Chris Hynes' new diesel car has passed a crucial road test.
"The car is paying for itself," he says. "I believe the money I am saving in the fuel is going toward the payments for the car."
Hynes now spends $200 less per month on fuel -- and gets 30 more miles per gallon than he did with the gas pickup he traded in last year.
That kind of fuel economy -- 30 percent better than comparable gas vehicles -- is renewing interest in diesel cars. At Pugi Volkswagen near Chicago, demand has tripled.
"Anybody and everybody is looking at diesels now," says Chris Willuweit, of the VW dealership.
That's why automakers, from Detroit to Tokyo, are now putting diesel production in the fast lane -- from SUVs and pickups, to luxury and mid-size cars.
"Currently about 3½ percent of all new vehicles sold are diesels," says Anthony Pratt of JD Power and Associates. "By 2015, we expect that to grow to 12 percent."
Americans have been down this road before. At the height of the 1970s oil crisis, automakers rushed a slew of smelly and noisy diesels onto the market.
Since then, engineers like Don Hillebrand have spent thousands of hours trying to clean up diesel's dirty reputation.
"Literally, they're 98 percent cleaner," says Hillebrand, transportation research director for the non-profit Argonne National Laboratory. "I mean, what used to be a bucket of emissions is now a drop."
But that's still not clean enough in five states, including California and New York, where even the new diesels don't meet emissions standards -- though automakers are aiming for compliance by the end of the decade.
Some say it's a waste of time and money.
"Do we invest in a new generation technology, which is hybrid technology," asks Brendan Bell of the Sierra Club, "or do we move backwards and go to diesel vehicles?"
When it comes to engine noise, proponents of today's diesel cars claim they're almost as quiet as today's gas vehicles.
When ABC News checked under the hood of a gas-powered Volkswagen Jetta, a sound meter showed a decibel reading in the low 70s, about as loud as a small vaccum cleaner.
The diesel Jetta got a reading in the low 80s -- noticeably louder. But behind the wheel, according to Hynes, "it's a very quiet car."
And with the money he's saving, Hynes and other diesel drivers may not mind a little extra noise.