RAZOR’S EDGE: The styling of the A6 looks like it was carved with a sword, but the interior is plush and welcoming.
RAZOR’S EDGE: The styling of the A6 looks like it was carved with a sword, but the interior is plush and welcoming.
PHOTO: GEORGE KENNEDY

You have probably seen the ad. It features a woman in a new Audi, about to fill it with diesel fuel. Everyone around her is screaming, but no one can get her attention. Finally, the gas station clerk comes running out and screams, “Hey lady! That’s diesel!” To which she replies, “I know.”

The clerk is yelling at the woman, but he is really yelling at you, the viewer. The message is clear: “Diesel is here, and we want you to get behind it.”

Around the world, diesel-powered vehicles are as numerous as their gasoline powered counterparts, but in America, diesel gets a bad rap as dirty and less efficient. While perceptions may be lagging, the reality is that those days are behind us, and the 2014 Audi A6 TDI is the shining pinnacle of diesel’s implementation in a performance luxury sedan.

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Audi has been at the forefront of automotive design for some time, and the A6 continues that trend. Seriously sinister LED headlights flank the demonstrative square grille, making the front end of the A6 one of the most identifiable on the road today.

My one critique of the front clip is that it looks too similar to the A4 and A5 front ends. But the visual similarities end after the windshield, as the A6 features a strong character line that runs the length of the car, ending with a rear end that features LED taillights.

Audi continues to prove it is still the best in the world when it comes to designing interiors. BMW may have been the one to create the user interface controller with iDrive, but Audi changed the game with MMI, or Multi-Media Interface. It is a dial in the center console that allows you to control the audio and climate systems as well as the navigation. MMI developed during a crucial time, when automakers were trying to cram so many features into their cars that they created an overflow of buttons. Audi’s system simplifies all that, and also allows the driver to tune the chassis and driving feel all from that silver center dial.

Now that most other automakers have developed their own versions of the same system, Audi has improved its ergonomic prowess by making the features you use most accessible through real-tactile controls, rather than digital menus. The push-button start, stereo volume knob, and forward/reverse track buttons are all exactly where the driver would rest his or her right hand.

Also in the center console is a small touch-sensitive pad. Most of the time, it is used to select radio presets, but when entering letters into the navigation system you can actually “draw” letters, or write them with your index finder. It is as intuitive as it sounds, and makes operation of the Google Maps-backed navigation system very straightforward.

The key feature to the A6 TDI is its diesel powerplant. It displaces 3.0-liters, and is turbocharged and intercooled. It features dual overhead camshafts, 24 valves, and direct fuel injection. The six-cylinder mill puts out a modest 240 hp but a thrilling 420 lb. ft. of torque. Horsepower may only be in the neighborhood of the 2.0-liter four-cylinder base engine, but has more torque than the up-rated S6 performance sedan. Fuel economy for 2014 Audi A6 TDI is 24 city, 38 highway. Our Globe-observed combined mileage was 27.8 mpg.

Power is routed through an eight-speed automatic transmission to Quattro all-wheel drive. The transmission features Tiptronic manual gear selection, which can be accomplished by either sliding the gear selector to the +/– gate or using the steering wheel-mounted paddle shifters.

The acceleration of the A6 TDI is brisk and surprising. Were it not for that oversized badge on the side, I would have sworn this was the V8-powered S8. Still, you’d best let the A6 TDI shift for itself. With eight gears, the manual mode is not very rewarding for either you or the car. I’d like to see next generation tap-shifters skip gears. Currently, if you tap down once, or even twice, it does not put you in a low enough gear to work as a truly effective pickup gear.

The acceleration of the diesel engine is stunning. People tend to forget how crucial torque is in a vehicle’s performance. In many respects, its more important than horsepower, but horsepower has the word “power” in it, hence the misnomer.

The starting price of an A6 TDI is $57,500. A little math is required to compare it to the base A6. Though the standard A6 Premium trim is $43,100, the TDI is only available in the uprated Premium Plus and Prestige trims. You get more, but you are paying more.

Diesel is a harder sell when you consider its price per gallon compared to gasoline. In other parts of the world, the prices of the two are much closer, making the decision a little easier. In America, it is still a premium product, and so are the vehicles that it fuels. The engine itself is expensive, which is why the A6 TDI costs so much. But for drivers looking to conserve fuel and drive an actually exciting car, a diesel engine is the way to go—and few deliver the performance along with style and technology like the A6 TDI.

2014 Audi A6 TDI

THE BASICS

Price: $57,500. As tested: $74,095. Fuel economy, EPA estimated: 24/38. Fuel economy, Globe observed: 28.7 mpg. Drivetrain: 3.0L turbocharged V6, 8AT, all-wheel-drive. Body: five-passenger sedan.

THE SPECIFICS

Horsepower: 240. Overall length: 193.9 in. Wheelbase 114.7 in. Height: 57.8 in. Width: 82.1 in. Curb weight: 4,178 lbs.

THE GOOD

Cutting edge styling, superb acceleration, best tech in the industry.

THE BAD

Expensive entry price, financial gains of diesel require extreme patience.

THE BOTTOM LINE

If you have the means, this is the diesel to have.

ALSO CONSIDER

BMW 535d, Mercedes-Benz E250 BlueTEC, Volkswagen Passat TDI.