Diesel's been around forever. OK, not forever but for almost as long as gasoline engines have existed. But there's renewed interest as automakers look for better mileage.
Diesel engines are extraordinarily fuel-efficient, often getting highway fuel economy numbers similar to that of gasoline-powered hybrid cars.
While diesel cars are commonplace in Europe, where the price of diesel fuel is deliberately kept low compared to gasoline, they still haven't made huge inroads in the U.S. Volkswagen has had success with them, though, with 22% of the cars the brand sells here running on diesel.
The high price of diesel fuel is one reason more automakers aren't jumping on board. Paying more per gallon seriously eats into a driver's cost savings.
Then there are strict emissions rules that pile on more cost. In order for diesel cars to burn cleanly enough to meet the rules, expensive exhaust cleaning technologies have to be added. By the time it's all done, a diesel VW Jetta, for instance, ends up costing about $2,200 more than its gasoline-powered sibling.
One thing that's not a factor is the performance of the engines. Modern turbo-diesel engines sound nice and, except perhaps when first started on a very cold day, perform very well.
Tesla Motors unveiled a new SUV that the automaker plans to put into production by 2014.
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