The Volkswagen Jetta TDI is currently the least expensive diesel-powered car in the United States. Diesel take rates---according to Dr. Johannes-Joerg Rueger, the senior VP of diesel engineering at Robert Bosch GmbH---are currently racking up at an impressive 30 percent of overall Jetta sales in the U.S. (58,721 units from January 1 through July 31, 2009), including a whopping 80 percent of Jetta wagons. We recently met with Rueger and his colleagues at Bosch (which happens to supply numerous diesel-specific parts including injectors and particulate filters), and they believe that Jetta sales are a sign that sales of diesel cars are poised to significantly increase market share in the United States.

Forget all the hype about an imminent battery-powered future, Rueger said. Bosch believes that diesels will appeal to people in the medium term and sees diesel's North American market share increasing from its current 3 percent to approximately 15 percent by 2015 in vehicles weighing less than 14,000 pounds (the size of a Ford F-450).

And how many cars will be hybrids or electrics in '15? Bosch is predicting that the worldwide share will be only about 5 percent.

"Over the next twenty years, the dominance of diesel and gasoline engines in the car will remain unchallenged," Bosch's President of gasoline systems, Wolf-Henning Scheider, recently stated. "We expect the mass market for hybrid and electric drives to develop slowly at first, "In 2015, five million of the 85 to 90 million new cars produced will have hybrid drives. Another 500,000 will be plug-in hybrids or electric cars. We believe that the market for electric cars will not start gaining importance until 2020 at the earliest, with six million hybrid vehicles and three million plug-in hybrids and electric vehicles out of 100 million newly produced cars."

That 2015 timeframe, of course, coincides with ever-increasing federal-emissions requirements, and Bosch is diligently working to keep diesels clean enough to pass the tests. This includes exploration in three methods of reducing harmful nitrous-oxide emissions:
--lean NOx traps (a.k.a. LNT, as found in the Jetta TDI)
--urea injections (as found in the Mercedes-Benz E320 Bluetec)
--clean it in the engine, not the exhaust (as being developed by Navistar, whose diesel-building deal with Ford will soon expire)

Regarding compliance with the upcoming regulations, Rueger says, “There’s no way to do that with the old stuff,” which is why Bosch is so busy these days. Some might point to Europe, where diesels make up about half of the marketplace and mpg figures seem to embarrass those printed on Monroney stickers here in the States, but Rueger notes that cars in Europe are typically about 1100 pounds lighter and have 0.5- to 1.0-liters less engine displacement.

Gasoline-slurping enthusiasts should rejoice in Bosch’s prediction that internal-combustion engines will power the plurality, if not the majority, of vehicles on the road “for quite some time.” But green fans, don’t hang your heads: direct injection and other technologies are making it possible for traditional gasoline and diesel engines to play a major role in cleaning up the national fleet.

Clearly the days of completely careless consumption are quickly becoming a thing of the past. But EVs and hybrids aren’t the only ways to skin a cat. As Bosch suggests, diesel has a growing---although not huge---role in raising the efficiency of the American fleet.

By Rusty Blackwell, with contributions from David Zenlea and Eric Tingwall