Thanks to new technology developed during the past decade, new cleaner-burning diesel-engine vehicles will be available in all 50 states. Mercedes-Benz has started it off with leases for the E320 Bluetec (in small numbers) right now in California, followed by the four other states that follow California emissions regulations (New York, Massachusetts, Vermont and Maine). They will be followed next year by Volkswagen (the Jetta and Sportwagen in the Spring of 2008), Audi (the Q7 by the end of 2008), BMW (undetermined vehicles, but likely to be the 5 Series or 3 Series) and more Mercedes-Benz models (the M-Class, R-Class and GL-Class).
Following in 2009 and 2010 will be a further onslaught of diesel cars and trucks from Honda, Hyundai, Chrysler, Nissan, Ford, and General Motors. With diesels already outselling hybrids (thanks to the heavier pickup trucks from GM, Ford and Dodge), the prospect looks good for diesels to hit a market share of about 25 percent by 2015. These diesel engines are not like any you may remember, unless you've been to Europe recently. They employ modern technology like common-rail fuel delivery systems that maximize combustion efficiency (for great fuel economy and low emissions) and particulate filters and NOx traps that minimize tailpipe emissions. And they are even cleaner than the European models, since California emissions standards are the most stringent in the world. One key that enabled these clean diesels was the introduction of ultra low-sulfur diesel fuel last year. Taking the sulfur out of the fuel allowed automakers to fashion more efficient aftertreatment of the pollutants coming out of the engine.
What is not different are the attributes that have made diesel-engine cars the most popular models in Europe (where they have captured more than 50 percent of new car sales). They offer 20- to 40-percent better fuel economy than similar gasoline models while also delivering better power off the line than those cars and of course meeting the same emissions standards. The improved fuel economy translates into lower CO2 emissions, which has enhanced the appeal of diesels in Europe and may do the same in the U.S.
For those benefits, diesels do cost more than similar conventional vehicles, though in models offered so far the differential is not as great as with gasoline-electric hybrids. Of course, the other advantage of a diesel engine is its historic longevity.