Can 'clean diesel' power past gasoline?

To those worried about air pollution, America's enginemakers want to say two words: Clean diesel.

Admittedly, it sounds like a contradiction. Nevertheless, urged on by ever-tougher emissions standards, manufacturers and researchers are turning sooty old truck engines into clean-burning power plants.

If they meet the challenge, the nation's trucks, buses – even many of its sport-utility vehicles and cars – will be running on clean diesel for years to come.

The technology may raise the costs of driving. It will almost certainly boost the nation's freight bill. Still, it would push onto America's highways vehicles that get higher mileage and pollute less than today's cars and trucks.

"Not very many experts in this field have much faith in the future of gasoline engines," says Stephen Ciatti, a clean-diesel researcher at Argonne National Laboratory in Argonne, Ill. "Either diesel engines or fuel cells will be the likely contenders as the power plants for future transportation needs." (One environmental advocate bets on fuel cells, see story.)

Even some environmentalists acknowledge diesel has a role to play, at least in trucks and heavy equipment, if it can meet future clean-air requirements.

"Once those standards kick in, those big smoking diesel trucks we've all come to know and hate will be a thing of the past," says Frank O'Donnell, executive director of the Clean Air Trust, a Washington, D.C., environmental group.

Already, momentum is building. At last month's Paris Auto Show, 13 chief executives of the world's top automakers issued a joint statement calling for, among other things, a universal standard for and acceptance of clean-diesel technology. Diesel already powers 3 of every 10 new cars sold in Western Europe and, according to one forecast, may run half of them by 2006.

In the United States, domestic and foreign automakers are beginning to offer diesel-powered models again after a long lull. Volkswagen has built a small but fanatical following with diesel-powered Jettas, Golfs, and Beetles. Ford and General Motors now offer diesel-powered pickup trucks. And this time they promise to run cleaner and better than the models that appeared in the 1970s.

Of the five most fuel-efficient cars in the US today, the top two are hybrid-gasoline Japanese cars, followed by three diesel-powered Volkswagen models. The reason: Diesel engines remain inherently more efficient than gasoline-powered cars. And they produce less carbon dioxide, a greenhouse gas.

So when Volkswagen wanted to show off a high-mileage car of the future at its annual meeting last April, its outgoing chief executive drove a tiny diesel-powered prototype that got a whopping 285 miles to the gallon.

Of course, diesel engines have their drawbacks. They emit nitrogen oxides (NOx), which produce smog, and very fine airborne particles linked by some to thousands of premature deaths each year. By tightening emission and other standards, governments on both sides of the Atlantic have begun to push enginemakers to improve their technology.

In 2005, tough new clean-air standards will challenge European automakers to create even cleaner diesel engines. A year later, the US will require diesel fuel to meet low-sulphur requirements. Low-sulphur fuel should prove a key benefit for US automakers, allowing them to build less-polluting diesel pickups, vans, and sport-utility vehicles.

"We think there's an opportunity in the US," says Allen Schaeffer, executive director of the Diesel Technology Forum, a consortium of manufacturers based in Frederick, Md. "If you could get 40 miles per gallon in your SUV, a lot of people would be interested."

Page: 1 | 2