Drive Time

Clean Diesels Are Coming

Meet the Smart car, part of a new generation of fuel-efficient, diesel-powered cars that are also fun to drive.

By Mark Solheim, Senior Editor, Kiplinger's Personal Finance

April 22, 2005

It is Earth Day, so please cut me a little slack for starting this column with a discussion of an amazingly fuel-efficient car that isn't available yet in the U.S.

The Smart car is a family of tiny vehicles built by DaimlerChrysler for European and Canadian markets. It was supposed to arrive here this fall. But the Smart division's gushing red ink and problems meeting our emissions standards put a hold on the U.S. debut.

Undaunted, the folks at Diesel Technology Forum, an industry-funded group dedicated to promoting the new generation of clean diesel vehicles, imported the Smart Fortwo Cabriolet from Canada to show journalists that vehicles don't have to be environmental nightmares.

Tiny, but not tinny

The wedgy little two-seater (just slightly more than eight feet long) comes with either a gasoline or a diesel engine. With its 0.7-liter gas engine, the car gets a thrifty 38 mpg in the city and 57 on the highway. But the turbo-diesel version gets 62 mpg on the highway and 51 in the city, rivaling the somewhat inflated numbers Environmental Protectional Agency lists for the Toyota Prius gas-electric hybrid.

The secret: It weighs a scant 1,600 pounds, which allows it to be powered by a three-cylinder engine. It's kind of like a Harley with a retractable roof. The zero to 100 kilometer-per-hour time (that's 62 mph) is an uninspiring 20 seconds, so it's not ever going to fly with the tuner set.

But speed isn't the point. I went to dinner in a trendy neighborhood where parking is usually impossible, and the car easily fit in a space not even the Mini Cooper could have squeezed into. Filling the tank costs about $13 and takes you 360 miles on the highway. And driving the thing around Washington, D.C., where people are generally ho-hum about presidential motorcades, ultra-expensive cars and other street sights, garnered a lot of looks and a few thumbs-ups.

Despite its tin-can appearance, this Smart is a safe car. Independent crash tests in Europe have demonstrated it to be one of the safest cars in its (albeit) supersmall segment. Anti-lock brakes, side airbags and electronic stability control (to help avoid skids) are standard.

Gasoline versus clean diesel

Diesel fuel averages a couple of cents more than gasoline per gallon, but diesel engines typically burn at least 30% less fuel than gasoline engines of similar power. For example, the Volkswagen Golf GL TDI (about $18,000) gets 38 mpg in the city and 46 on the highway, versus 24 city and 31 highway for the gasoline version.

Diesels also produce lower emissions of greenhouse gases, such as carbon dioxide and carbon monoxide. Government standards slated to phase in by 2007 will require even cleaner-burning engines. (Until those standards are met, diesels can't be sold in California and in a cluster of northeastern states -- Maine, Massachusetts, New York and Vermont.)

The technology has come a long way since the smoky, smelly, clattering vehicles of a generation ago. In the early 1990s, there was a switch from indirect to direct injection of fuel into the cylinders at high pressure. That created more efficient engines with more torque -- the power to tow and accelerate from low speeds -- han gasoline engines of the same size. Then, a few years later, advancements in turbo-charging made diesels more fun to drive.

Although about half of cars sold in Europe are diesels, selection of diesels is sparse here in the U.S. VW offers a diesel version of nearly every model it sells. Mercedes-Benz sells a diesel E320, and the Jeep Liberty comes in a diesel version. The price premium is usually $500 to $1,000.