Everybody in the auto industry -- including luxury carmakers -- is worried about gas prices and the impact they will have on auto sales.

As a result, you can expect to see plenty of diesel products coming onto the market in years to come.

Of course, for some companies -- namely luxury automaker Mercedes-Benz -- diesel is nothing new. They've been selling diesels around the world even when diesel engines weren't popular.

And yes, like other diesel automakers of the past, some had the same issues that people used to associate with diesel: noise, stinkiness and sluggish performance.

But that was then. This is now.

Meet Mercedes' 2008 ML320 CDI V-6. This one is everything you thought a diesel-powered car wasn't: Clean, with no foul odors, no shaking and no vibrating when you start it. And it certainly is no slow poke.

The centerpiece of the car is what Mercedes is billing as a "new-generation" V-6 diesel engine with four valves per cylinder, dual overhead camshafts, and centrally located "piezo ceramic fuel injectors."

"Piezos" are crystals that change shape anytime an electric current is applied, and they help make for faster, more durable injectors. The diesel fuel is sprayed directly into the center of the combustion chamber, and it's laid out to provide even dispersion of the diesel fuel.

The fact that the engine in the ML320 CDI V-6 has four valves per cylinder is important. Mercedes says that if this were a two-valve-per-cylinder diesel engine, the injectors could not be installed in a central location, and that would create uneven combustion, less power and higher exhaust emissions.

But enough technical talk.

Does it work? You bet.

While the engine feels a bit slow and sluggish at first, it quickly acclimates itself to the action and performs beautifully in traffic and on the open road.

Our test model had a base price of $44,650, $60,090 with options.

The ML320 is a large, heavy sport-utility vehicle. Yet with this 215-horsepower, 3.0-liter V-6 diesel engine, it's rated at 18/24 miles per gallon with a $2,000 estimated annual fuel cost.

It's quiet, supremely comfortable, and provides everybody on board with a sense of security and stability, making it a very good car for long-distance traveling.

The interior is typically Mercedes: lush, comfortable, and done only with the best materials. It also features a more "old-school" Mercedes interior, while the company has switched to a more contemporary look inside and out for most of its products.

Handling was predictable and safe, with no "trucky" attributes to spoil the fun.

And quality control is up, too. When the ML-Class was first introduced years ago, it quickly got a reputation for electrical glitches and problems of various sorts, but that's certainly gotten much better.

My problems were familiar ones: The turn signal stalk is located too close to the cruise control lever, something that should be changed.

There also was the navigation and "COMAND" system, which has a bewildering number of buttons and controls.

And consumers are starting to complain about the graphics and dated look of the navigation system, too. The COMAND display could have better resolution and color.

And the navigation user interface stinks. Any $250 stand-alone navigation device would be much better with 3-D renderings and intuitive design, groused one owner in an online chat room.

But the same owner raved about the rest of the car. "I had been nervous about MB's less than stellar reputation in quality," the owner said. "[But] my car has so far exceeded all my expectations in terms of performance and quality.

"It has tremendous diesel power that propels the car into any traffic when needed. But mostly I like driving very gently, and the car rewards me with 30 miles per gallon on highways."

Other consumers liked the "very smooth highway riding," "good fuel economy," "good riding comfort, handling and off-road capability."