Like every German manufacturer, Volkswagen is continuing the push for clean diesel in the United States. Spearheaded by the Jetta TDI Clean Diesel release late this summer, the influx of diesel vehicles from Wolfsburg now continues with the Touareg V6 TDI. Unlike its smaller-engine brother, however, the Touareg will make do with the use of special catalytic converters and a fluid you know in yellow called AdBlue, to cleanse the tailpipe.

Nevertheless, the big Touareg uses VW’s latest common rail technology (that’s third-generation, for those who might be counting) to produce fuel pressures of more than 29,000 psi to atomize fuel. As you might imagine, the system produces a very fine mist. There’s also a noise-damping system to help keep diesel clatter down to a minimum for sensitive American ears. Sensors within the combustion chamber (mounted on the glow plugs themselves), can consistently measure cylinder pressure to determine the ideal injection and combustion for each cylinder, while the turbochargers breathe through dual intercoolers. In an effort to help the SUV warm up as quickly as possible (thus reducing emissions), these intercoolers are bypassed until ideal operating temperature is reached.

But the reason you’ll see any diesel SUVs in America remains the same: There’s urea in the exhaust (yes, it’s the yellow fluid you’re thinking of). If you haven’t heard of AdBlue yet, you can bet you will soon. Injected into a special SCR (selective catalytic reduction) catalytic converter, nitrogen oxide emissions are reduced by about 90 percent, converted into water and nitrogen without any side products. The AdBlue tank is located just under the spare tire, and holds four gallons of the stuff, which is injected constantly when driving. You’ll need to have the tank professionally refilled about every 10,850 miles during normal driving, according to Volkswagen, but they promise it will be cheap. In addition, there’s a traditional oxidation catalytic converter as well as a diesel particulate filter, which is how the company gets away with the “white handkerchief” exhaust-pipe test (it stays white).

The turbocharged 3.0-liter engine develops 222 horsepower and a predictably impressive 405 lb-ft of torque. Notably, that peak torque is achieved at just 1750 rpm – a nice perk of diesel engines. But the technology hasn’t gone into making the Touareg TDI fast (it’s actually no slouch, getting to 60 miles per hour in 8.5 seconds according to Volkswagen). The primary use of all the new tech is obviously to make the Touareg clean. And clean it is, qualifying to meet even strict BIN 5 regulations, making it legal in all 50 states. Of course, because the idea of diesel as an efficient means of propulsion is a new concept on these shores, Volkswagen is also happy to announce the 17/25 mpg (city/hwy) EPA rating, which makes this the cleanest and most efficient Touareg ever built.

Other than the unexpected swell of torque and mass of technology, this is a Touareg like any other you may have experienced. It will be in showrooms in early 2009.