BMW Efficient Dynamics Concept, 2009

BMW EfficientDynamics Concept, 2009

The BMW Vision concept car clearly demonstrates that the Efficient Dynamics 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 ActiveHybrid components with an extremely economical combustion engine, and outstanding aerodynamic qualities.

Two electric motors for full-hybrid drive.
The combustion engine is supplemented by two electric motors. Consistently applying the BMW Active Hybrid 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 Active Hybrid 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 Efficient Dynamics 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 Efficient Dynamics 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 Efficient Dynamics 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 Efficient Dynamics 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 Efficient Dynamics 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 Efficient Dynamics 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 Efficient Dynamics 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 Efficient Dynamics 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 Efficient Dynamics development strategy in this unique concept car.

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.

The instrument panel is deliberately padded only where technical components have to be appropriately covered, thus making an important contribution to passenger safety in the event of a collision. The instrument cluster played a fundamental role right from the start in the design process, serving as the starting point for all surfaces within the interior and thus creating a particularly powerful rendition of that driver orientation typical of BMW.


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