STEVE INSKEEP, HOST:
There's another comeback happening in Detroit. Some carmakers are making significant investments in a fuel that is not new at all - diesel. The newest diesel engines are far cleaner than their predecessors, and they get many more miles per gallon. The question is, what's holding customers back from switching gas pumps?
NPR's Sonari Glinton reports from the floor of the North American International Auto Show, in Detroit.
SONARI GLINTON, BYLINE: When you look around the auto show, there's a lot of energy. There's a lot of money being spent again, and there's one topic that keeps coming up - fuel economy. Scott Yackley is with General Motors.
SCOTT YACKLEY: Yeah. As you can see around the auto show, it's a major driver. Everywhere you go, there's fuel-economy numbers. Even on the sports - ultra-luxury sports cars, they're talking about fuel economy. So fuel economy overall is very important.
GLINTON: Now, Yackley should know. For the past seven years or so, he's been living and breathing fuel economy. He's one of the engineers who engineered an engine for GM's all-new midsize trucks. It's diesel. And if the auto show is report card day for engineers and designers, you can hear Yackley puff up with pride when he describes his recent work.
YACKLEY: It's got a capability beyond the other two gasoline engines - with respect to towing, torque, payload - and it's really fun to drive. So you get all those additional benefits; it's fun to drive; and above all, this diesel is expected to be the most fuel-efficient truck in the industry.
GLINTON: GM is not the only carmaker launching diesel trucks. Chrysler announced it's putting diesel into its Ram truck. And while the American car companies are rolling out diesel engines slowly, Volkswagen is expanding its portfolio in the U.S. with second- and third-generation diesel.
OLIVER SCHMIDT: Diesel is our technology for fuel efficiency.
GLINTON: Oliver Schmidt is head of engineering and environment with the Volkswagen Group of America. He says diesel is still getting a bad rep from a terrible try 30 years ago. He says people still ask if they're loud or smelly.
SCHMIDT: And they ask if they are smoky because they've been on this school bus when they were kids. But with current emission regulations, this is gone. All the stinky, smelly stuff - that is gone. The diesel is as clean as the gasoline car today. And with future emission regulations that are coming up, they are getting even cleaner.
GLINTON: Schmidt says Volkswagen is selling a lot of diesels. And they're selling them in the middle of the country, where drivers are doing a lot of highway miles. Diesel engines get much better mileage on the highway.
But what accounts for the slow adoption - or re-adoption? Margaret Wooldridge is a professor of engineering at the University of Michigan.
MARGARET WOOLRIDGE: I mean diesel - small diesel engines for passenger vehicles are agile; they meet emissions regulations. But the fear is that people just won't buy them.
GLINTON: There is some worry about refueling a diesel. Diesel is not nearly as ubiquitous as gas; there are about a quarter as many stations. However, they tend to be grouped on highways and interstates. And in real-world driving, diesel owners report getting as much as 50 miles per gallon. But a diesel doesn't come with a - you know, a little green leaf or emblem saying hybrid, so drivers don't get the street cred they might get with say, a Prius. Again, Margaret Wooldridge.
WOOLRIDGE: I think primarily, that's cultural, and that's the U.S. bias against diesels. So all those automakers sell diesel engines - diesel passenger cars in Europe, for example - at very high production amounts, production volumes.
GLINTON: Wooldridge says in order to get to the new fuel-efficiency standards, American car companies will have to get over that bias because they can't leave out any technology - even an old one, like diesel.
Sonari Glinton, NPR News, Detroit.
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