Driven by economic and environmental concerns, diesel-engine cars are gaining traction in Europe. Will the mania for compression ignition make a comeback in America?
Paul A. Eisenstein
From the Print Edition:
Tom Selleck, Nov/Dec 2007
Two new BMWs sit idling under the broiling Spanish sun. My first thought is simply to get inside, out of the heat. But I'm here for a test drive, not a siesta, so I jump into the nearest sedan, shift into gear and tear out of the parking lot that serves as our preview headquarters. Racing onto the Autovia, I nail the throttle and watch as the speedometer soars to 225 kmh, then ease back before turning off the freeway onto some winding local roads.
"I'm impressed," I tell the German engineer, who has tagged along as my copilot. "Yes," he says smugly. Then, with a curious grin, he adds, "But I was surprised you picked this car, since this version isn't coming to the U.S."
After nearly 30 years covering the auto industry, I pride myself on my instincts. Maybe I'm just an idiot savant, but I normally can spot and identify individual models from a half-mile away, at night, simply by their taillights. But this time, I've been surprisingly oblivious. Rather than grabbing a 330i, I've spent the last hour riding around in a 335d. That's "d," as in diesel, a name that doesn't generally sit well with American motorists. And for good reason.
Following the twin energy shocks of the 1970s, U.S. motorists were desperate to slash their fast-rising fuel bills. While some manufacturers turned to downsizing—replacing their big sedans and V-8s with pint-sized econoboxes—other makers, especially those from Europe, tried another approach. With diesels, marques like Mercedes-Benz could continue offering the large, lavishly equipped products their customers expected, while delivering significantly better fuel economy. By the mid-1980s, diesels powered more than two out of every three cars the German company sold in the States. Not surprisingly, other brands jumped onto the diesel bandwagon, including General Motors' then-formidable Oldsmobile.
Things didn't work out as planned. To shave costs and slash development time, Olds engineers tried to convert a gasoline engine to run on diesel, a disastrous decision due to the enormous compression generated inside an "oil burner." Even the best diesels of the day were slow, rough-riding and foul-smelling, but when thousands of Olds engines began failing catastrophically, the damage was done, and the U.S. diesel market went into a fast decline. Today, these high-mileage engines account for little more than an asterisk on the American automotive sales charts.
Not so in Europe, which is in the midst of a full-blown diesel revolution. From econocars to the most luxurious vehicles, a new generation of oil burners now accounts for more than half the market. In some countries, such as Austria and France, that share is closer to 70 percent—and growing. Of course, the new 335d isn't your father's Oldsmobile, which is why it's not surprising—I hope—that even an automotive expert might be fooled by the latest diesel technology. And why a fleet of new diesel vehicles will soon be arriving in U.S. showrooms.
Clean Fuel, Clean Air
In his most recent State of the Union address, President George W. Bush called on the country to "make our air significantly cleaner" and to become "much less dependent on foreign sources of energy." Achievement of those dual goals, he asserted, would require "technology and innovation."
Perhaps nowhere in the automotive world have engineers achieved so successful a technological transformation than with the diesel engine. Sure, there's plenty of talk about gasoline-electric hybrids. And if the futurists are to be believed, we'll someday drive to the grocery store in hydrogen-powered fuel cell vehicles or even battery cars. But in the nearer term, diesels are yielding dramatic improvements in fuel economy—often up to 40 percent more mileage than comparable gasoline engines—while avoiding their past drawbacks. As I discovered behind the wheel of BMW's 335d, they can be quick, smooth and amazingly clean.
It helps to start with cleaner diesel fuel. That means ridding it of sulfur—the stuff the ancients called brimstone and likened to the noxious odors of hell. Much like the lead that once was found in our gasoline, sulfur poisons the latest pollution control hardware. Until a few years ago, it wasn't unusual to find sulfur concentrations as high as 2,000 parts per million at U.S. pumps. By comparison, European refiners were required to ship diesel with 50 ppm of the devil's element. Federal regulators finally acted, last year, requiring that the vast bulk of the fuel sold in the U.S. meet new "ultra-low" standards. That translates into a maximum 15 ppm, a figure even tomorrow's more advanced emissions systems can live with. "This is the enabler of future diesel technology," declares Jens Mueller-Belau, technical manager for the Dutch energy giant Shell.
To compare Mercedes' new Bluetec power train with the diesels the maker used a quarter-century ago would be akin to pitting an open hearth against a Viking grill. Of course, it also helps to understand how fire is started in the first place.
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