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BMW Concept X6 ActiveHybrid - Research in Energy

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BMW Concept X6 ActiveHybrid
Research in Energy
Worlds first Sports Activity Coupe
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Optimised use of energy and superior power in every situation.
The innovative power transmission  featured by BMW Concept X6 ActiveHybrid combines two compact, high-performance electric motors with a transmission using fixed transmission ratios. These drive systems are connected to one another by three planetary gearsets allowing a power split covering the drive forces of the combustion engine and the electric motors in two transmission ranges and thus ensuring a level of variability quite impos-si­ble on a conventional hybrid drivetrain thanks to the combination of the two drive sources able to provide optimum power and maximum efficiency under all driving conditions and power requirements from the driver.  The system referred to on account of its two operating modes as the two-mode active transmission also comprises a high-performance battery, power electronics with an integrated inverter module, and the cables required.
The two-mode active transmission is based on an ECVT electrical continu-ously variable transmission. The two operating modes, one of which has been optimised for low, the other for high speeds, are supplemented by fixed transmission ratios.
The two power-split ECVT sections allow the drivetrain to run at continu-ously variable speeds and ensure full, highly efficient hybrid functions throughout the complete operating range of the car, the innovative system in BMW Concept X6 ActiveHybrid thus serving to reduce fuel consumption by up to 20 per cent compared with a comparable BMW running on a combustion engine alone.
Given the two-mode system, the electric motors are furthermore very compact in their dimensions, facilitating integration into the overall vehicle as well as a minimum increase in  weight, which is  lower in the case of BMW Concept X6 ActiveHybrid than with conventional hybrid cars offering comparable power.  BMW Concept X6 ActiveHybrid can be driven on electric power only, on the combustion engine alone, or with a combination of both power units. Depending on driving conditions, the electric motors may also be used for both accelerating and regenerative application of the brakes, in which case the brake forces generated when coasting and when applying the brakes flowi to the high-volt energy storage unit to provide an increase in electric power.
This energy subsequently available for further use need not be generated by the combustion engine and is therefore available virtually free of charge.
Already using this principle in a similar manner on production cars featuring Brake Energy Regeneration, BMW is able to ensure efficient energy management and maintain the battery at a high charge level. On the road, the support provided by the electric motors in this way referred to as “boosting” serves, first, to give the car incomparable spontaneity and a direct response and, second, to significantly reduce fuel consumption.


BMW ActiveHybrid comes in where conventional hybrid drive reaches its limit.
Conventional hybrid systems allow efficient motoring only in relatively small or medium-sized vehicles at relatively low speeds. This is because most of the power coming from the combustion engine has to be conveyed most of the time via the electrical path of the transmission and because of the use of a high level of electric power. A car with enhanced dynamics, performance and running speeds would therefore require a larger combustion engine calling for less efficient, larger and heavier  electric motors.
In the power split drive mode, also referred to as the output branched concept, one of the two electric motors acts as a generator, converting some of the engine’s power into electrical current subsequently fed to the battery or the second electric motor. The second electric motor then converts such power coming from the first electric motor or from the battery back into mechanical power for the output drive shaft on the transmission.
Two-mode technology varies the balance of electrical and mechanical energy on the respective paths for optimum efficiency.
A further point is that a conventional hybrid drive system does not come with fixed mechanical transmission ratios, which would serve to optimise fuel consumption. Instead, conventional hybrid drivetrains use a continuously variable transmission, with the disadvantage that the actual requirement for performance and load feedback from the car are separated from one another, thus failing to provide a dynamic driving impression.
The two-mode active transmission, by contrast, overcomes and eliminates the disadvantages of a conventional hybrid drivetrain. It reduces the share of power flowing through the electrical branch of the transmission throughout a broad range of transmission ratios. Through its power split in two transmission ranges, the two-mode active transmission therefore provides the energy of both electric motors in an ideal form tailored to current driving conditions.


BMW ActiveHybrid: the result of years of research.
The principle of the two-mode active transmission in BMW Concept X6 ActiveHybrid forms a significant milestone in BMW’s ActiveHybrid strategy, fulfilling the demands made by a broad range of customers looking for a dynamic, economical and responsible form of motoring.
To reach this goal BMW pursues a clear-cut “Best of Hybrid”  strategy enabling use of the optimum components under a modular principle within a wide range of different vehicle concepts planned for the future. Parallel to the Global Hybrid Cooperation, the BMW Group has therefore entered into yet another joint venture with DaimlerChrysler, developing components for hybrid drive in the luxury performance saloon.  BMW started to develop hybrid drive many years ago, long before the foundation of the Global Hybrid Cooperation. Indeed, BMW tested the electric drivetrain as early as in the late 1980s, for example in the BMW E1. And the BMW Group has been conducting research on hybrid technology and its various options for more than 15 years, making this technology and the results already obtained a firm part of the BMW X5 EfficientDynamics development strategy.
In the meantime the BMW Group has presented several hybrid vehicle concepts, starting with a hybrid car in 1995 based on the BMW 518i.
In particular, the outstanding potential of this drive technology has been proven in the BMW X5 EfficientDynamics presented in 2003 and the BMW Concept X3 EfficientDynamics shown to the world in 2005.
Introducing BMW Concept X6 ActiveHybrid, BMW is proudly presenting the highest degree of maturity in hybrid technology seen so far. Indeed, this technology offers everything it takes to combine extremely efficient motoring with that Sheer Driving Pleasure so typical of BMW.
A clear sign of the special status of the BMW ActiveHybrid concept is the presentation of this technology in combination with a brand new type of vehicle: BMW Concept X6 ActiveHybrid is the unusually attractive vision of a truly innovative  vehicle virtually predestined for such cutting-edge drivetrain technology.



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