass roof and tapers to the outside where the roofline moves down gently to the rear.

The doors on BMW Vision EfficientDynamics open up like bird’s wings, turning on pivots in the front roof column at the level of the side direction indicators.

Since the car has no B-pillars, the large door cutouts ensure convenient entry also to the rear seats.

The pivots on the doors also provide the base for the exterior mirrors, thus forming an ideal combination of function and aesthetic design.

The structure of the doors is also characterized by several layers of materials on top of one another.

Made up of three layers, the overall structure comprises the outer glass surface, an interim load-bearing layer, and the interior cover with its particularly smooth shapes and flowing forms clearly visible to the passengers.

The large glass surfaces extending far down on the body also provide a strong optical impression of the low seating position close to the road.

And at the same time a stable sidebar ensures the body stiffness and crash safety naturally required on every vehicle. Flowing to the inside at its central point, this safety element also serves as an armrest.

This interplay of the three layers also helping to minimize the weight of the car continues on the trim bar running along the door and extending out of the armrest, finally flowing into the outer door opener on its path from inside to outside.

Layering technology is also used on the displays in the instrument cluster and in the Head-Up Display developed to an even higher standard on BMW’s new concept car.

The Display now creates a powerful impression of three dimensions, at the same time providing the option to present various signals more in the front or more in the background, depending on their relevance and current driving conditions.

The Head-Up Display projects information important to the driver on to the windscreen. The gauge graphics are kept visible in the background while the latest information on route guidance or warning signals from BMW Night Vision, for example, are shown in the foreground.

The sequence in which such signals appear depends on the driving mode chosen by the driver, the display technology, again depending on the driver’s personal preference, enhancing a particularly sporting, a more comfort oriented, or an efficiency-based style of motoring.

Technical Features

The combustion engine is a new turbodiesel unit that makes its debut on this concept. Displacing 1.5 liters on three cylinders, the engine consistently follows the downsizing principle of using a relatively small engine combined with a turbocharger to reduce fuel consumption.

Through its compact dimensions, the 3-cylinder fits conveniently in front of the rear axle like in an agile mid-engine sports car, despite the two seats at the rear.

Fuel is injected by High Precision Direct Injection, and the turbocharger features variable intake geometry for maximum efficiency. Engine output is 163 hp with peak torque of 214 lb-ft.

The specific output of 109 hp per liter sets a new benchmark in diesel technology.

The power delivered by the turbodiesel is conveyed to the rear axle by means of a double-clutch transmission (DCT), that allows the driver to shift gears without the slightest interruption of power. BMW Vision EfficientDynamics features a newly-developed version of BMW’s DCT with six speeds for maximum efficiency and flexibility.

The combustion engine is supplemented by two electric motors. The overall layout combines a hybrid synchronous motor on the front axle and a full-hybrid system at the rear.

In this concept, the driver benefits from the efficiency of the electric motors over a far wider speed range than with a conventional hybrid car.

The rear axle comes with a second-generation full-hybrid system corresponding to the technology in the BMW ActiveHybrid 7 production model.

The compact electric motor positioned between the diesel engine and the DCT outputs a consistent 33 horsepower and is able to reach a peak of up to 51 hp.

Maximum torque for the rear electric motor is 214 lb-ft, the power, either supporting the diesel engine or in all-electric motoring. When coasting or applying the brakes, the electric motor acts as a generator and feeds electric power to the lithium-polymer battery in the car. The electric energy developed in this way is therefore captured without any additional consumption of fuel through the principle of Brake Energy Regeneration. Energy wasted on the brakes of a conventional car is thus saved within the new power system for subsequent use in driving the car.

A second electric motor acts on the front axle. This engine, a hybrid synchronous motor, offers continuous output of 80 horsepower and peak torque of 162 lb-ft. Extra power of 112 horsepower is available for a period of up to 30 seconds, and, for a 10-second “burst,” the electric motor is able to develop 139 horsepower. The power is transmitted through a 2-stage, single-speed reduction gearbox.

BMW Vision EfficientDynamics is able to run completely under electric power, with the power of the turbodiesel engine alone, or through an infinite combination of the three power sources.

Depending on driving conditions, the two electric motors may be used both for accelerating and for regenerating energy when applying the brakes and while coasting.

When accelerating, the electric motors help to boost the car for greater performance. For a short time, such as in passing maneuvers, the cumulative maximum output of all three engines increases to 356 hp, with maximum torque generated by the three engines reaching 590 lb-ft.

The energy cells featured in BMW Vision EfficientDynamics are housed in a chassis element running from front to rear through the middle of the car.

The front unit is the lithium-polymer complex, an ongoing development of the lithium-ion battery. Overall, BMW Vision EfficientDynamics comes with a total of 98 lithium-polymer cells, each offering a capacity of 30 amp/hours and developing continuous output of 600 Amps at a voltage of 3.7 V. For a period of 30 seconds, each cell is even able to develop maximum output of 1,200 Amps.

Serial arrangement of the lithium-polymer cells serves to generate nominal voltage of 364 volts, the gross storage capacity of the battery is 10.8 kW/h. With an unusually high discharge capacity of 80 percent, the battery delivers 8.6 kW/h for driving the car.

This superior performance comes on overall weight of the entire energy storage system of just 187 lb. Through their optimum dimensions tailored to the features of the car, the lithium-polymer cells, together with energy management system, reduces the thermal load acting on the battery so that there is no need for active cooling.

Brake Energy Regeneration captures electric power generated while driving.

A further option is to connect the lithium-polymer cells to a conventional power socket using a plug-in connector in the front-right wing of the car.

Connected to a standard EU power outlet (220 V, 16 Amps), the system requires a maximum of 2 ½ hours to fully charge the lithium-polymer cells.

And wherever a power source with higher voltage and amperage (380 V, 32 Amps) is available, the charge time is an even shorter 44 minutes.

In addition to electrical energy storage, BMW Vision EfficientDynamics comes with a conventional fuel tank at the rear end of the central chassis tunnel, offering a capacity of 6.6 gallons.

Running on diesel fuel alone, BMW Vision EfficientDynamics is able to cover a distance of approximately 400 miles with its combustion engine. Benefitting from an extra range of up to 31 miles in the all-electric mode, the car offers an overall range of approximately 431 miles.

Applying the criteria of the EU test cycle, BMW Vision EfficientDynamics offers average fuel consumption equal to 62.6 mpg. CO2 emissions, in turn, are 99 grams per kilometer.

The energy management system uses information gathered by the sensors of the driver assistance units fitted in the car.

Data provided, for example, by the rain sensor or Active Cruise Control with its Stop & Go function as well as by the navigation system, and subsequently evaluated by the central control unit, offers an overview of current and upcoming driving conditions. Then, evaluating such data, the on-board computer is able to forecast driving conditions on the stretch of road immediately ahead.

Should the high-performance central computer establish, for example, that the driver is about to take the motorway, the power used for running the cooling system is reduced for a certain period in advance, on the assumption that the short increase in coolant temperature resulting from such an energy-saving measure will quickly be set off by the higher speed of the car on the motorway. Another example of such pre-conditioning is the regeneration of energy from the air conditioning, from Electronic Power Steering and the Brake Assistant.

(Source: BMW)