The second BMW X6 Concept shown at the 2007 Frankfurt Motor Show demonstrates BMW’s ActiveHybrid technology, which BMW says is superior to conventional hybrid vehicles in terms of driving dynamics – looking at the assortment of hybrids on the market today we can safely say that’s not too far from the truth. BMW rates an ActiveHybrid car as having 20% better consumption and emissions compared to a comparable car with conventional drivetrain technology.
The BMW Concept X6 ActiveHybrid combines a combustion engine and two electric motors. Keeping to their promise of a sporty driving experience, BMW says despite electric motors being used BMW retains the appropriate touch-based and acoustic feedback never seen before on a hybrid vehicle.
The combustion engine and two electric motors are connected to each other via three planetary gearsets, allowing a power split between the combustion engine and electric motors in two ranges. At any time, the car can be powered by either only the combustion engine or only the electric motors. The Concept X6 ActiveHybrid also uses an ECVT electrical continuously variable transmission and is able to adjust power between the combustion engine and the electric motors in two ranges – one for low speeds and one for high speeds. Power to the wheels also go through a fixed ratios as BMW thinks this is very important for the whole driving experience – the feeling of swapping cogs.
The electric motors can also be run in reverse to harvest wasted power during braking. This power is used to charge a high-volt energy storage unit. BMW is already doing something like this with Brake Energy Regeneration, something that’s appearing on conventional combustion engine BMWs in the European market.
In power split drive mode, one of the electric motors acts as a generator, converting some of the engine’s power into electrical current to charge the capacitors. The power can also be channeled into the second electric motor. This second electric motor gets power from either the first electric motor or the capacitor and generates mechanical power for the output drive shaft.
The ActiveHybrid hybrid drive system is BMW’s variant of the Global Hybrid Cooperation hybrid system, a joint project between BMW, General Motors and DaimlerChrysler to develop next generation hybrid drive systems.
More photos after the jump.