BMW Efficient Dynamics Makes More Power

Drive concept BMW X5 research car

BMW Shaping the Future Part 10

Press Release

BMW Efficient Dynamics Makes More Power

Up to 1,000 Nm Torque on 15% Less Fuel

Much more power on far less fuel.
Efficient use of kinetic energy.
First BMW research vehicle opening up new horizons.

Much more power on far less fuel: Precisely this apparent contradiction in terms is solved by a special BMW Group research project. Focusing on the philosophy of efficient dynamics, BMW Group engineers seek to eliminate inefficient driving situations with high fuel consumption. The problem is that stop & go traffic and acceleration, in particular, consume a lot of fuel even with the very best combustion engine. A further point is that application of the brakes converts valuable kinetic energy into useless heat. A further general point is that the combustion engine is able to develop only a fraction of its nominal output at low speeds (e.g. only about 15-20% of its maximum output at 1,000 rpm). One solution is to integrate an electric motor between the combustion engine and the transmission, helping to boost the engine when accelerating.

Click photo for larger size Applying this concept, a BMW X5 test vehicle is able to develop start-up torque of up to 1,000 Nm. Then, as soon as the combustion engine has reached its midrange speed and therefore develops enough power, the electric motor is cut back. Working as a team, the electric motor and combustion engine provide a response never seen before, boosting engine torque to an unprecedented level above all at low speeds. The energy required for the electric motor is delivered by an electrostatic high-performance energy reservoir free of wear. Made up of double-layer capacitors, this reservoir is able to store and build up kinetic energy while driving, that is the energy generated when the driver applies the brakes or when the car is in overrun. This keeps the system independent of any external sources of energy and even provides energy not just for the electric motor, but also for the onboard network. The second big advantage of this system is the significant reduction of fuel consumption, comparative test runs showing that this technology is able to save about 15 percent fuel simply because the combustion engine is efficiently supported by the electric motor at precisely the right point. Such extra power in the acceleration phase thus not only helps the driver, but also serves to protect the environment and save money. The bottom line, therefore, is that BMW Group engineers, working on this research project, are opening up an enormous potential in improving not only the dynamic performance but also the environmental compatibility of the modern automobile.

Source: Text and photos courtesy BMW AG