Diesel engines aren't what they used to be. And that's a good thing.
Though drivers of big pickup trucks and tractor-trailers sing the praises of diesel for strength, fuel mileage and durability, automobile drivers in the United States turn up their noses at the memory of smelly, smoky diesels of the past.
But technology has changed that. New electronic fuel-injection and turbocharging systems have helped make diesel engines cleaner running, quieter and more powerful, with soaring miles per gallon that rival gas-electric hybrids.
For years, the only passenger cars available with diesel engines were at Volkswagen dealers, with diesel versions of the compact Jetta and Golf boasting fuel mileage in the 40-plus range.
A diesel option for the mid-size Passat was brought back in April after a lengthy absence, giving a thrifty alternative to buyers of mid-priced family sedans. The only competition is the new hybrid version of the Honda Accord.
VW's not alone in the diesel category anymore. For 2005, Mercedes-Benz has a performance-oriented diesel version of the E-Class sedan, and Jeep has a new diesel for its Liberty sport utility vehicle.
Diesel engines are overwhelmingly popular in Europe, where gasoline prices are double those in this country, because of their high fuel mileage, low maintenance and the more-modest cost of clean low-sulfur diesel fuel. In the United States, diesel-fuel prices are not much lower than regular unleaded, which lessens the appeal.
Diesels are not welcome in every state, either. Clean-air standards ban their sale in California, Massachusetts, New York, New Jersey, Maine and Vermont. But starting in 2006, EPA-mandated clean diesel fuel, with 97 percent less sulfur content than today, could allow automakers to clean up their diesels to meet the more stringent standards.
Watch for more diesel cars on the horizon, and possibly in your future.
What it is A new diesel version of the popular sedan, Passat TDI joins VW's other diesel offerings, including a powerful V-10 diesel for the Touareg sport utility vehicle.
The TDI designation stands for turbocharged direct injection, and the Passat tested here was the upgraded GLS model.
Performance Though 134 horsepower may not sound like much for a 3,450-pound sedan, diesel engines are all about torque, and the two-liter four in the Passat churns out 247 pound-feet of muscle at a low 1,900 rpm. Torque is a measurement of pulling power, which gives an engine its strength and acceleration.
VW's high-tech unit-injection system provides precise fuel metering, which helps the engine run more efficiently with less noise and better fuel mileage. The turbocharger adds to the engine power.
The four-cylinder diesel engine in the Passat can feel a bit strange, the RPMs droning in a low range even as the car picks up speed, in contrast with the familiar revving accompaniment of a gasoline engine. Acceleration is hardly stellar, this being just a two-liter engine, but it's comparable to the performance of a small conventional V-6.
Where the diesel really shines is in highway driving, where it rolls along with hardly a whisper of engine roar, the RPMs remaining around 2,000 even at 75-plus miles per hour. The engine shrugs off steep grades.
And here's a first: my fuel mileage in the Passat actually was better than the 27 city, 38 highway calculated by the EPA, according to the VW's on-board trip computer. In urban driving, I got 30 mpg, and in a highway trip from Phoenix to Dewey and back, the computer registered 40 mpg. I wasn't sparing the power, either.
In urban driving, the test car shuddered unpleasantly at low speeds, the engine feeling slightly choked up when the throttle was applied lightly or when lifting off. This could have been a fault in the test car rather than an overall complaint.
Drivability The suspension is firm in the European style. The steering is light but direct, and the four-wheel disc brakes have good stopping power.
Styling Though recently upgraded, the Passat seems staid and conservative. VW should look toward its Audi luxury division for inspiration. Standard 15-inch alloy wheels add some sporty flair.
Interior Simple and sturdy, with a well-organized feel throughout, the Passat remains a class act in family-car interiors. Accommodations are roomy for people in both the front and rear seats, and the trunk is huge.
Pricing The GLS comes loaded with standard equipment, including the full boat of power windows, locks and mirrors; power moonroof; trip computer; telescoping steering column; keyless entry; CD audio system; and such safety features as side-impact and curtain airbags, and antilock brakes.
The diesel engine adds just $205 to the base price of the Passat GLS, which comes to $23,585. The test car included a five-speed automatic transmission, $1,075; cold-weather package, $325; electronic stabilization program, which helps avoid skids, $280; and shipping, $525.
At $25,840 total, the Passat GLS TDI feels like a solid bargain for a solid, spacious and good-running diesel car.
Bottom line With excellent drivability and good power from its quiet engine, the Passat TDI makes it easy to forget the sins of yesterday's diesels.