Mercedes-Benz showed off the BlueTEC ML320 SUV at the 2008 New York auto show. According to Mercedes-Benz, its AddBlue technology makes the ML320 the world's cleanest diesel. The ML320 BlueTEC uses a turbocharged diesel 3.2-liter V-6 engine, producing 210 horsepower and 398 foot-pounds of torque. That engine is mated to a seven speed automatic transmission, giving it wide range of gear ratios appropriate for city and freeway driving. The ML320 BlueTEC represents the first use of AddBlue technology in the U.S. AddBlue is a urea-based liquid that, when injected into the exhaust stream, converts 80 percent of the nitrogen oxide into ammonia. The ML320 has a 7 gallon tank for AddBlue that needs refilling every 10,000 miles. With AddBlue, the ML320 meets the emissions requirements of all 50 states. Mercedes-Benz will follow the ML320 BlueTEC with R-Class and GL-class BlueTEC models.