Sweet Diesels Few & Far Between

I've been a fan of diesel cars ever since I wrote an article for Smithsonian magazine a few years ago about how people were making their own fuel out of waste grease or turning the grease into biodiesel at home. After doing the research, I became very optimistic about commercial biodiesel becoming available quickly, so I went out and bought a used 2002 Volkswagen Jetta diesel.

(Biodiesel can be used in existing diesel engines without modifying the engines. If you use strained grease, you need a dual fuel system so you can start and stop the engine with petroleum diesel. Otherwise, the gel in the grease creates clogs.)

I've been very happy with the Jetta: it rides like a much bigger car, even at fast highway speeds, and gets more than 40 mpg at the same time! Unlike pokey gasoline engine cars or hybrids that get similar mileage, the diesel has plenty of power--it's just plain fun to drive.

However, my hopes for commercial biodiesel have not turned into reality. There are all sorts of obstacles to getting the fuel distributed nationally, not least of them that regional fuel depots don't want to invest in necessary new facilities to handle it. Furthermore, we've been shipping most U.S. biodiesel to Europe where diesel cars dominate. And then, when the price of petroleum diesel finally dropped to more reasonable levels, it put biodiesel--made here mainly from soybeans--at a competitive disadvantage.

Even so, when we recently decided to get rid of our gas-powered family-sized car that we use for long trips, I thought I'd trade the Jetta for a new VW Passat diesel, which Volkswagen had promised to bring to the U.S. sometime this year. It's a bit larger and therefore a bit safer on highways where you dance with tractor-trailers, and yet would get excellent mileage.

But no. A spokesperson for VW says they've changed their minds, and there will be no Passat diesel anytime soon. Bummer.

Unfortunately, there are very few diesel cars yet available in the U.S. You can get an improved Jetta diesel or a diesel SUV in a luxury brand, but there are very few to choose from otherwise.

This despite the fact that diesels get 20 to 30% better mpg than comparable gas cars with all the torgue and durability you could want. And, thanks to new technology and ultra-low sulfur petro diesel, new models meet the strictest (California) air pollution standards.

Still, I was left with the reality that we needed another car, so I did the research, looking for a full-size gasoline vehicle with good mileage. So discouraging, because essentially there are none. Then I discovered the Mercedes Benz E320 diesel, introduced in 2008, with the new clean technology. It promised to get about 25 mpg in local driving, and in the 30s on the highway.

I located a used one with about 20,000 miles on it, trekking over the George Washington Bridge in New Jersey to see it. I got in for a test drive, and I hadn't gone 200 yards before a smile spread across my face: this is one sweet ride!

Quiet--no more loud diesel noise. Smoke-free--no more nasty tailpipe emissions. Smooth. Everything about this vehicle is smooth and powerful. I bought it.

It cost more than we'd expected to spend--although buying it used saved a lot--but we figure it will last a good 10 years. And I've been averaging close to 30 mpg in my combined stop-and-go and local highway driving.

Too bad the automakers are so slow about bringing more sweet diesels to U.S. car buyers.

Green My Ride

With the price of gasoline pushing $4/gallon, folks who want to stop bleeding dollars at the gas pump should check out Sierra Magazine's article on green rides. I did a lot more research for this article than could fit on the two-page spread, so here are some other good choices to consider:

• 4-wheel drive SUVs: the Mazda Tribute Hybrid gets 29 city and 27 highway, just like the Ford and Mercury Mariner Hybrids (identical to each other but for the brand name). These vehicles have enough interior space for the kids and the dog and the skis, and the sure-footedness of 4-wheel drive. Amazingly, Ford is making only about 20,000 of these a year, most of which seem to have been snapped up by NYC cabbies, so expect to wait six months if you want one.
  
• Wagons. The best mid-size is the VW Passat Wagon, which gets 20 city and 28 highway with an automatic transmission. The KIA Rondo (19/26) and Saab 9-5 Sport Combi (18/26) do slightly worse in the city but almost as well on the highway. Among the smaller wagons, the Honda Fit (28 city, 34 highway) comes out on top, but the Pontiac Vibe (23/33) and Toytoa Matrix (26/33) trail close behind.
• Large & Mid-Size Sedans. The large Honda Accord (22/31) and Hyundai Sonata (21/31) do a lot better than most. In mid-size cars, (size designations are based on interior passenger and cargo volume, not overall length or width), the hybrid Prius (48/45) is the hands-down winner, but the Nissan Altima Hybrid (35/33) and Nissan Versa (27/33) are also good choices. The Altima Hybrid, in fact, is luxurious and roomy inside, and would make a great choice for carpools. But don't expect much space when you open the trunk. The battery takes up much of the cargo space.
• Low-price compacts and subcompacts. The non-hybrid Honda Civic (25/36) is runner-up to the Toyota Yaris (29/36) in the subcompact class, although it is considerably more expensive at about $15,000 compared to $11,300 for the Yaris. The Scion xD is another good choice (27/33) and priced about the same as the Honda. Among the compacts, the Honda Civic Hybrid (40/45) is followed by the Toyota Corolla (28/37) and Kia Rio (27/32).

An important note about the safetyy of smaller cars: The Insurance Institute for Highway Safety gives many of the smaller cars good crash test ratings. But a spokesman reminded me that their tests simulate collisions with vehicles of the same size. So bigger is safer, particularly if you mainly use your car for high-speed driving.

To check out fuel economy ratings yourself, see the Environmental Protection Agency's listings.