BMW’s latest generation of engines has now been on our roads for almost two years. These engines balance fewer cylinders with greater use of turbocharging. Where there were mostly six-cylinder engines in the U.S. models, there are now many more four-cylinder variants; where V-8s had dominated the flagship 6- and 7-series, are now also turbocharged sixes.
BMW’s expressed goal is to meet the performance expectations of BMW drivers while also complying with tightening EU and U.S. regulations. In the U.S., these regulations appear as “CAFE” (corporate average fuel economy) standards; in Europe, they are framed as greenhouse gas (CO) emissions. In practice, both sets of regulations track with fuel economy, so the same technologies are used to address both sets of concerns.
Turbocharging, for example, is a happy mate to direct fuel injection (into the combustion chambers, rather than the inlet manifold): the directly-injected fuel helps to cool the warm incoming air from the turbocharger. This, in turn, allows for higher compression ratios and better fuel efficiency, as well as more power. We see quite a bit of this technology in the new BMWs. The current Minis (model year 2007 and later) already incorporate this combination.
What about hybrids? German car makers have been ambivalent about the overall benefits of hybrids, for a number of reasons. They are complex, incorporating essentially two powertrains instead of one. This adds to cost, both short- and long-term.  The additional components of this dual system compromise ride and handling when compared with the best single-powertrain cars. They have additional end-of-life recycling costs for the batteries. And those batteries are heavy, typically adding around 500 pounds to the car’s curb weight. The engineers at VW/Audi, which has an advanced line of hybrids slowly appearing in the U.S., points out that its diesel-powered cars actually have a lower overall carbon footprint — that means better fuel economy than the best of the hybrids. What is the appeal of hybrids, in that case? At least for the moment, they are the new-new thing, and have the attention of the U.S. market. However, the federal tax breaks for hybrids went away at the end of last year, and the California carpool lane privilege went away recently, except for plug-ins. Now hybrids will have to survive on their real merits, and the outlook appears different 
What about those European diesels, though? Well, they’re terrific. Most of the new cars sold in Europe for the past decade have been diesels, and their technology has advanced dramatically. They now have more power — comparable to gasoline engines — and terrific driveability. They are quiet, and they no longer smoke or stink. They have a special trap filter to eliminate carbon particles (soot), in addition to other emission controls comparable to those on gasoline engines. These “particulate traps” do add a bit to the cost. In addition, they require low-sulphur diesel fuel, but that has been available in the U.S. for three years now. Perhaps the main remaining obstacle is the memory of the diesels of 25 years ago. And then there was the sudden demise of many of those when the California change to clean-burning diesel resulted in so many expensive diesel pump failures. Whatever the reason, we look forward to more of these new diesels in the U.S. The European BMW and Mini Cooper diesels drive wonderfully.
Electric cars haven’t been ignored. BMW says it has invested over three billion dollars in research and new facilities for its i3 and i8 all-electric models. These cars have a strong but lightweight carbon fiber body, some of which comes from a new plant in eastern Washington state. Final assembly in Germany is in state-of-the art factories. However, this “high concept” automobile may take awhile to establish itself on the roads, as the current demand—and past track record—for all-electric cars is extremely spotty. Tesla is the exception at the moment, though their total numbers are still very small. The Nissan Leaf  is the current best-selling electric car worldwide, but still accounts for only 3,000 cars per month in the U.S. The limited range of electric cars is still a very big issue in the real world. few are planned for sale in the U.S., and those in metropolitan areas only. Range is a very big issue in the real world of driving.
Those of us who can avoid traffic jams and actually enjoy driving have reason to be optimistic about the future. There are wonderful new technologies just around the corner, with names like “HCCI” (gasoline-fueled diesel designs), “Scuderi Split-Cycle,” (100/1 compression) and many others, giving new life to internal combustion. Natural gas is a good fuel which is currently abundant, low-polluting, inexpensive, and needs only a buildout of its supply infrastructure. In other words, the same refueling issue that haunts electrics and the upcoming fuel cell cars.
If you’re wondering whether this is a good time to trade your existing car for one of the latest ones, our opinion is — who knows? The really good models are only known through experience, and there are no technology breakthroughs sitting in the showrooms at the moment. We would stay tuned — the really good choices are yet to appear. And in the meantime, we recommend hanging back from the first year’s production of any new model. All car companies have a learning curve.