Detroit: BMW Concept 7 series: An ActiveHybrid from Bavaria

The green revolution continues its inexorable progress up through the automotive stratus with BMW's Concept 7 Series ActiveHybrid again previewed at the North American International Automotive Show. Rolled out at the LA Auto Show, the Concept 7 Series ActiveHybrid comes with what BMW touts as "the most efficient eight cylinder engine in its class" - a 4.4 liter V8 equipped with new twin turbochargers and high precision fuel injection. The 750i that debuted at Detroit uses the same powerplant.

In addition, the V8's already potent 400 horsepower and 450 ft lb of torque is nicely, environmentally, supplemented by a 20 horsepower electric motor supplying an additional 150 ft/ lb of torque if and when needed. Integrated into the transmission housing, the electric motor replaces the conventional alternator as well as the starter.

The Concept 7 Series ActiveHybrid is perhaps the most conspicuous component of BMW's EfficientDynamics concept, designed to reduce both fuel consumption and emissions in a sustainable manner across the marque's entire range of powertrains. Included are the gasoline engines equipped with VALVETRONIC and High Precision Injection featured in the new Z4, 7 series and 3 series cars as well as the Advanced Diesel with Blue Performance Technology in both the 335d sedan and the X5 xDrive35d developed specifically for the North American market.

Two hybrid systems were also showcased in at the NAIAS: the full hybrid in the Concept X6 ActiveHybrid as well as the mild hybrid in the Concept 7 series Active/Hybrid. According to BMW, the latter uses about 20-percent less fuel than comparable vehicles powered by gasoline engines alone, not to mention resulting in a 15-percent drop in emissions.

Among the other "green" highlights of the Concept 7 series ActiveHybrid is a brake energy regeneration system that powers all the on-board electrical systems. All that regenerated energy is stored in a lithium-ion battery housed in the trunk, while an auto start/stop function further contributes to fuel efficiency.

As with the rest of the new 7 series lineup, the Concept 7 series ActiveHybrid features the longest wheelbase in its class as well as bevy of BMW's proprietary electronic assistance systems including Dynamic Drive Control and Integral Active Steering, along with the new generation of BMW iDrive, Night Vision and Lane Change Warning.

Of course there are concept cars and there are concept cars. In this case, BMW expects to begin producing the 7 Series ActiveHybrid in mid-2009 and having them in showrooms by year's end.