Diesel engines have never been more in demand - or more scrutinized by regulators. Diesels always have enjoyed good fuel economy. Now, new technology has made them cleaner and more responsive on the road. That is making them increasingly popular even in the United States, where diesel demand has long been low.
Yet, regulators in North America, Europe and Asia are demanding new efforts to improve diesels for the environment. 'It's a major challenge,' says Dick Baker, a technical specialist on Ford Motor Co.'s research staff. 'We're running hard to keep up with new technology, but we're also having to keep up on emissions.'
General Motors' diesel development chief Fritz Indra adds: 'Engineers are never alone with their ideas. No matter the best techniques, the government is always with them.'
In Europe, where fuel prices top $19 per liter, one quarter of all cars and trucks are equipped with diesels. In countries where governments have encouraged diesel use, such as France and Italy, up to 50 percent of all new vehicles are diesel-powered. Each of Europe's major automakers has introduced, or has under development, new families of diesel engines designed to match the performance of gasoline engines.
Just this summer, DaimlerChrysler purchased Detroit Diesel, the engine manufacturer owned by race-car champion Roger Penske. DaimlerChrysler already owned a 20 percent stake in Detroit Diesel, which produces diesel engines for Chrysler Jeeps and minivans sold in Europe. Now, Detroit Diesel will join forces with Daimler's MTU engine business to create a $7 billion engine giant called the Commercial Vehicles Unit. DaimlerChrysler claims it will be the world's biggest producer of medium and heavy-duty diesels.
It is easy to see why Detroit Diesel would be attractive: Almost everywhere, diesels are the engines of choice for heavy-duty trucks and buses. The reason is simple: a gallon of diesel fuel yields 30 percent greater fuel economy than an equivalent gallon of gasoline. Diesel engines also are renowned for durability. It is common for a diesel engine to outlast the truck in which it is installed, says Cummins Engine Vice President Christine Vujovich.
But diesels historically have been far dirtier than gasoline engines. That reputation - still a reality for many diesels - has launched a continuing battle between regulators and automakers. In some cities, such as Beijing, regulators are threatening to ban diesels.
In the United States, regulators are cracking down on diesels. The Environmental Protection Agency wants oil producers to cut sulfur, a key impurity in diesel fuel, by up to 97 percent. It also wants automakers to vastly reduce the amount of pollution emitted by pickup trucks, the most common diesel-powered vehicle in the United States.
Oil companies say cleaner diesel fuel will cost up to 10 cents more per gallon, well exceeding the EPA's estimate of 4 cents. Engine makers say they cannot even measure pollutants at the low levels decreed by the EPA. And environmentalists claim the auto industry has been given too much time to clean up.
In Europe, regulators want to cut carbon dioxide emissions from both gasoline and diesel engines. Engines now are allowed to emit carbon dioxide pollution of 180 grams per kilogram of fuel burned. The European Union wants to cut that to 140 grams by 2008 and to 120 grams by 2010.
In Asia, governments are stepping up scrutiny of diesel engines. In Japan, where soot emitted by diesel engines is estimated to be 2.5 times as much as allowed in the United States and Europe, lawmakers for the first time have recommended that diesel engines be equipped with pollution filters. Companies are resisting because the move could cost up to $40,000 per vehicle.
China, where pollution in big cities can be so thick it leaves dust on clothes, is taking more drastic steps. Starting January 1, Beijing's city government banned all new diesel vehicles, while 12 other cities also took regulatory action. The move comes as China's diesel production is soaring. Last year, Chinese factories produced 475,000 diesels for trucks and buses, up from just 50,000 a decade ago.
Diesel engine makers such as Cummins are scrambling to keep pace. 'When you have different standards in the U.S., China, India and Europe, you almost end up making four different engines,' Vujovich says.
But the regulatory moves coincide with the development of cleaner engines and fuel that bears little resemblance to their predecessors. In many cases, says GM's Indra, it is difficult to tell whether you are at the wheel of a gasoline-powered or a diesel automobile. 'The big progress is drivability,' he says. The latest diesels are 30 percent more fuel efficient and emit one-tenth the pollution of engines 10 years ago, he says.
To make diesels even cleaner, experts agree that truck makers must develop catalytic converters like those on cars and light trucks. The idea of installing catalytic converters on diesels astounds those who never expected diesels to have to meet the standards gasoline engines do. But Ford's Baker predicts: 'The diesel will end up similar to gasoline engines. We'll see a lot more exhaust treatments.' That is a daunting prospect for a company that has diesels as small as 1.4 liters for European compacts and as big as 7.4 liters on the Ford F-series pickup.
But the world's automakers already are taking action. In August, Toyota announced that it has developed a platinum catalyst for diesels that will clean nitrous oxide and soot, diesel engines' two main pollutants. The device will be available in 2003.
Meanwhile, Peugeot will introduce a filter that traps diesel soot. Such filters, which trap soot before it goes out the tailpipe, have been in automakers' research laboratories for years. But at a cost of $100-plus per vehicle, they have always been dismissed as too expensive.
'When you're talking about gasoline engines, you are talking about millions and millions built and sold. You can make manufacturing efficiencies to bring down the cost,' explains Harish Chawla, Ford's chief program engineer for diesel motors. 'With diesels, we don't have that high a volume' - at least, not in the United States.
But tightened regulations and increased demand are prompting companies to look at ideas they once discarded. 'Five years ago, everybody would have said you were crazy' to install such a costly filter, says GM's Indra. 'In 2007, everyone will be doing it.'
That prediction is encouraging to diesel makers, who see a bright future for diesel-powered vehicles even as regulators bear down. 'Just to maintain our position, we have to keep running on diesel technology,' says Ford's Baker.
Adds Cummins' Vujovich: 'It's a big intellectual challenge, not to mention a financial challenge. But if we were to stop producing diesels, the world would screech to a halt.'
You can e-mail free-lance writer Micheline Maynard at [email protected]