Funny how BMW uses IBS to take the load off the electrical charging system during certain driving conditions, whereas many other manufacturers are using these inertia pulleys on their alternators. It's simply a one-way clutch or sprague that drives the alternator under acceleration and free-wheels during deceleration. It takes a lot of stress of the drive belt and attached accessories too I'd imagine. But, being a mechanic myself, they are suscepible to failure, as I've already seen on a few vehicles. I'm interested to see if BMW follows suit on this new design adoption. Maybe they already have, since I'm not too familiar with anything in or beyond the G series.

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2008 X5 4.8i w Sport pkg
2007 X3 3.0si
2002 330xi