motor

European Bimmers with the new 8-speed automatic transmission include a fuel-saving idle-stop system like that on many gas/electric hybrid vehicles. This employs a battery-powered electric motor, sandwiched between the transmission and engine, that functions as a starter and/or generator. No word on whether this feature will be included on North American 2012 BMW 3-Series models, but it seems likely. Other possible new mpg-boosters include power steering with electric-motor assist (versus a less-efficient engine-driven pump) and a racing-style kinetic-energy-recovery system that charges the service battery or hybrid-drive battery pack while braking and coasting.
Such developments highlight a general industry trend toward vehicles with more “electrified” systems that contribute to higher fuel economy and lower emissions. Toward that end, as Autocar reports, BMW is working on a completely new electrical architecture that’s likely to be introduced as part of the F30 3-Series’ midterm update. This would be designed to accommodate electrified steering and even brakes, as well as low-energy lighting, the more-powerful batteries and motors being developed for future hybrid-drive systems, and the increasing need for more onboard computing power to coordinate all these systems and run new infotainment features. Autocar also says that BMW is developing a low-energy climate-control system that will keep the cabin constantly dehumidified by reclaiming heat from the engine exhaust. Conceivably, this could eliminate the need for a weighty air-conditioning condenser and power-sapping engine-driven A/C compressor.

More immediately, Autocar says, BMW will focus on optimizing body design to minimize fuel-wasting air drag. You won’t see anything as radical as fully covered wheels or “wingless airplane” shapes. BMW knows styling like that won’t fly with customers. What you can expect are visually subtle tweaks born of wind-tunnel work to pay fuel-economy dividends. An example is the so-called “air curtain.” This uses a series of narrow vertical intakes in the lower front bumper for channeling air to slots inside each front wheel well. The air exits the slots at high velocity to pass over the wheels, creating a virtual barrier that reduces drag in much the same way as a solid cover would. Tests show the air curtain can improve the drag coefficient of a midsize BMW 5-Series by a factor of 0.01, which doesn’t sound like much but is actually quite significant. BMW is investigating similar “airflow management” devices for the underbody and the areas around the brakes and engine bay. Because static air-smoothers like this cost relatively little, we’d expect one or more to show up in the 2012 BMW 3-Series.