2010 BMW ActiveHybrid 7
2010 BMW ActiveHybrid 7. Click image to enlarge

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2010 BMW ActiveHybrid 7

Munich, Germany – BMW is not a company you’d normally associate with hybrid cars – perhaps because few people associate “hybrid” with “performance” – for so long one of BMW’s hallmarks.

Well, that’s about to change, because the German automaker will launch not one, but two hybrid models in the next six months, starting with the X6 ActiveHybrid this December, and following it up in the spring of 2010 with the ActiveHybrid 7 that you see here.

When you consider the company’s engineering and technological prowess, combined with its increasing pursuit of “Efficient Dynamics”, the move makes sense. Long-term, BMW sees these vehicles as a step on the path to full electrification. (Company officials are quick to note however that BMW isn’t concentrating on any one long-term mobility solution; it has also been heavily involved in hydrogen-powered internal combustion engines.)

2010 BMW ActiveHybrid 7
2010 BMW ActiveHybrid 7. Click image to enlarge

It probably doesn’t hurt that Mercedes-Benz and Lexus are both offering hybrid models in the same premium large sedan segment as the 7 Series, with the S400 Hybrid and the LS 600h L respectively.

Interestingly, although the two BMW ActiveHybrid vehicles would seem to be simply the same hybrid driveline fitted into two different body styles, this is not the case. The X6 ActiveHybrid is a “full” hybrid that can be driven on electric power alone, while the ActiveHybrid 7 is a “mild” hybrid which can’t.

Actually, the only real commonality in their hybrid powertrains is the “N63” 4.4-litre, direct-injected and twin-turbocharged gasoline V8, a motor also found in several non-hybrid BMW models. This engine is unusual in that the exhaust and twin turbochargers are mounted in the valley of the “V”, the opposite of most conventional V-engines.

In the ActiveHybrid 7, this V8 is tuned to produce 40 more horses than the normal 750i/Li’s 400 hp. The slight delay in turbo-boost production that might result from the higher state of tune is offset by the assistance of the hybrid system’s electric motor.

2010 BMW ActiveHybrid 7
2010 BMW ActiveHybrid 7
2010 BMW ActiveHybrid 7
2010 BMW ActiveHybrid 7. Click image to enlarge

Said motor is a compact, 15 kilowatt (approximately 20 hp), 3 phase synchronous AC unit that is bolted to the crankshaft in place of the flywheel. Immediately behind it is an 8-speed ZF automatic transmission (the “8HP”) that is – with certain necessary changes, mostly relating to supplying oil pressure at low/no engine rpm – essentially the same that is used in some non-hybrid Bimmers.

This means that unlike many hybrid vehicles, which often use continuously variable transmissions, its behaviour is completely conventional, and it has clearly defined ratios. Upshifts are smooth, even under full throttle, and it’s quick to provide an appropriate downshift, even if that means skipping a few gears to do so. No oddly disconnected CVT feel here.

Drivers unfamiliar with newer BMW products may find a learning curve involved in the ActiveHybrid 7’s shifter, however. It returns to centre after selecting reverse or drive just like the even weirder joystick gear selector in a Toyota Prius, however it also requires that you simultaneously depress a side-mounted “Unlock” button while making your selection. Otherwise, your request will prompt a procedural reminder from the central control screen, but be summarily ignored by the transmission. (A second, top-mounted button engages Park; a separate switch on the console operates the electrically actuated parking brake.)

The electric motor’s direct connection to the crankshaft allows it to function as the starter, and with nearly ten times the output of a typical gear-drive starter and a peak of 155 lb-ft of torque, engine rotation is both certain and nearly instantaneous. Its design facilitates an idle-stop function that contributes additional fuel savings; brake to a complete stop and the gasoline motor shuts off, release the brake pedal and it restarts.

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