Audi diesel invasion

Brian Harper, Canwest News Service

Along with the latest-generation common-rail piezo direct-injection system, exhaust gas recirculation and efficient turbocharging, the key to the TDI's low engine emissions is its cleaning system in the exhaust gas system, which reduces nitrous oxides by up to 90 per cent. A urea solution called AdBlue is sprayed into the catalytic converter. In the hot exhaust, the solution breaks down into ammonia, which the nitrous oxide then splits into nitrogen and water.

Beyond the powertrain, the Q7 gets Audi's quattro permanent four-wheel drive. The demand-based torque distribution through the quattro drive means all 406 pound-feet generated by the TDI diesel will be distributed to the wheels with most grip, ensuring traction and lateral stability.

As an upscale family hauler, the Q7 ranks right up there. Its gently curving roof, muscular haunches and trademark Audi shield-like grille make it stand out in a crowded parking lot. It has a boatload of passive and active safety features, it is fully contented with the de rigueur modern conveniences and it is spacious and versatile. What it adds with the 3.0 TDI V6 is much-needed fuel economy and a sense that driving the Q7 (and other full-size, diesel-powered sport-utes and crossovers) doesn't necessarily make you an environmental scofflaw.

Our short time in the vehicle still led Fletcher and me to the same conclusion. With all its benefits, why would anyone not want to get the diesel engine?