2009 Audi

threetangledtrinkets.blogspot.com
Audi has been teasing us for a couple of years now with the possibility of a diesel version of its Q7 sport - utility vehicle, but so far the model has been missing its roll call. Alas, it finally will come to the U. S. by early calendar - year 2009, as a 2009 model, with an emissions system that ' s 50 - state legal.

In order to get the engine to meet the strictest U. S. standards, the Q7 TDI now includes a number of technologies that weren ' t all used together in diesels until very recently. They include cylinder pressure sensors, NOx sensors, a second catalyst and, most importantly, a urea - injection system, which sprays the liquid directly into hot exhaust gases just ahead of the second catalyst, reducing NOx emissions and producing nitrogen and water instead from the tailpipe, without the use of precious metals or a cumbersome nature and maintenance needs of a NOx trap.

The urea solution, called AdBlue, will be stored in a 6. 2 - gallon tank, and lasts at least 10, 000 miles - more than enough to get you to the next oil change - though, according to Audi engineers, that ' s a worst - case - scenario. And the AdBlue is injected into the exhaust at a rate that isn ' t directly proportional to mileage or fuel use, according to engineers, but depending on driving style, trip length, and other conditions such as outside air temperature.

We recently had the chance to drive the clean - running Q7 3. 0 TDI in Ontario and were, as with a number of other diesel vehicles we ' ve driven over the past several years, very impressed with its drivability, tremendous torque, and refinement.

The third - generation direct - injection system is the chief reason for the engine ' s smooth idle, refinement, and good throttle response, along with its complete lack of sooty exhaust no matter how hard you drive it. Injection pressure is now maintained at about 29, 000 psi, and high - precision piezo injectors help smooth out the combustion process. At low engine speeds, a pilot injection helps further smooth out the combustion process in addition to the five injections are made every engine cycle. Its glow plugs enable a cold start in the coldest outside temperatures after only two seconds.

Once warmed up, the new TDI has very little of the diesel clatter that diesels had ten or twenty years ago. We ' ve said this before, but it bears repeating.

It ' s a bit more refined, too, both compared with the V - 10 in the Touareg ( which tends to sound like a big - rig motor at times ), and with the only other diesel SUV I ' ve driven in recent months - a Jeep Grand Cherokee CRD.

While it isn ' t nearly as powerful as the 5. 0 - liter turbo - diesel V - 10, with its 310 horsepower and 553 pound - feet, that ' s been available on the Volkswagen Touareg in non - CARB states, the 3. 0 - liter turbo - diesel V - 6 makes 221 hp and 406 lb - ft and is a much more practical choice for its cleaner emissions and much better fuel economy.

Euro - spec 3. 0 TDI models top out at 134 miles per hour, but in the U. S. the Q7 diesel will be electronically limited to 110 mph.

The 3. 0 TDI feels faster than the gasoline V - 6 model just off the line, and at highway speeds it actually feels stronger than the gasoline V - 8 in its capability to effortlessly squeeze past slower traffic or pull off not - quite - full - throttle passes without a downshift. There ' s more of a chance to drive quickly and stealthily without upsetting who ' s in the passenger seat.

The Q7 comes with a six - speed Tiptronic automatic transmission, which no doubt helps fuel economy, but the engine is so flexible and responsive that it feels as if all the gears aren ' t even needed. Quattro all - wheel drive is of course standard, and in the Q7 the system normally sends 60 percent of available torque to the rear wheels for secure traction and stability.

The real - world fuel economy is astounding for a vehicle with a curb weight of more than 5000 pounds. Audi claims about 25 mpg on the highway, so we expected to see less. We zeroed the trip computer out in a ten - mile stretch of suburban stop - and - go driving, in 30 - degree winter weather, and averaged 12. 1 km per 100 liters - more than 19 mpg - then settled into an 80 - mile trip from Niagara - on - the - Lake, Ontario up to Toronto on congested expressways ranging between 20 and 80 mph. On this stretch of hardly smooth, even driving, our average mileage rose to 9. 4 km / 100 l - a very impressive 25 mpg, which suggests considerably higher figures if maintaining a steady speed. But even at that, it amounts to a very practical range of more than 600 miles with the Q7 ' s 26 - gallon tank.

That mileage with the diesel is about double what the V - 8 model gets in the city ( EPA 12 city, 17 highway ) and at least 25 percent better than that of the V - 6 ( 14 / 20 ) in similar driving. And it punts the Audi Q7 into the same fuel - budget range as a gasoline - powered mid - size sedan.

What especially deserves underlining, after our test drive of the upcoming Q7 TDI, is that diesel engines deliver exceptionally good fuel economy in the type of driving that most Americans do, without a sacrifice in performance or hauling ability, and now with the AdBlue system, emissions that are better than soot - free.