Diesel revs up as potential alternate fuel

Americans are clamoring for cars with diesel engines.

But the automakers, who are quite used to selling diesels in Europe, seem content to offer these generally more fuel-efficient engines mostly in trucks for the US market.

Many consumers have seen the small diesel-powered cars in Europe, though, and wonder why they can't get those same vehicles here. It's one of the most common questions sent in by readers, often just after they return from a European trip.

In Europe, nearly half of all passenger vehicles are sold with diesel engines. Diesel fuel there is cheaper than gasoline, and the cars that run on diesel have higher fuel-economy ratings than their gasoline-powered counterparts.

General Motors Corp. sells 17 diesel-engine variants in 45 vehicle lines around the world, the company said recently, but has none in cars for sale in the United States.

GM said it sells more than a million diesel-powered cars and pickup trucks annually, ranging from a 1.3-liter four-cylinder in the Opel Agila and Corsa, up to the 6.6-liter Duramax V-8 that is available in the Chevrolet Silverado and GMC Sierra heavy-duty pickups in the US market.

The 1.3-liter engine, whose fuel economy rating is around 40 miles per gallon, is not sold in the United States, though, and there are no plans to bring it here.

It does not meet the more stringent US smog regulations, let alone the even more restrictive rules in effect in California and several northeast states that have adopted the California standards.

For diesel-starved Americans, though, some help is on the way.

While this year's diesel offerings are primarily limited to larger-than-full-size pickups, there also is a high-dollar diesel version of the Jeep Grand Cherokee, a premium-priced Mercedes sedan, a Mercedes sport utility vehicle and a V-10 diesel-powered version of the Volkswagen Touareg SUV.

Coming soon will be light-duty full-size pickups from all of the Big Three US automakers, and perhaps even some more SUVs and some midsize or larger cars.

And that's not to mention at least one small-car diesel from Volkswagen - a new version of the compact Jetta sedan.

VW, the German automaker, also is considering adding a diesel option to its Rabbit (formerly Golf), and maybe even bringing back the diesel version of the New Beetle that was sold earlier this decade.

The Jetta was the most recent diesel car offering from Volkswagen, with very limited availability through the early months of 2007 as a carryover 2006 model.

In the 2006 Jetta, the diesel engine with an automatic transmission is EPA rated at 35 miles per gallon in the city and 42 on the highway, compared with 25 city/ 32 highway for the most fuel-efficient gasoline engine.

No 2007 Jetta diesel was produced because the Jetta's engine did not meet new EPA smog regulations that took effect for the 2007 model year.

Volkswagen said last week that even if a Rabbit diesel is offered next year, it will not be a 50-state model. But VW is among those working on diesels that will be offered in all states.

Even with the US switch to new low-sulphur diesel fuel this past fall, diesel engines that already had been on sale here generally did not meet the new EPA standards. They will, soon, though, the automakers promise.

GM said recently it will introduce a new, state-of-the-art 4.5-liter Duramax V-8 turbodiesel engine for use in light pickups and the Hummer H2 sport utility built beginning with the 2010 model year.

That engine is expected to improve fuel efficiency 25 percent, to reduce carbon dioxide emissions 13 percent and to cut particulates and nitrous oxide emissions, which are problematic with diesels, by at least 90 percent.

The compact new diesel, which will be about the same size as GM's current small-block V-8 gas engine, will be able to fit under the hoods of the light trucks, where the larger Duramax diesel used in the heavy duty pickups will not.

GM said it plans to invest $100 million in its Tonawanda, N.Y., engine plant to produce the 4.5-liter diesel, which will be offered in the H2 as well as the Chevrolet Silverado and GMC Sierra light-duty (1500) model pickups.

To help facilitate the adding of diesels to other vehicles - perhaps even some for the US market - General Motors last week said it had purchased 50 percent of Italian diesel-engine maker VM Motori SpA from Penske Corp., which will keep half-ownership.

GM vice chairman Bob Lutz has said GM plans to sell some diesel cars here, but he gave no timetable.

A 2.9-liter diesel engine will be developed by VM Motori for use in the Cadillac CTS in 2009, GM has said. But that's planned for sale only in Europe, at least at the beginning. That engine eventually could show up in GM's US car lines if it can meet the new clean-diesel rules.

There is a good argument for relaxing standards in the United States enough to allow some of the smaller diesel engines, whose great fuel efficiency could outweigh their less-than-acceptable emissions.

Diesel fuel is 15 to 25 cents a gallon cheaper than unleaded regular gas, so there is significant savings even without considering the extra mileage the diesels offer.

In the new 2007 Grand Cherokee diesel, for instance, EPA ratings are 20 miles per gallon in the city and 25 miles per gallon on the highway versus 17/22 for the base model's V-6 and 15/20 for the 4.7- and 5.7-liter V-8 versions.