BMW Efficient Dynamics Concept, 2009
The BMW Vision concept car clearly demonstrates that the EfficientDynamics objectives are fully compatible when applied to a sports car. Conceived as a 2+2-seater with plug-in full-hybrid technology, the unique car combines the performance of a BMW M vehicle with a standard of fuel efficiency and emission management that exceeds even the current levels achieved by the latest small cars. The outstanding result is made possible by the combination of BMW Active Hybrid components with an extremely economical combustion engine, and outstanding aerodynamic qualities.
BMW EfficientDynamics Concept is the result of a "clean-sheet" development process to ensure that the correct achievements were made in the areas of efficiency, driving pleasure, technology, and emotional design. BMW EfficientDynamics Concept 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. CO2 emission management is even more outstanding when driving in the all-electric mode after charging the battery from a plug-in source: Taking all emissions in the generation of electricity into account, as prescribed by the EU formula, the car's emission rating is just 50 grams per kilometer.
BMW EfficientDynamics Concept
The power and performance are made possible by combining a fuel-efficient 3-cylinder turbodiesel with one electric motor on each axle. The intelligent combination of these units, together with precisely controlled energy management, simultaneously enhances the dynamic performance and the efficiency of the car. 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.
BMW EfficientDynamics Concept for the first time conveys the dynamic look of a BMW sports car to a hybrid vehicle. Developed with decades of experience in Motorsport, the body of this unique sports car is a result of intelligent lightweight technology and aerodynamic efficiency. In the design of the interior, the focus was likewise on both the fascinating driving experience and, in particular, on transparent, hands-on technology and maximum reduction of weight.
Turbodiesel engine with unprecedented specific output.
The combustion engine is a cutting-edge turbodiesel featured for the first time in the BMW EfficientDynamics Concept car. 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 the latest generation of 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). This advanced transmission technology, which already offers a particularly dynamic driving experience in BMW's M3 and Z4 Roadster, allows the driver to shift gears without the slightest interruption of power. BMW EfficientDynamics Concept features a newly-developed version of BMW's DCT with six speeds for maximum efficiency and flexibility.
Two electric motors for full-hybrid drive.
The combustion engine is supplemented by two electric motors. Consistently applying the BMW ActiveHybrid philosophy, development engineers followed the principle of "Best of Hybrid," choosing the optimum combination of a hybrid synchronous motor on the front axle and a full-hybrid system at the rear.
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.
The 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 EfficientDynamics Concept 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. This principle ensures efficient energy management, with the charge status of the lithium-polymer battery constantly remaining within the optimum range. When accelerating, the electric motors help to boost the car for even greater performance, ensuring immediate response and a significant reduction in fuel consumption. 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 lithium-polymer battery for electrical energy.
The energy cells featured in BMW EfficientDynamics Concept 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 EfficientDynamics Concept 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.
The 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. A further advantage is that through their optimum dimensions tailored to the specific qualities and features of the car, the lithium-polymer cells, together with the operating strategy chosen with a concept of "forward looking" energy management, reduces the thermal load acting on the battery to such an extent that there is no need for active cooling.
The Plug-in solution: convenient charging of the electric power system from a conventional power socket.
Brake Energy Regeneration captures electric power generated while driving without additional fuel consumption, which is subsequently used to supply power to the electric motors and on-board network. A further option is to connect the lithium-polymer cells to a conventional power socket for a simple and efficient charge process, 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.
The Fuel efficiency and emission management opening new dimensions in hybrid technology.
The power delivered by the two electric motors and single diesel 3-cylinder engine gives the BMW EfficientDynamics Concept a level of performance superior to anything provided so far by a hybrid vehicle. Acceleration from a standstill to 100 km/h, for example, comes in just 4.8 seconds and the car could exceed its electronically-limited 155 mph top speed.
The fuel efficiency and emission management now reach a standard only achieved, if at all, by far less powerful small cars conceived for city traffic and short distances. Applying the criteria of the EU test cycle, BMW EfficientDynamics Concept offers average fuel consumption equal to 62.6 mpg. CO2 emissions, in turn, are 99 grams per kilometer. These consumption and emission figures are measured on a consistent internal power balance, meaning that the batteries and storage media for electrical energy maintain the same charge level throughout the entire test cycle (with the same level at the beginning and end) and are charged while driving only by the car's on-board systems.
As a plug-in hybrid, BMW EfficientDynamics Concept is able to cover the entire drive cycle for measuring fuel consumption also with its combustion engine completely switched off. Then, to subsequently charge the lithium-polymer cells to the same status as when setting off, all the driver has to do is connect the car to an external power grid. To determine the consumption of electric power, the only requirement is to compare the charge level of the battery before and after the test cycle. Applying this measurement process, the BMW EfficientDynamics Concept car consumes 17.5 kW/h per 100 kilometers, equal to a CO2 emission rating of just 50 grams per kilometer in the EU test cycle.
To determine the total volume of CO2 emissions when driving in the all-electric mode, new legal standards for measuring the level of fuel consumption are currently being prepared for hybrid and electric cars with a plug-in power supply. Applying this calculation method, the CO2 emission ratings generated by BMW EfficientDynamics Concept are reduced further to just one-third of the original figure of 99 grams per kilometer. Clearly, this significant reduction of emissions opens up a new dimension in BMW's EfficientDynamics development strategy in this unique concept car.
Aerodynamic qualities reflecting BMW's Motorsport experience.
BMW EfficientDynamics Concept also takes a new approach in its design and streamlining, the body and the interior clearly expressing the unique combination of supreme efficiency and the sporting performance of the brand. Following BMW's design language, this concept car visualizes both highly efficient aerodynamics and intelligent lightweight construction.
In its design, BMW EfficientDynamics Concept 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" in height and boasting a sweeping, arch-like roofline, BMW EfficientDynamics Concept offers the slender silhouette of a classic Gran Turismo. With the combustion engine fitted in front of the rear axle, the designers have succeeded in giving the car 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. This efficient function follows in the footsteps of the active air flap control already used as a feature of BMW EfficientDynamics in some of BMW's current production models. As a further highlight, BMW EfficientDynamics Concept guides air smoothly and exactly as required into the car through an active air intake at the front.
Overall vehicle concept for a drag coefficient of just 0.22.
Technological look as a strong impression of intelligent lightweight construction.
In both exterior and interior design, BMW EfficientDynamics Concept 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 EfficientDynamics Concept 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.
Emotional design through sculptural shapes and layering technology.
Reflecting the innovative drive concept of this unique car, the design of BMW EfficientDynamics Concept likewise takes a new approach in combining functional progress with a most powerful emotional impact.
This has been achieved through the close cooperation of BMW's Design and Technical Development Divisions starting at an early point and continuing consistently throughout the entire development process. The result is a brand-new vehicle architecture with the drive components as well as the body and interior elements perfectly coordinated and matched to one another with maximum flexibility and individual style.
A fully integrated design philosophy also provided new options in using harmonized design principles connecting the exterior and the interior and providing an interacting effect between the two areas.
Interior: innovative lightweight construction and unprecedented orientation to the driver.
Innovative layering technology provides an unprecedented 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.
Innovative light technology: providing clear signals to the outside and offering soothing ambient illumination inside in a unique symbiosis.
LED lights at both the front and rear end of BMW EfficientDynamics Concept provide an innovative combination of the symbols typical of the brand and clear design language oriented towards trendsetting technology. The distinctive look of the dual round headlights characteristic of a BMW is emphasized in particular by the use of LED 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.
Overhead doors for convenient access to all seats.
The doors on BMW EfficientDynamics Concept 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 and the optical and functional symbiosis of the interior and exterior this technology is able to offer. 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 fl owing forms clearly visible to the passengers, layering technology again, therefore, opening up new perspectives.
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.
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